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RSS2012 Vol. 24, No. 07
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2012,
24: 1513-1514.
doi: 10.3788/HPLPB20122407.1513
Abstract:
Gyro-TWT (traveling wave tube) with helical waveguide has wider instantaneous frequency bandwidth than that with smooth waveguide. This paper introduces the nonlinear theory of its beam-wave interaction. The calculation shows that, the electron efficiency reaches 29%, and the saturated gain is 37 dB, when the working magnetic field is 0.21 T, the voltage is 185 kV and the current is 19 A. The calculated results accord with that reported in literature.
Gyro-TWT (traveling wave tube) with helical waveguide has wider instantaneous frequency bandwidth than that with smooth waveguide. This paper introduces the nonlinear theory of its beam-wave interaction. The calculation shows that, the electron efficiency reaches 29%, and the saturated gain is 37 dB, when the working magnetic field is 0.21 T, the voltage is 185 kV and the current is 19 A. The calculated results accord with that reported in literature.
2012,
24: 1515-1516.
Abstract:
A passively Q switched fiber laser near 2 m band was obtained based on semiconductor saturable absorber mirror and fiber grating. The central wavelength of the laser was 1958.2 nm. The pulse repetition rate of output signal increases with the rise of incident pump power, but the pulse width decreases. The pulse repetition rate was in the range of 20 kHz to 80 kHz and the pulse width was changed from 490 ns to 1 s. When the incident pump power was 1.3 W, the maximum output power of the Qswitched fiber laser was 91 mW, the pulse repetition rate was 80 kHz, the pulse width was 490 ns and the single pulse energy was 1.14 J.
A passively Q switched fiber laser near 2 m band was obtained based on semiconductor saturable absorber mirror and fiber grating. The central wavelength of the laser was 1958.2 nm. The pulse repetition rate of output signal increases with the rise of incident pump power, but the pulse width decreases. The pulse repetition rate was in the range of 20 kHz to 80 kHz and the pulse width was changed from 490 ns to 1 s. When the incident pump power was 1.3 W, the maximum output power of the Qswitched fiber laser was 91 mW, the pulse repetition rate was 80 kHz, the pulse width was 490 ns and the single pulse energy was 1.14 J.
2012,
24: 1517-1522.
Abstract:
In the procedures of designing polystyrene-polyvinyl alcohol-CH (carbon and hydrogen elements) (PS-PVA-CH) triple-layer microspheres, there are many methods such as drop-tower technique, emulsion micro-encapsulation, dip (spin) coating, interfacial polycondensation, and spraying technique to prepare the PVA coating. Drop-tower technique, emulsion micro-encapsulation and dip (spin) coating are most-commonly used. The advantages, disadvantages and the research progress of the three methods are summarized in this paper. Emulsion micro-encapsulation is suitable for preparing double-layer microspheres of sizes smaller then 500 m, with high survival ratio and good quality. However,the preparation process is easily influenced by artificial factors. Small-sized double-layer microspheres can also be prepared by the drop-tower technique, and the preparation period is short. But there are still some problems such as the difficulty in designing thedroplet generator, uneven PVA coating and the difficulty in preparing large-sized microspheres. Dip (spin) coating technique can be used to prepare PS-PVA microspheres with sizes larger than 1000 m, but the spread of PVA coating is affected by many factors in this method, and the prepared PVA coating is too thin and not uniform.
In the procedures of designing polystyrene-polyvinyl alcohol-CH (carbon and hydrogen elements) (PS-PVA-CH) triple-layer microspheres, there are many methods such as drop-tower technique, emulsion micro-encapsulation, dip (spin) coating, interfacial polycondensation, and spraying technique to prepare the PVA coating. Drop-tower technique, emulsion micro-encapsulation and dip (spin) coating are most-commonly used. The advantages, disadvantages and the research progress of the three methods are summarized in this paper. Emulsion micro-encapsulation is suitable for preparing double-layer microspheres of sizes smaller then 500 m, with high survival ratio and good quality. However,the preparation process is easily influenced by artificial factors. Small-sized double-layer microspheres can also be prepared by the drop-tower technique, and the preparation period is short. But there are still some problems such as the difficulty in designing thedroplet generator, uneven PVA coating and the difficulty in preparing large-sized microspheres. Dip (spin) coating technique can be used to prepare PS-PVA microspheres with sizes larger than 1000 m, but the spread of PVA coating is affected by many factors in this method, and the prepared PVA coating is too thin and not uniform.
2012,
24: 1523-1527.
Abstract:
Organic thin-film transistors (OTFTs) have attracted extensive attention due to their unique properties, such as the diversity of organic materials, easy fabrication approaches and compatibility with flexible substrates. This paper introduces the research progress of OTFTs, and further analyzes the basic structure, working principle and electrical properties of OTFTs. The development history of sensors based on OTFTs are summarized. The advantages of the OTFT-based sensors are introduced with emphasis on their sensitivity and selectivity. Finally, the working mechanism of the OTFT-based sensors is analyzed.
Organic thin-film transistors (OTFTs) have attracted extensive attention due to their unique properties, such as the diversity of organic materials, easy fabrication approaches and compatibility with flexible substrates. This paper introduces the research progress of OTFTs, and further analyzes the basic structure, working principle and electrical properties of OTFTs. The development history of sensors based on OTFTs are summarized. The advantages of the OTFT-based sensors are introduced with emphasis on their sensitivity and selectivity. Finally, the working mechanism of the OTFT-based sensors is analyzed.
2012,
24: 1528-1532.
Abstract:
By using the generalized Rayleigh-Sommerfeld diffraction integral, the analytical expression for the cross-spectral density matrix of nonparaxial spatially and spectrally partially coherent electromagnetic Cosh-Gaussian(ChG) pulsed beams propagating in free space was derived and used to formulate the spectral density (intensity) and spectral degree of polarization of electromagnetic pulsed beams. It is found that the parameters f and f play an important role in determining the nonparaxiality of spatially and spectrally partially coherent electromagnetic ChG pulsed beams in the far field, and the decentered parameter, pulse duration, and temporal coherence length affect the nonparaxial behavior. Far-field propagation of nonparaxial spatially and spectrally partially coherent electromagnetic Gaussian Schell-model pulsed beams can be treated as a special case of our results.
By using the generalized Rayleigh-Sommerfeld diffraction integral, the analytical expression for the cross-spectral density matrix of nonparaxial spatially and spectrally partially coherent electromagnetic Cosh-Gaussian(ChG) pulsed beams propagating in free space was derived and used to formulate the spectral density (intensity) and spectral degree of polarization of electromagnetic pulsed beams. It is found that the parameters f and f play an important role in determining the nonparaxiality of spatially and spectrally partially coherent electromagnetic ChG pulsed beams in the far field, and the decentered parameter, pulse duration, and temporal coherence length affect the nonparaxial behavior. Far-field propagation of nonparaxial spatially and spectrally partially coherent electromagnetic Gaussian Schell-model pulsed beams can be treated as a special case of our results.
2012,
24: 1533-1538.
Abstract:
A method based on image processing is proposed to measure the zero time of launching, after the analysis on the disadvantages of the current methods. The method is a non-contact measurement based on high frame rate camera and image processing technique. It considers the change in horizontal projection of the feature area to be the horizontal displacement of the target. When the displacement is larger than the threshold, the zero time is triggered. An experimental simulation considering different factors has been carried out according to actual situations. The results reveal that, the algorithm can provide real-time and reliable zero time signals by detecting 1 cm movement at a distance of 300 m in 10 ms.
A method based on image processing is proposed to measure the zero time of launching, after the analysis on the disadvantages of the current methods. The method is a non-contact measurement based on high frame rate camera and image processing technique. It considers the change in horizontal projection of the feature area to be the horizontal displacement of the target. When the displacement is larger than the threshold, the zero time is triggered. An experimental simulation considering different factors has been carried out according to actual situations. The results reveal that, the algorithm can provide real-time and reliable zero time signals by detecting 1 cm movement at a distance of 300 m in 10 ms.
2012,
24: 1539-1543.
Abstract:
To improve the performances of chemical oxygen iodine laser (COIL), experiments were done for the removal of water vapor content in singlet oxygen gas flows by using -117 ℃ ethanol (C2H5OH), -110 ℃ freon (CCI3F) and -45 ℃,50% hydrogen peroxide (H2O2) cold jets respectively. Experimental results show that dehydration effects of the three cold jets are not so remarkable: C2H5OH has scarcely any dehydration effect, and CCI3F and H2O2 can only reduce water vapor contents to about 1/5 and 1/4 of the initial values respectively. C2H5OH and CCI3F are so readily volatilized that they would produce severe interference in the gas flows and are not applicable to the removal of water vapor. Only the nonvolatile H2O2 is the suitable candidate.
To improve the performances of chemical oxygen iodine laser (COIL), experiments were done for the removal of water vapor content in singlet oxygen gas flows by using -117 ℃ ethanol (C2H5OH), -110 ℃ freon (CCI3F) and -45 ℃,50% hydrogen peroxide (H2O2) cold jets respectively. Experimental results show that dehydration effects of the three cold jets are not so remarkable: C2H5OH has scarcely any dehydration effect, and CCI3F and H2O2 can only reduce water vapor contents to about 1/5 and 1/4 of the initial values respectively. C2H5OH and CCI3F are so readily volatilized that they would produce severe interference in the gas flows and are not applicable to the removal of water vapor. Only the nonvolatile H2O2 is the suitable candidate.
2012,
24: 1544-1548.
Abstract:
The influence of quartz tube on the electric field intensity in the parallel WR-430 waveguide resonant cavity is discussed. The electric field intensity has an abrupt change like a positive impulse near every slot and the impulse peak increases along the surface of one waveguide while decreases along the surface of the other when there is no quartz tube. In the presence of quartz tube, the electric field intensity gets weaker and fluctuates more irregularly along the wall of quartz tube. Noteworthily, it waves along the axis of the plasma generation zone in these two cases. While the wall thickness of quartz tube is 5 mm and the distance of quartz tube from waveguides is 2 mm, the average electric field intensity reaches maximum and the high electric field area is comparatively large. The maximum electric field intensity decreases with the increase of the wall thickness and distance for their values respectively greater than 5 and 2 mm. Low-pressure (1 500 Pa) and atmospheric air microwave plasmas are produced and their appearances are much similar to corresponding side-distributions of electric field intensity.
The influence of quartz tube on the electric field intensity in the parallel WR-430 waveguide resonant cavity is discussed. The electric field intensity has an abrupt change like a positive impulse near every slot and the impulse peak increases along the surface of one waveguide while decreases along the surface of the other when there is no quartz tube. In the presence of quartz tube, the electric field intensity gets weaker and fluctuates more irregularly along the wall of quartz tube. Noteworthily, it waves along the axis of the plasma generation zone in these two cases. While the wall thickness of quartz tube is 5 mm and the distance of quartz tube from waveguides is 2 mm, the average electric field intensity reaches maximum and the high electric field area is comparatively large. The maximum electric field intensity decreases with the increase of the wall thickness and distance for their values respectively greater than 5 and 2 mm. Low-pressure (1 500 Pa) and atmospheric air microwave plasmas are produced and their appearances are much similar to corresponding side-distributions of electric field intensity.
2012,
24: 1549-1554.
Abstract:
For the requirements of triggering numerous gas switches in linear transformer drivers (LTD) synchronously, a multi-output synchronous triggering technology named LTD-trigger is proposed based on the reversed-LTD configuration and inductive transformer principle. It operates like numbers of pulse transformer in series. With one primary fast high-voltage pulsed power supply, multichannel fast triggering pulses can be obtained through the inductive coupling of a pulse transformer at secondary, corresponding to gas switches in LTDs. It effectively reduces the delay and jitter time due to the intrinsic advantages of the coaxial configuration compared with the conventional triggering method. With careful design, LTD-trigger can meet the requirement for switches in LTDs. This paper analyzed the working principle of LTD-trigger by establishing a circuit model and simulation. With analysis of some fault modes and preliminary experiments, the feasibity of LTD-trigger is confirmed.
For the requirements of triggering numerous gas switches in linear transformer drivers (LTD) synchronously, a multi-output synchronous triggering technology named LTD-trigger is proposed based on the reversed-LTD configuration and inductive transformer principle. It operates like numbers of pulse transformer in series. With one primary fast high-voltage pulsed power supply, multichannel fast triggering pulses can be obtained through the inductive coupling of a pulse transformer at secondary, corresponding to gas switches in LTDs. It effectively reduces the delay and jitter time due to the intrinsic advantages of the coaxial configuration compared with the conventional triggering method. With careful design, LTD-trigger can meet the requirement for switches in LTDs. This paper analyzed the working principle of LTD-trigger by establishing a circuit model and simulation. With analysis of some fault modes and preliminary experiments, the feasibity of LTD-trigger is confirmed.
2012,
24: 1555-1560.
Abstract:
The paper presents the numerical and experimental study of shearing interferometric tomography for Richtmyer-Meshkov instability diagnosis. On the basis of simultaneous algebraic reconstruction technique (SART), a method is presented to compute the projection coefficient matrix using specific projection directions and different sampling interval for each direction. The symmetrical projection and projection ray regularity simplify the computing process of the conventional SART. The reconstruction of the density field of a gas cylinder was performed. The numerical results show that four-directional computer tomography（CT） can reconstruct the density field in the early stage of evolution and eight-directional CT has the maximal error less than 17% in the middle stage of evolution. Three shearing interferometers were used to measure the gas cylinder density in shock tube from three different directions. The phase distribution deduced from the interferograms basically coincides with the theoretical prediction. The results of numerical computation and experiment indicate that shearing interferometric tomography may be a useful tool for the study of Richtmyer-Meshkov instability.
The paper presents the numerical and experimental study of shearing interferometric tomography for Richtmyer-Meshkov instability diagnosis. On the basis of simultaneous algebraic reconstruction technique (SART), a method is presented to compute the projection coefficient matrix using specific projection directions and different sampling interval for each direction. The symmetrical projection and projection ray regularity simplify the computing process of the conventional SART. The reconstruction of the density field of a gas cylinder was performed. The numerical results show that four-directional computer tomography（CT） can reconstruct the density field in the early stage of evolution and eight-directional CT has the maximal error less than 17% in the middle stage of evolution. Three shearing interferometers were used to measure the gas cylinder density in shock tube from three different directions. The phase distribution deduced from the interferograms basically coincides with the theoretical prediction. The results of numerical computation and experiment indicate that shearing interferometric tomography may be a useful tool for the study of Richtmyer-Meshkov instability.
2012,
24: 1561-1565.
Abstract:
During the curing process of double emulsions for fabricating poly(a-methylstyrene) (PAMS) capsules by microencapsulation technology, the match of density between the water in oil compound droplet and the outer water phase is vital to the sphericity of PAMS capsules. To investigate the effects of density mismatch on the sphericity of the resulting PAMS capsules, the densities of compound droplets with different inner diameters and polymer oil layer thicknesses were calculated theoretically and measured experimentally during the curing process. Also, the polymer concentrations of the oil phase in the compound droplets during the curing process were further studied. The results show that, the density mismatch between the compound droplets and the outer water phase can be quantitatively controlled by adjusting the compositions of the outer water phase. The curing stage with the polymer concentration of the oil phase increasing from 20% to 60% is the key phase of the curing process. When the density mismatch between the compound droplets and the outer water phase lowering from 0.004 95 g/cm3 to 0.000 02 g/cm3, the number percentage of PAMS capsules with out of round(OOR） value less than 10 m in batches can be increased from 14.3% to 93.3%. Thus for the compound droplets with different inner diameters and polymer oil layer thicknesses, the sphericity of the resulting PAMS capsules can be significantly improved, through reducing the density mismatch between the compound droplets and the outer water phase in the key phase of the curing process.
During the curing process of double emulsions for fabricating poly(a-methylstyrene) (PAMS) capsules by microencapsulation technology, the match of density between the water in oil compound droplet and the outer water phase is vital to the sphericity of PAMS capsules. To investigate the effects of density mismatch on the sphericity of the resulting PAMS capsules, the densities of compound droplets with different inner diameters and polymer oil layer thicknesses were calculated theoretically and measured experimentally during the curing process. Also, the polymer concentrations of the oil phase in the compound droplets during the curing process were further studied. The results show that, the density mismatch between the compound droplets and the outer water phase can be quantitatively controlled by adjusting the compositions of the outer water phase. The curing stage with the polymer concentration of the oil phase increasing from 20% to 60% is the key phase of the curing process. When the density mismatch between the compound droplets and the outer water phase lowering from 0.004 95 g/cm3 to 0.000 02 g/cm3, the number percentage of PAMS capsules with out of round(OOR） value less than 10 m in batches can be increased from 14.3% to 93.3%. Thus for the compound droplets with different inner diameters and polymer oil layer thicknesses, the sphericity of the resulting PAMS capsules can be significantly improved, through reducing the density mismatch between the compound droplets and the outer water phase in the key phase of the curing process.
2012,
24: 1566-1568.
Abstract:
A permanent magnet assembly is presented according to the primary requirement for the magnetic field in the particle spectrometer. The permanent magnet assembly adopts the C-type magnetic circuit along with assistant magnets. Magnet circuits are validated and optimized by simulation technology. The results of both simulation and experiments show that the uniform working region is enlarged， and the magnetic field homogeneity is improved with the optimized magnetic circuit. The Magnetic field strength of the optimized permanent magnet assembly is up to 0.75 T in the uniform working region of 200 mm120 mm， and the magnetic field inhomogeneity is 0.67%.In addition， the magnetic properties of the permanent magnet assembly at different temperatures are simulated, the change rate of the magnetic field strength in the uniform region is about 4% from -55~70 ℃.
A permanent magnet assembly is presented according to the primary requirement for the magnetic field in the particle spectrometer. The permanent magnet assembly adopts the C-type magnetic circuit along with assistant magnets. Magnet circuits are validated and optimized by simulation technology. The results of both simulation and experiments show that the uniform working region is enlarged， and the magnetic field homogeneity is improved with the optimized magnetic circuit. The Magnetic field strength of the optimized permanent magnet assembly is up to 0.75 T in the uniform working region of 200 mm120 mm， and the magnetic field inhomogeneity is 0.67%.In addition， the magnetic properties of the permanent magnet assembly at different temperatures are simulated, the change rate of the magnetic field strength in the uniform region is about 4% from -55~70 ℃.
2012,
24: 1569-1574.
Abstract:
According to current magnetic and processing conditions, a gradually-changing reversal magnetic system and a practical 8 mm third-harmonic peniotron electron gun are designed. This large-orbit electron gun is designed under the operating voltage of 43.5 kV, and operating current of 1.45 A, and its cathode can be located in the axial magnetic field where its magnitude decreases gradually. It does not demand the consistency between the field lines and the contour of the beam trajectories, which reduces the design requirements and difficulty greatly. After optimization, an axis-encircling electron beam with an axial velocity spread of 4.78%, a guiding center deviation ratio of 7.18% and a velocity ratio of 2.2 is obtained, which satisfies the requirements of the third-harmonic peniotron. The large-signal simulation shows that, driven by the electron gun, the peniotron can achieve an output power of 31.9 kW with the efficiency up to 49.4%. This is an attractive result in laboratory platform.
According to current magnetic and processing conditions, a gradually-changing reversal magnetic system and a practical 8 mm third-harmonic peniotron electron gun are designed. This large-orbit electron gun is designed under the operating voltage of 43.5 kV, and operating current of 1.45 A, and its cathode can be located in the axial magnetic field where its magnitude decreases gradually. It does not demand the consistency between the field lines and the contour of the beam trajectories, which reduces the design requirements and difficulty greatly. After optimization, an axis-encircling electron beam with an axial velocity spread of 4.78%, a guiding center deviation ratio of 7.18% and a velocity ratio of 2.2 is obtained, which satisfies the requirements of the third-harmonic peniotron. The large-signal simulation shows that, driven by the electron gun, the peniotron can achieve an output power of 31.9 kW with the efficiency up to 49.4%. This is an attractive result in laboratory platform.
2012,
24: 1575-1578.
Abstract:
Researches on scintillators sensitivity calibration method has been carried out recently in Shanghai synchrotron radiation facility. By some experimental researches in light source and detectors linearity, it built a new method for calibrating scintillators sensitivity. Finally, calibration results were acquired by theory simulation of experimental data which were in accordance with radioactive source method's results, and the new method improved the data accuracy.
Researches on scintillators sensitivity calibration method has been carried out recently in Shanghai synchrotron radiation facility. By some experimental researches in light source and detectors linearity, it built a new method for calibrating scintillators sensitivity. Finally, calibration results were acquired by theory simulation of experimental data which were in accordance with radioactive source method's results, and the new method improved the data accuracy.
2012,
24: 1579-1583.
Abstract:
In order to study the coupling response law of continuous wave electromagnetic irradiation to coaxial cable, the typical RF coaxial cable is selected as the object under test. The equipment or subsystem connected by coaxial cable is equivalent to a lumped load. Continuous wave irradiation effect experiments under different conditions are carried out to analyze the terminal load response law of coaxial cable. The results indicate that the coaxial cable has a frequency selecting characteristic under electromagnetic irradiation, and the terminal load response voltage peak appears at a series of discrete frequency points where the test cables relative lengths equal to semi-integers. When the coaxial cable is irradiated by continuous wave, the induced sheath current converts to the differential-mode induced voltage between inner conductor and shielding layer through transfer impedance, and the internal resistance of induced voltage source is the characteristic impedance of the coaxial cable. The change in terminal load value has no influence on the response curve. The voltages on the terminal load and the internal resistance of equivalent induced voltage source obey the principle of voltage division. Moreover, when the sheath current on the coaxial cable is in resonance, the distributed induced voltage between adjacent current nodes is in the same polarity, which can be equivalent to a single induced voltage source. The induced voltage source which is adjacent to the terminal load plays the leading role in the irradiation response process.
In order to study the coupling response law of continuous wave electromagnetic irradiation to coaxial cable, the typical RF coaxial cable is selected as the object under test. The equipment or subsystem connected by coaxial cable is equivalent to a lumped load. Continuous wave irradiation effect experiments under different conditions are carried out to analyze the terminal load response law of coaxial cable. The results indicate that the coaxial cable has a frequency selecting characteristic under electromagnetic irradiation, and the terminal load response voltage peak appears at a series of discrete frequency points where the test cables relative lengths equal to semi-integers. When the coaxial cable is irradiated by continuous wave, the induced sheath current converts to the differential-mode induced voltage between inner conductor and shielding layer through transfer impedance, and the internal resistance of induced voltage source is the characteristic impedance of the coaxial cable. The change in terminal load value has no influence on the response curve. The voltages on the terminal load and the internal resistance of equivalent induced voltage source obey the principle of voltage division. Moreover, when the sheath current on the coaxial cable is in resonance, the distributed induced voltage between adjacent current nodes is in the same polarity, which can be equivalent to a single induced voltage source. The induced voltage source which is adjacent to the terminal load plays the leading role in the irradiation response process.
2012,
24: 1584-1588.
Abstract:
An emittance measurement instrument based on embedded system was introduced. The instrument was based on slit-wire method. It had seven different measurement ranges, and its data sampling rate was up to 200 kHz. The system construction and working principle were discussed. The design and production of the data acquisition system were also discussed. The analog signal circuit was established by using high-speed, low-noise integrated chips, along with appropriate resistors and capacitors. The filters in every stage, the low-noise power supply technology and the shielding technology insure the realization of a low-noise data acquisition circuit. The results of tests show that the acquisition accuracy is 1.47% at the measurement range of 10 nA, and up to 0.32% at the range of 1 A. The harmonic distortion is 6.5 dB when a sine wave is sampled with the frequency of 20 kHz. The fastest movement speed is 3.125 mm/s at the movement accuracy of 1.25 m.
An emittance measurement instrument based on embedded system was introduced. The instrument was based on slit-wire method. It had seven different measurement ranges, and its data sampling rate was up to 200 kHz. The system construction and working principle were discussed. The design and production of the data acquisition system were also discussed. The analog signal circuit was established by using high-speed, low-noise integrated chips, along with appropriate resistors and capacitors. The filters in every stage, the low-noise power supply technology and the shielding technology insure the realization of a low-noise data acquisition circuit. The results of tests show that the acquisition accuracy is 1.47% at the measurement range of 10 nA, and up to 0.32% at the range of 1 A. The harmonic distortion is 6.5 dB when a sine wave is sampled with the frequency of 20 kHz. The fastest movement speed is 3.125 mm/s at the movement accuracy of 1.25 m.
2012,
24: 1589-1594.
Abstract:
The ionization beam profile monitor(IPM) was designed for the beamline of GIC4117 tandem accelerator. The key aspects of the design, such as the calculation of collecting signal intensity, design and optimization of the electric and magnetic field system using a 3-D finite element program are described. The incorporation of an auxiliary magnetic field makes it possible for the IPM to correct the beam orbit automatically. The transverse motion of the ionized electrons is critical to the accuracy of the beam profile measurement. Both theoretical analysis and tracking results of the transverse motion of ionized electrons were done based on the optimized field. The orbit tracking results show that the transverse motion deviation is less than 0.3 mm, which agrees well with the theoretical analysis results.
The ionization beam profile monitor(IPM) was designed for the beamline of GIC4117 tandem accelerator. The key aspects of the design, such as the calculation of collecting signal intensity, design and optimization of the electric and magnetic field system using a 3-D finite element program are described. The incorporation of an auxiliary magnetic field makes it possible for the IPM to correct the beam orbit automatically. The transverse motion of the ionized electrons is critical to the accuracy of the beam profile measurement. Both theoretical analysis and tracking results of the transverse motion of ionized electrons were done based on the optimized field. The orbit tracking results show that the transverse motion deviation is less than 0.3 mm, which agrees well with the theoretical analysis results.
2012,
24: 1595-1598.
Abstract:
Solid insulating materials may increase the leakage flux of insulated core flat winding transformer(ICFWT). This results in a low generated voltage in the secondary coils, especially on the upper stages. Parallelly connecting an appropriate compensation capacitor to the secondary coil on every stage will cancel the flux loss. Design equations to calculate the value of flux compensation capacitors and relevant simulations by CST and Protel are presented. Simulation results of an actual ICFWT show that the output voltage increases by 17.6% with compensation. At the same time, every stage generates almost the same voltage. Simulation results are consistent with the results of subsequent experimental tests, which again confirms the effectiveness of flux compensation capacitors.
Solid insulating materials may increase the leakage flux of insulated core flat winding transformer(ICFWT). This results in a low generated voltage in the secondary coils, especially on the upper stages. Parallelly connecting an appropriate compensation capacitor to the secondary coil on every stage will cancel the flux loss. Design equations to calculate the value of flux compensation capacitors and relevant simulations by CST and Protel are presented. Simulation results of an actual ICFWT show that the output voltage increases by 17.6% with compensation. At the same time, every stage generates almost the same voltage. Simulation results are consistent with the results of subsequent experimental tests, which again confirms the effectiveness of flux compensation capacitors.
2012,
24: 1599-1602.
Abstract:
In order to reduce the size and gain of the high power microwave measurement receiving antenna, a small-sized expanded coaxial line antenna operating at L-band has been designed. The structure optimization was achieved by theoretical analysis and numerical calculation. The simulation shows that, with the frequency varying from 1.3 to 1.6 GHz, the gain increases from -2.0 to 0.8 dBi linearly. The maximal radiation direction is in the axial direction of the antennas physical structure. The gain and the radiation pattern of the antenna were calibrated with the Agilent E8362B network analyzer, and the calibrated results agree with the simulation ones. The gain increases from -2.3 to 1.2 dBi in the same frequency range. The width of the radiation beam is more than 60, and the axial ratio is more than 35 dB.The results show that the design can satisfy the requirements of low gain and small size for the L-band high power microwave measurement.
In order to reduce the size and gain of the high power microwave measurement receiving antenna, a small-sized expanded coaxial line antenna operating at L-band has been designed. The structure optimization was achieved by theoretical analysis and numerical calculation. The simulation shows that, with the frequency varying from 1.3 to 1.6 GHz, the gain increases from -2.0 to 0.8 dBi linearly. The maximal radiation direction is in the axial direction of the antennas physical structure. The gain and the radiation pattern of the antenna were calibrated with the Agilent E8362B network analyzer, and the calibrated results agree with the simulation ones. The gain increases from -2.3 to 1.2 dBi in the same frequency range. The width of the radiation beam is more than 60, and the axial ratio is more than 35 dB.The results show that the design can satisfy the requirements of low gain and small size for the L-band high power microwave measurement.
2012,
24: 1603-1607.
Abstract:
Proton beam writing（PBW） is a direct-writing technique that uses a highly focused MeV proton beam to pattern structures of micro- or nano-dimensions in a suitable resist material. The PBW instrumentation was established on the scanning proton microprobe beamline of Key Laboratory of Nuclear Analysis Techniques (Shanghai Institute of Applied Physics, CAS). The study of spin-coating resist layer and developing technology was carried out. A Haibao outline and a double-rectangular micro-structure were fabricated on the positive resist layers; the parallel lines and a crisscross micro-structure were fabricated on the negative resist layers.
Proton beam writing（PBW） is a direct-writing technique that uses a highly focused MeV proton beam to pattern structures of micro- or nano-dimensions in a suitable resist material. The PBW instrumentation was established on the scanning proton microprobe beamline of Key Laboratory of Nuclear Analysis Techniques (Shanghai Institute of Applied Physics, CAS). The study of spin-coating resist layer and developing technology was carried out. A Haibao outline and a double-rectangular micro-structure were fabricated on the positive resist layers; the parallel lines and a crisscross micro-structure were fabricated on the negative resist layers.
2012,
24: 1608-1610.
Abstract:
This article introduces two experiments: one is the lifetime test of organic light-emitting device(OLED) packaged by UV cured epoxy resin in a high vacuum environment after being unpackaged, the other is the lifetime test of unpackaged OLED in atmospheric condition using the same parameters. The results of experiments show that the accelerating lifetime of unpackaged OLED in a high vacuum environment is 1675 h while that of packaged OLED in atmospheric condition is 1224 h, which indicates that the lifetime of OLED in a high vacuum environment has an obvious improvement. This phenomenon proves that the penetration of water vapor and oxygen through materials packaged by UV cured epoxy resin are significant factors influencing the lifetime of OLED packaged by UV cured epoxy resin. Inspiratory films in OLEDs cannot totally absorb water vapor and oxygen penetrating into the devices. Besides water vapor and oxygen, there are some other important factors influencing the lifetime of OLEDs.
This article introduces two experiments: one is the lifetime test of organic light-emitting device(OLED) packaged by UV cured epoxy resin in a high vacuum environment after being unpackaged, the other is the lifetime test of unpackaged OLED in atmospheric condition using the same parameters. The results of experiments show that the accelerating lifetime of unpackaged OLED in a high vacuum environment is 1675 h while that of packaged OLED in atmospheric condition is 1224 h, which indicates that the lifetime of OLED in a high vacuum environment has an obvious improvement. This phenomenon proves that the penetration of water vapor and oxygen through materials packaged by UV cured epoxy resin are significant factors influencing the lifetime of OLED packaged by UV cured epoxy resin. Inspiratory films in OLEDs cannot totally absorb water vapor and oxygen penetrating into the devices. Besides water vapor and oxygen, there are some other important factors influencing the lifetime of OLEDs.
2012,
24: 1611-1614.
Abstract:
The impacts of effective aperture size and beam incident angle on the aberration correction ability of a 20-actuator bimorph deformable mirror whose clear aperture is 30 mm are numerically analyzed based on measured influence functions. Numerical simulations show that, when the effective aperture is 16 mm, the deformable mirror can correct aberrations well. The increase in the beam incident angle lowers both the correction accuracy and amplitude. However, if the incident angle is limited within 25, the impact of beam incident angle is not obvious.
The impacts of effective aperture size and beam incident angle on the aberration correction ability of a 20-actuator bimorph deformable mirror whose clear aperture is 30 mm are numerically analyzed based on measured influence functions. Numerical simulations show that, when the effective aperture is 16 mm, the deformable mirror can correct aberrations well. The increase in the beam incident angle lowers both the correction accuracy and amplitude. However, if the incident angle is limited within 25, the impact of beam incident angle is not obvious.
2012,
24: 1615-1618.
Abstract:
The physical mechanism of field emission was analyzed. The launch conditions of field emission in three-dimensional Yee grid model were deduced and implemented, and the Pade grid algorithm was used to encrypt the cutting-edge grid. The current-voltage relationship and the 3/2 power of the space charge limited flow at high voltage were obtained for a wedge-shaped cathode field emission model, which verify the correctness of simulation. In order to deal with the great amount of computation due to large particle number and huge grid, the message passing interface (MPI) was used, and a more than 3.0 parallel speedup was obtained.
The physical mechanism of field emission was analyzed. The launch conditions of field emission in three-dimensional Yee grid model were deduced and implemented, and the Pade grid algorithm was used to encrypt the cutting-edge grid. The current-voltage relationship and the 3/2 power of the space charge limited flow at high voltage were obtained for a wedge-shaped cathode field emission model, which verify the correctness of simulation. In order to deal with the great amount of computation due to large particle number and huge grid, the message passing interface (MPI) was used, and a more than 3.0 parallel speedup was obtained.
2012,
24: 1619-1623.
Abstract:
The theoretical formula of gas permeation acceleration factor was derived for barrier materials under different gas temperature and pressure. The theoretical calculation results are consistent with the experimental results (in the literature). The permeability of various gases，including water vapor, oxygen and carbon dioxide, through polyethylene terephthalate (PET) plastic and epoxy resin, was measured by mass spectrometry under accelerated conditions. At normal temperature and pressure, the gas permeabilities of PET plastic film with a thickness of 0.155 mm are 1.110-2 g/(m2d), 1.610-4 cm3/(m2d), 810-4 cm3/(m2d), and the gas permeabilities of epoxy resin film with a thickness of 0.065 mm are 1.710-2 g/(m2d), 3.510-5 cm3/(m2d), 5.510-5 cm3/(m2d).
The theoretical formula of gas permeation acceleration factor was derived for barrier materials under different gas temperature and pressure. The theoretical calculation results are consistent with the experimental results (in the literature). The permeability of various gases，including water vapor, oxygen and carbon dioxide, through polyethylene terephthalate (PET) plastic and epoxy resin, was measured by mass spectrometry under accelerated conditions. At normal temperature and pressure, the gas permeabilities of PET plastic film with a thickness of 0.155 mm are 1.110-2 g/(m2d), 1.610-4 cm3/(m2d), 810-4 cm3/(m2d), and the gas permeabilities of epoxy resin film with a thickness of 0.065 mm are 1.710-2 g/(m2d), 3.510-5 cm3/(m2d), 5.510-5 cm3/(m2d).
2012,
24: 1624-1628.
Abstract:
The paper introduces the design of driving circuit, reset circuit, download circuit, interface circuit and driving programs of the full-color passive OLED(organic light emitting device) module in the display system. The system adopts the LPC2138, family of ARM7-core, to control the OLED module. The data and control signals are provided by LPC2138 in order to realize a resolution of 128128, 65103 dynamic full-color display. Experiment results show that the system can display red, green, blue and full-color pictures, provide a low-cost, low-power and single-chip solution for small sized OLEDs.
The paper introduces the design of driving circuit, reset circuit, download circuit, interface circuit and driving programs of the full-color passive OLED(organic light emitting device) module in the display system. The system adopts the LPC2138, family of ARM7-core, to control the OLED module. The data and control signals are provided by LPC2138 in order to realize a resolution of 128128, 65103 dynamic full-color display. Experiment results show that the system can display red, green, blue and full-color pictures, provide a low-cost, low-power and single-chip solution for small sized OLEDs.
2012,
24: 1629-1632.
Abstract:
The paper studies the rapid thermal annealing(RTA) effect on Cu(In, Ga)Se2 (CIGS) solar cells at different annealing temperatures by photoluminescence(PL). Continuous RTA was applied to CIGS solar cells to study annealing effect on film defects. Seven peaks exist in CIGS PL spectra: two in visible light region, the others in infrared region. When the temperature is relatively low, RTA treatment can improve the film quality because of the decrease of defects and the increase of carriers. High temperature RTA treatment will lead to elements diffusion between layers and change of stoichiometric ratio, increasing interface states and decreasing the bandgap of absorber layer, and thus destroy the device structures.
The paper studies the rapid thermal annealing(RTA) effect on Cu(In, Ga)Se2 (CIGS) solar cells at different annealing temperatures by photoluminescence(PL). Continuous RTA was applied to CIGS solar cells to study annealing effect on film defects. Seven peaks exist in CIGS PL spectra: two in visible light region, the others in infrared region. When the temperature is relatively low, RTA treatment can improve the film quality because of the decrease of defects and the increase of carriers. High temperature RTA treatment will lead to elements diffusion between layers and change of stoichiometric ratio, increasing interface states and decreasing the bandgap of absorber layer, and thus destroy the device structures.
2012,
24: 1633-1637.
Abstract:
The article describes a highly effective alternated red-emitting organic light-emitting diode(OLED), which uses 9,9-spirobifluoren-2-yl-diphenyl-phosphine oxide (SPPO1) with high triple state as the host and hole-blocking layer and Bis(1-phenyl-isoquinoline) (Acetylacetonato)iridium(III) (Ir(pig)2(acac)) as objected emitting materials. The energy of SPPO1 in the luminescent layer, is respectively transferred by a Frster or Dexter process to the single state or triple state of Ir(pig)2(acac) and then the device shows red light emitting. The improvements in OLED performance and the tunability of emitting light are realized through regulating the ratio of Ir(pig)2(acac).
The article describes a highly effective alternated red-emitting organic light-emitting diode(OLED), which uses 9,9-spirobifluoren-2-yl-diphenyl-phosphine oxide (SPPO1) with high triple state as the host and hole-blocking layer and Bis(1-phenyl-isoquinoline) (Acetylacetonato)iridium(III) (Ir(pig)2(acac)) as objected emitting materials. The energy of SPPO1 in the luminescent layer, is respectively transferred by a Frster or Dexter process to the single state or triple state of Ir(pig)2(acac) and then the device shows red light emitting. The improvements in OLED performance and the tunability of emitting light are realized through regulating the ratio of Ir(pig)2(acac).
2012,
24: 1638-1640.
Abstract:
The heat dissipating area of light emitting diode (LED) is calculated and the model of LED heat dissipation with platy cooling fins is established and simulated by ANSYS. When the ratio of fin spacing and fin thickness is 3∶2 or the ratio of fin thickness and base thickness is 1∶1, the heat dissipating performance of LED is the best, on condition that other parameters are fixed. With the increase in the number of fins and the height of fins, the heat dissipation performance improves.
The heat dissipating area of light emitting diode (LED) is calculated and the model of LED heat dissipation with platy cooling fins is established and simulated by ANSYS. When the ratio of fin spacing and fin thickness is 3∶2 or the ratio of fin thickness and base thickness is 1∶1, the heat dissipating performance of LED is the best, on condition that other parameters are fixed. With the increase in the number of fins and the height of fins, the heat dissipation performance improves.
2012,
24: 1641-1644.
Abstract:
The theoretical formula of phase-shift coefficient of piezoelectric fiber optic phase modulator is introduced, and a measuring method of the phase-shift coefficient is suggested based on Youngs two-slit interference principle. The feasibility of this measuring method is analyzed, and then verified by experiments. A phase modulator device based on piezoelectric ceramic ring is developed, and the phase-shift coefficient is tested which is consistent with the theoretical result. A experiment of phase locking of two beams is carried out with the self-developed piezoelectric fiber optic phase modulator, and coherent beam combination in far-field is achieved successfully. The fringe visibility in phase-locking state is up to 43%, compared with 3% with phase-locking off.
The theoretical formula of phase-shift coefficient of piezoelectric fiber optic phase modulator is introduced, and a measuring method of the phase-shift coefficient is suggested based on Youngs two-slit interference principle. The feasibility of this measuring method is analyzed, and then verified by experiments. A phase modulator device based on piezoelectric ceramic ring is developed, and the phase-shift coefficient is tested which is consistent with the theoretical result. A experiment of phase locking of two beams is carried out with the self-developed piezoelectric fiber optic phase modulator, and coherent beam combination in far-field is achieved successfully. The fringe visibility in phase-locking state is up to 43%, compared with 3% with phase-locking off.
2012,
24: 1645-1647.
Abstract:
Organic thin film solar cells based on flexible substrate were studied, which were prepared by using poly (3, 4-ethylenedioxythiophene): poly (4-styrenesulfonic acid) (PEDOT: PSS) as an anode modification layer, poly (2-methoxy, 5-(2-ethylhexyloxy)-1, 4-phenylene vinylene) (MEH-PPV) as a donor layer and fullerene (C60) as an acceptor layer. The results show that, the anode modification layer increases the short-circuit current density, open-circuit voltage, fill factor and power conversion efficiency of cells apparently although it may block the light absorption. The thickness of the acceptor layer also influences the cells performance. A maximum power conversion efficiency of 1.29% has been achieved by employing 90 nm-thick MEH-PPV layer.
Organic thin film solar cells based on flexible substrate were studied, which were prepared by using poly (3, 4-ethylenedioxythiophene): poly (4-styrenesulfonic acid) (PEDOT: PSS) as an anode modification layer, poly (2-methoxy, 5-(2-ethylhexyloxy)-1, 4-phenylene vinylene) (MEH-PPV) as a donor layer and fullerene (C60) as an acceptor layer. The results show that, the anode modification layer increases the short-circuit current density, open-circuit voltage, fill factor and power conversion efficiency of cells apparently although it may block the light absorption. The thickness of the acceptor layer also influences the cells performance. A maximum power conversion efficiency of 1.29% has been achieved by employing 90 nm-thick MEH-PPV layer.
2012,
24: 1648-1650.
Abstract:
One-dimensional ZnO nanowires were fabricated by using the hydrothermal technique. By changing the orientation of the ZnO nanowires (horizontal and vertical) and using differentp-type semiconductor materials, hybrid organic-ZnO nanowire photodiodes were prepared. Related characteristics of the photodiodes were investigated. When a forward voltage is applied, the photocurrent is greater under illumination than that without illumination. When a reverse voltage is applied, the result is opposite. The photocurrent is also related to the light intensity on photodiodes. The greater the light intensity is, the greater the current is. Key words:
One-dimensional ZnO nanowires were fabricated by using the hydrothermal technique. By changing the orientation of the ZnO nanowires (horizontal and vertical) and using differentp-type semiconductor materials, hybrid organic-ZnO nanowire photodiodes were prepared. Related characteristics of the photodiodes were investigated. When a forward voltage is applied, the photocurrent is greater under illumination than that without illumination. When a reverse voltage is applied, the result is opposite. The photocurrent is also related to the light intensity on photodiodes. The greater the light intensity is, the greater the current is. Key words:
2012,
24: 1651-1655.
Abstract:
Forty-seven pieces of slab gain mediums were measured using this diagnostic method and the results show that the wavefront aberrations of slab gain mediums are affected by the processes like coating. The measurement results were classified by PV (peak to valley) values of static wavefront aberrations. The maximum PV value is more than 5 m for the measured samples and only 4.1% of the samples have PV values less than 1 m. Some slab gain mediums were selected and connected in series like in a slab laser system. The measurement results reveal that if the wavefront aberrations of the two gain mediums in series can complement each other, the static aberrations of the laser system can be reduced.
Forty-seven pieces of slab gain mediums were measured using this diagnostic method and the results show that the wavefront aberrations of slab gain mediums are affected by the processes like coating. The measurement results were classified by PV (peak to valley) values of static wavefront aberrations. The maximum PV value is more than 5 m for the measured samples and only 4.1% of the samples have PV values less than 1 m. Some slab gain mediums were selected and connected in series like in a slab laser system. The measurement results reveal that if the wavefront aberrations of the two gain mediums in series can complement each other, the static aberrations of the laser system can be reduced.
2012,
24: 1656-1662.
Abstract:
In order to measure laser power accurately under oblique incidence, a correction method for power responsivity of array detectors according to incidence angle is adopted. The expressions of directional cosines and incidence angle depending on the position of laser source, and the position and attitude angle of array detectors are derived. Measurement uncertainties of directional cosines, incidence angle and correction factor of array detectors are derived. The measurement uncertainty expression of laser power is then derived based on the expression of laser power. Therefore the measurement method of laser power and the evaluation method of the power measurement uncertainty under oblique incidence are completely developed. For an example with typical parameters, the power measurement uncertainty under oblique incidence is calculated. The result shows that it is valid to correct the measured laser power for the decrement of measurement uncertainty. Key words:
In order to measure laser power accurately under oblique incidence, a correction method for power responsivity of array detectors according to incidence angle is adopted. The expressions of directional cosines and incidence angle depending on the position of laser source, and the position and attitude angle of array detectors are derived. Measurement uncertainties of directional cosines, incidence angle and correction factor of array detectors are derived. The measurement uncertainty expression of laser power is then derived based on the expression of laser power. Therefore the measurement method of laser power and the evaluation method of the power measurement uncertainty under oblique incidence are completely developed. For an example with typical parameters, the power measurement uncertainty under oblique incidence is calculated. The result shows that it is valid to correct the measured laser power for the decrement of measurement uncertainty. Key words:
2012,
24: 1663-1666.
Abstract:
A laser beam cleanup system based on a 37-element bimorph deformable mirror (DM) is presented, to correct the wavefront aberrations of slab laser amplifier and improve the output laser beam quality. The strip-shaped laser beam is expanded by a cylinder mirrors expander to match with the bimorph DM. The stochastic parallel gradient descent (SPGD) algorithm is utilized to optimize the surface of bimorph DM. The normalized power in the bucket (NPIB) of laser beam is enhanced by 2-3 times, after the wave-front aberrations are corrected.
A laser beam cleanup system based on a 37-element bimorph deformable mirror (DM) is presented, to correct the wavefront aberrations of slab laser amplifier and improve the output laser beam quality. The strip-shaped laser beam is expanded by a cylinder mirrors expander to match with the bimorph DM. The stochastic parallel gradient descent (SPGD) algorithm is utilized to optimize the surface of bimorph DM. The normalized power in the bucket (NPIB) of laser beam is enhanced by 2-3 times, after the wave-front aberrations are corrected.
2012,
24: 1667-1671.
Abstract:
Compared with conventional Brillouin optical time-domain analyzer (BOTDA), the BOTDA based on Raman amplification allows longer sensing range, higher signal-to-noise ratio and higher measurement accuracy. However, the non-local effect induced by pump depletion significantly restricts the probe optical power injected to sensing fiber, thereby limiting the further extension for sensing distance. In this paper, the coupled equations including the interaction of probe light, Brillouin and Raman pumps are applied to the study on the non-local characteristics of BOTDA based on Raman amplification. The results show that, the system error induced by non-local effect worsens with increased powers of probe wave and Raman pump. The frequency-division-multiplexing (cascading the fibers with various Brillouin frequency shifts) and time-division- multiplexing (modulating both of the Brillouin pump and probe lights) technologies are efficient approaches to suppress the non-local effect, through shortening the effective interaction range between Brillouin pump and probe lights.
Compared with conventional Brillouin optical time-domain analyzer (BOTDA), the BOTDA based on Raman amplification allows longer sensing range, higher signal-to-noise ratio and higher measurement accuracy. However, the non-local effect induced by pump depletion significantly restricts the probe optical power injected to sensing fiber, thereby limiting the further extension for sensing distance. In this paper, the coupled equations including the interaction of probe light, Brillouin and Raman pumps are applied to the study on the non-local characteristics of BOTDA based on Raman amplification. The results show that, the system error induced by non-local effect worsens with increased powers of probe wave and Raman pump. The frequency-division-multiplexing (cascading the fibers with various Brillouin frequency shifts) and time-division- multiplexing (modulating both of the Brillouin pump and probe lights) technologies are efficient approaches to suppress the non-local effect, through shortening the effective interaction range between Brillouin pump and probe lights.
2012,
24: 1672-1676.
Abstract:
With the organic polymer ridge waveguide as the research object, the polarization characteristic of symmetric ridge waveguides with different ridge heights, ridge widths and core thicknesses were systematically analyzed by a semi-vector finite-difference beam propagation method(FD-BPM). Furthermore, the polarization characteristics of asymmetric ridge waveguides were analyzed, and the influence of the shorter side width of the core to the polarization characteristic is studied. The result shows that the introduction of asymmetric ridge structure has a minor effect to the polarization characteristic, and the birefringence decreases along with the reduction of the shorter side width of the core. The birefringence of the asymmetric ridge waveguide can be controlled in an acceptable range when the ridge height is 1.3 m and the shorter side width of the core is 2.0 m.
With the organic polymer ridge waveguide as the research object, the polarization characteristic of symmetric ridge waveguides with different ridge heights, ridge widths and core thicknesses were systematically analyzed by a semi-vector finite-difference beam propagation method(FD-BPM). Furthermore, the polarization characteristics of asymmetric ridge waveguides were analyzed, and the influence of the shorter side width of the core to the polarization characteristic is studied. The result shows that the introduction of asymmetric ridge structure has a minor effect to the polarization characteristic, and the birefringence decreases along with the reduction of the shorter side width of the core. The birefringence of the asymmetric ridge waveguide can be controlled in an acceptable range when the ridge height is 1.3 m and the shorter side width of the core is 2.0 m.
2012,
24: 1677-1682.
Abstract:
A numerical simulation model of coherent combination of three rectangular beams was established. The relationship for one rectangular beam and the combination of three rectangular beams, between the beam quality factor (beta factor) and the Zernike wavefront aberrations of the first twenty-one orders was obtained by numerical calculation through fast Fourier transform (FFT). The formulas of beta factor and wavefront aberration were obtained. Fitting coefficients of one beam and three-beam combination were compared and the affecting factors were analyzed. It is found that the fitting coefficient generally augments with the order of Zernike wavefront aberrations increasing. Key words: 。
A numerical simulation model of coherent combination of three rectangular beams was established. The relationship for one rectangular beam and the combination of three rectangular beams, between the beam quality factor (beta factor) and the Zernike wavefront aberrations of the first twenty-one orders was obtained by numerical calculation through fast Fourier transform (FFT). The formulas of beta factor and wavefront aberration were obtained. Fitting coefficients of one beam and three-beam combination were compared and the affecting factors were analyzed. It is found that the fitting coefficient generally augments with the order of Zernike wavefront aberrations increasing. Key words: 。
2012,
24: 1683-1686.
Abstract:
In order to meet the pump power density requirements of room-temperature Yb: YAG laser amplifier, a coupling system of high contraction coefficient has been designed. Laser diode (LD) arrays of 80 kW output power are arranged to be spherical. Orthogonal cylindrical lenses and a hollow duct are used for pump-coupling according to luminescence properties of LD. The contraction coefficient is up to 86∶1. Simulations show that the coupling efficiency of the coupling system depends weakly on the reflectivity of the reflectors of the hollow duct. The pump light can transport over a distance of at least 8.5 mm with its shape maintained. The coupling system can meet the requirements of the end-pumped room-temperature Yb:YAG slab amplifier.
In order to meet the pump power density requirements of room-temperature Yb: YAG laser amplifier, a coupling system of high contraction coefficient has been designed. Laser diode (LD) arrays of 80 kW output power are arranged to be spherical. Orthogonal cylindrical lenses and a hollow duct are used for pump-coupling according to luminescence properties of LD. The contraction coefficient is up to 86∶1. Simulations show that the coupling efficiency of the coupling system depends weakly on the reflectivity of the reflectors of the hollow duct. The pump light can transport over a distance of at least 8.5 mm with its shape maintained. The coupling system can meet the requirements of the end-pumped room-temperature Yb:YAG slab amplifier.
2012,
24: 1687-1690.
Abstract:
The paper investigates the annular lapping process of large-aperture reflective component. A 610 mm440 mm85 mm reflective component was processed by a lapping machine with a 4 m-diameter lapping disk. In order to improve the surface flatness of the optical component， the rotating speeds and locations of the conditioner and the workpiece ring，and the groove shape on the asphalt plate were optimized. The surface flatness converse more efficiently, with the best value of /6(=632.8 nm), after optimization. Thus annular lapping is suitable for processing large-aperture optical components.
The paper investigates the annular lapping process of large-aperture reflective component. A 610 mm440 mm85 mm reflective component was processed by a lapping machine with a 4 m-diameter lapping disk. In order to improve the surface flatness of the optical component， the rotating speeds and locations of the conditioner and the workpiece ring，and the groove shape on the asphalt plate were optimized. The surface flatness converse more efficiently, with the best value of /6(=632.8 nm), after optimization. Thus annular lapping is suitable for processing large-aperture optical components.
2012,
24: 1691-1694.
Abstract:
An intracavity adaptive optics system is presented for optimizing beam intensity profiles of an flashlamp-pumped Nd:YAG laser. The rear mirror of the laser is replaced by a 20-element bimorph deformable mirror controlled by a stochastic parallel gradient decent algorithm aiming at achieving more concentrated power distribution in the far-field. Experimental results demonstrate that this system effectively transforms the far-field intensity distribution with multiple lobes into a single bright lobe within only about 20 s, and the peak intensity is improved up to 6 times. The output power can be increased from 0.006-0.051 W to 0.330 W when large misalignment exists. The effectiveness of the proposed system is demonstrated by the above experimental results.
An intracavity adaptive optics system is presented for optimizing beam intensity profiles of an flashlamp-pumped Nd:YAG laser. The rear mirror of the laser is replaced by a 20-element bimorph deformable mirror controlled by a stochastic parallel gradient decent algorithm aiming at achieving more concentrated power distribution in the far-field. Experimental results demonstrate that this system effectively transforms the far-field intensity distribution with multiple lobes into a single bright lobe within only about 20 s, and the peak intensity is improved up to 6 times. The output power can be increased from 0.006-0.051 W to 0.330 W when large misalignment exists. The effectiveness of the proposed system is demonstrated by the above experimental results.
2012,
24: 1695-1699.
Abstract:
Experiments on magnetorheological finishing (MRF) were carried out to remove the subsurface defect (SSD) layer left by conventional polishing. The simulation and experiment results show that, the scanning interval of MRF will lead to the mid-spatial frequency error of corresponding frequency, the instability of the polishing spot will leave the mid-spatial frequency error of uncertain frequency, and an approximately linear correlation is found between the depth of removal and the peak value of power spectral density (PSD) of processed components. With MRF as the method to remove the SSD layer, the quality of processed components concerning the mid-spatial frequency is greatly affected by the processing settings. If a thick SSD layer is left by an inappropriate prior polishing, the PSD after MRF will exceed the limit.
Experiments on magnetorheological finishing (MRF) were carried out to remove the subsurface defect (SSD) layer left by conventional polishing. The simulation and experiment results show that, the scanning interval of MRF will lead to the mid-spatial frequency error of corresponding frequency, the instability of the polishing spot will leave the mid-spatial frequency error of uncertain frequency, and an approximately linear correlation is found between the depth of removal and the peak value of power spectral density (PSD) of processed components. With MRF as the method to remove the SSD layer, the quality of processed components concerning the mid-spatial frequency is greatly affected by the processing settings. If a thick SSD layer is left by an inappropriate prior polishing, the PSD after MRF will exceed the limit.
2012,
24: 1700-1704.
Abstract:
The cone pinhole that is a new structure pinhole is used for spatial filtering in high solid-state laser system. Its smooth inner surface will reflect the unwanted light to prevent plasma closure that easily happens in high energy running. The comparison between the cone pinhole and the washer pinhole shows that the cone one performs better under high energy running. The cone pinhole can avoid the plasma closure effect more efficiently. Combined with the adaptive optical technology, it ensures that the beam path is unobstructed. The use of seven-order cone pinholes in spatial filters makes the high energy output more stable, and the output energy reaches 7988 J, which means the single beam power density reaches 6.2 J/cm2. The method for designing the cone pinhole is also presented.
The cone pinhole that is a new structure pinhole is used for spatial filtering in high solid-state laser system. Its smooth inner surface will reflect the unwanted light to prevent plasma closure that easily happens in high energy running. The comparison between the cone pinhole and the washer pinhole shows that the cone one performs better under high energy running. The cone pinhole can avoid the plasma closure effect more efficiently. Combined with the adaptive optical technology, it ensures that the beam path is unobstructed. The use of seven-order cone pinholes in spatial filters makes the high energy output more stable, and the output energy reaches 7988 J, which means the single beam power density reaches 6.2 J/cm2. The method for designing the cone pinhole is also presented.
2012,
24: 1705-1708.
Abstract:
This paper introduces an FPGA-based all-digital phase-locked loop(ADPLL) control system for phase-shift laser ranging. The system can improve the accuracy of the phase frequency detector and is immune to the effects of temperature and voltage, thus significantly reducing the frequency error in phase detection of phase-shift laser ranging. It consists of a digital phase detector, a digital filter and a digitally controlled oscillator. When the reference signal generated inside the FPGA is 40 Hz, the sampling period is 0.025 s and the output reaches saturation (about 5 V) after approximately 300 ms. The ADPLL control system avoids the problems often encountered by analog circuits, like incomplete transmission, parasite, temperature fluctuations and aging. Moreover, it is easy to test and reset.
This paper introduces an FPGA-based all-digital phase-locked loop(ADPLL) control system for phase-shift laser ranging. The system can improve the accuracy of the phase frequency detector and is immune to the effects of temperature and voltage, thus significantly reducing the frequency error in phase detection of phase-shift laser ranging. It consists of a digital phase detector, a digital filter and a digitally controlled oscillator. When the reference signal generated inside the FPGA is 40 Hz, the sampling period is 0.025 s and the output reaches saturation (about 5 V) after approximately 300 ms. The ADPLL control system avoids the problems often encountered by analog circuits, like incomplete transmission, parasite, temperature fluctuations and aging. Moreover, it is easy to test and reset.
2012,
24: 1709-1714.
Abstract:
A sensor based on conjugate principle has been designed for matching the light beams and the target in inertial confinement fusion. It can avoid the direct illumination of the simulation collimating light on the target under test in targeting processes. This paper introduces the optical and mechanical design of the sensor, according to its design functions and working principle. The resolution of the optical images obtained in experiments reaches 6 m and the beam-target matching accuracy is 8.8 m. The sensor has been successfully applied to the Shenguang-Ⅲ facility. Statistical analyses of the four-hole CH target images derived with pinhole camera shows that the targeting accuracy of the facility is better than 25 m, satisfying the design requirements.
A sensor based on conjugate principle has been designed for matching the light beams and the target in inertial confinement fusion. It can avoid the direct illumination of the simulation collimating light on the target under test in targeting processes. This paper introduces the optical and mechanical design of the sensor, according to its design functions and working principle. The resolution of the optical images obtained in experiments reaches 6 m and the beam-target matching accuracy is 8.8 m. The sensor has been successfully applied to the Shenguang-Ⅲ facility. Statistical analyses of the four-hole CH target images derived with pinhole camera shows that the targeting accuracy of the facility is better than 25 m, satisfying the design requirements.
2012,
24: 1715-1717.
Abstract:
Two-wavelength clock reshaping via four-wave mixing has been studied by simulation. A pump which is shared by the two channels of clock signals is coupled into the highly nonlinear fiber with a probe. Interchannel crosstalk of four-wave mixing can be avoided when we add a time delay into one channel to separate the two clocks. Two idles generated via four-wave mixing are the reshaped clock. The relation between duty cycles of the input clocks and the quality of reshaped clocks has been studied. The relation of the relative amplitude jitters between input clock signal and output clock signal under optimum duty cycles has also been investigated. When the duty cycles increase, the quality of reshaped clocks improves and then deteriorates. At the optimum duty cycle of 0.14, the relative amplitude jitters fall from 13.934 9% and 13.958 6% to 2.03% and 2.12%, which proves the method is feasible.
Two-wavelength clock reshaping via four-wave mixing has been studied by simulation. A pump which is shared by the two channels of clock signals is coupled into the highly nonlinear fiber with a probe. Interchannel crosstalk of four-wave mixing can be avoided when we add a time delay into one channel to separate the two clocks. Two idles generated via four-wave mixing are the reshaped clock. The relation between duty cycles of the input clocks and the quality of reshaped clocks has been studied. The relation of the relative amplitude jitters between input clock signal and output clock signal under optimum duty cycles has also been investigated. When the duty cycles increase, the quality of reshaped clocks improves and then deteriorates. At the optimum duty cycle of 0.14, the relative amplitude jitters fall from 13.934 9% and 13.958 6% to 2.03% and 2.12%, which proves the method is feasible.
2012,
24: 1718-1722.
Abstract:
High frequency spatial modulation induced by Fresnel diffraction of broadband nanosecond chirped laser pulse were studied. It shows that the hundreds-nm broadband pulse has some effects on Fresnel diffraction, while the tens-nm one has hardly any. Moreover, three B-integral expressions and the fast gain frequency of tens-nm broadband nanosecond chirped laser pulse were studied, and compared with the nonlinar experiments of narrowband pulse and chirped pulse stacking on Technical Intepration Lines facility. The results reveal that, the maximal B-integral or the weighted average B-integral can better reflect the nonlinear self-focusing phenomenon, and there are no distinct differences between the narrowband and the tens-nm broadband nanosecond laser pulses with respect to the fast gain frequency.
High frequency spatial modulation induced by Fresnel diffraction of broadband nanosecond chirped laser pulse were studied. It shows that the hundreds-nm broadband pulse has some effects on Fresnel diffraction, while the tens-nm one has hardly any. Moreover, three B-integral expressions and the fast gain frequency of tens-nm broadband nanosecond chirped laser pulse were studied, and compared with the nonlinar experiments of narrowband pulse and chirped pulse stacking on Technical Intepration Lines facility. The results reveal that, the maximal B-integral or the weighted average B-integral can better reflect the nonlinear self-focusing phenomenon, and there are no distinct differences between the narrowband and the tens-nm broadband nanosecond laser pulses with respect to the fast gain frequency.
2012,
24: 1723-1726.
Abstract:
The paper presents the solutions of coupled-waves equations of degenerate four-wave mixing (DFWM) numerically. The results show that the power increase of pump wave can decrease the period of energy interchange of pump and anti-Stokes waves, and the power transfer relationship of pump and anti-Stokes waves in specific distances can be used for all-optical signal amplitude reshaping. The all-optical signal amplitude reshaping principle is explained from this point of view, and an all-optical signal reshaping system is designed accordingly. The system is tested through the eye diagrams of input and output signals, extinction ratio (ER) and Q-factor by simulating. It improves the ER and Q-factor from 9.46 dB to 30.4 dB and 15.95 to 180.4 respectively.
The paper presents the solutions of coupled-waves equations of degenerate four-wave mixing (DFWM) numerically. The results show that the power increase of pump wave can decrease the period of energy interchange of pump and anti-Stokes waves, and the power transfer relationship of pump and anti-Stokes waves in specific distances can be used for all-optical signal amplitude reshaping. The all-optical signal amplitude reshaping principle is explained from this point of view, and an all-optical signal reshaping system is designed accordingly. The system is tested through the eye diagrams of input and output signals, extinction ratio (ER) and Q-factor by simulating. It improves the ER and Q-factor from 9.46 dB to 30.4 dB and 15.95 to 180.4 respectively.
2012,
24: 1727-1731.
Abstract:
This paper reviews the authors recent work on cascaded nonlinear processes, revealing that cascaded nonlinear processes can lead to energy transfer between different wavelengths and spectral broadening caused by the second-order cascaded processes can provide the seed for a broadband conical emission. It further shows the relation between the input fundamental wavelength and the energy transfer effect caused by the supercontinuum generation: higher conversion efficiency is got when the input wavelength approaches the phase-matching wavelength. The significant fundamental polarization modulation caused by second order cascaded nonlinear processes is also investigated.
This paper reviews the authors recent work on cascaded nonlinear processes, revealing that cascaded nonlinear processes can lead to energy transfer between different wavelengths and spectral broadening caused by the second-order cascaded processes can provide the seed for a broadband conical emission. It further shows the relation between the input fundamental wavelength and the energy transfer effect caused by the supercontinuum generation: higher conversion efficiency is got when the input wavelength approaches the phase-matching wavelength. The significant fundamental polarization modulation caused by second order cascaded nonlinear processes is also investigated.
2012,
24: 1732-1736.
Abstract:
The unidirectional master-slave scheme for generating chaos is demonstrated, which consists of a distributed feedback laser and a semiconductor ring laser(SRL). The SRL, under suitable bias current, has a chaotic output due to an optical injection from the master laser with suitable detuning frequency and injection coefficient. By numerical simulation based on the rate equations of the semiconductor ring laser subjected to an external injection, bifurcation diagrams are derived, of the parameters of interest: the detuning frequency, injection coefficient and the bias current of the SRL. The result shows that, high-quality chaos with flat power spectrum can be generated in the SRL when the detuning frequency is 3.9 GHz, the injection coefficient is 0.07 and the bias current of the SRL is 81 mA.
The unidirectional master-slave scheme for generating chaos is demonstrated, which consists of a distributed feedback laser and a semiconductor ring laser(SRL). The SRL, under suitable bias current, has a chaotic output due to an optical injection from the master laser with suitable detuning frequency and injection coefficient. By numerical simulation based on the rate equations of the semiconductor ring laser subjected to an external injection, bifurcation diagrams are derived, of the parameters of interest: the detuning frequency, injection coefficient and the bias current of the SRL. The result shows that, high-quality chaos with flat power spectrum can be generated in the SRL when the detuning frequency is 3.9 GHz, the injection coefficient is 0.07 and the bias current of the SRL is 81 mA.
2012,
24: 1737-1740.
Abstract:
This paper demonstrates several factors that affect the signal-to-noise ratio(SNR) improvement ability and the energy conversion efficiency of nonlinear Sagnac interferometry. The efficiency can be improved by controlling the spatial distribution of pulse and the transmittance of attenuator. The SNR improvement ability is related to the SNR of input pulse: higher input pulse SNR enhances the SNR improvement. The experimental platform was established on SILEX-Ⅰ laser facility. The ultra-short pulse from 3 TW compressor was attenuated and sent into the Sagnac loop. The nonlinear medium was a 5 cm long fused silica material and the attenuator transmittance was 55%. When the input pulse energy is 6.6 mJ, the pulse SNR is improved from 10-6 to 10-7 by third-order autocorrelator. The energy of the output pulse is 1.6 mJ, with efficiency about 24%. This method has no limit to the beam diameter, and thus can be used for short-pulse SNR enhancement in the large energy conditions.
This paper demonstrates several factors that affect the signal-to-noise ratio(SNR) improvement ability and the energy conversion efficiency of nonlinear Sagnac interferometry. The efficiency can be improved by controlling the spatial distribution of pulse and the transmittance of attenuator. The SNR improvement ability is related to the SNR of input pulse: higher input pulse SNR enhances the SNR improvement. The experimental platform was established on SILEX-Ⅰ laser facility. The ultra-short pulse from 3 TW compressor was attenuated and sent into the Sagnac loop. The nonlinear medium was a 5 cm long fused silica material and the attenuator transmittance was 55%. When the input pulse energy is 6.6 mJ, the pulse SNR is improved from 10-6 to 10-7 by third-order autocorrelator. The energy of the output pulse is 1.6 mJ, with efficiency about 24%. This method has no limit to the beam diameter, and thus can be used for short-pulse SNR enhancement in the large energy conditions.
2012,
24: 1741-1744.
Abstract:
To improve the far field focal spot in inertial confinement fusion, the paper analyzes the main factors affecting the focusing performance of continuous phase plates. The encircled energy fraction and the far-field root-mean-square spot size are analyzed. The results show that, the aperture error, alignment error and amplitude distortion error have little effect on the focusing ability of continuous phase plates. The wavefront distortion lowers the energy concentrated especially when the correlation length is equivalent to the minimum spatial period (about 10 mm) of continuous phase plates. Thus improving the correlation length of the wavefront distortion in the inertial confinement fusion system is an effective way to improve the energy concentration degree of the focal spot.
To improve the far field focal spot in inertial confinement fusion, the paper analyzes the main factors affecting the focusing performance of continuous phase plates. The encircled energy fraction and the far-field root-mean-square spot size are analyzed. The results show that, the aperture error, alignment error and amplitude distortion error have little effect on the focusing ability of continuous phase plates. The wavefront distortion lowers the energy concentrated especially when the correlation length is equivalent to the minimum spatial period (about 10 mm) of continuous phase plates. Thus improving the correlation length of the wavefront distortion in the inertial confinement fusion system is an effective way to improve the energy concentration degree of the focal spot.
2012,
24: 1745-1748.
Abstract:
Polyvinyl butyral (PVB) modified antireflective silica films were deposited on fused silica substrates by sol-gel process. The effect of PVB on the microstructure and laser induced damage threshold (LIDT) of the films was investigated. The results of nanoparticle analyzer, and scanning probe microscope show that PVB molecules surround and control the growth of silica particles, resulting in a stable sol with uniformly distributed silica particles. As a result, the film deposited from these PVB modified sols possesses uniform microstructures. The optimal PVB modified silica film has surface roughness of 3.25 nm. The adhesive-resistance test exhibits that the strength of PVB modified silica film increases due to the bond reaction between PVB molecules and silica particles. The addition of PVB to silica sol increases the LITD of films. By adding 1.0% PVB to silica sol, the LIDT of films increases from 30.0 J/cm2 to 40.1 J/cm2. The increase in LIDT is attributed to the increase in film strength and uniformity of film microstructures as an effect of PVB modification.
Polyvinyl butyral (PVB) modified antireflective silica films were deposited on fused silica substrates by sol-gel process. The effect of PVB on the microstructure and laser induced damage threshold (LIDT) of the films was investigated. The results of nanoparticle analyzer, and scanning probe microscope show that PVB molecules surround and control the growth of silica particles, resulting in a stable sol with uniformly distributed silica particles. As a result, the film deposited from these PVB modified sols possesses uniform microstructures. The optimal PVB modified silica film has surface roughness of 3.25 nm. The adhesive-resistance test exhibits that the strength of PVB modified silica film increases due to the bond reaction between PVB molecules and silica particles. The addition of PVB to silica sol increases the LITD of films. By adding 1.0% PVB to silica sol, the LIDT of films increases from 30.0 J/cm2 to 40.1 J/cm2. The increase in LIDT is attributed to the increase in film strength and uniformity of film microstructures as an effect of PVB modification.
2012,
24: 1749-1753.
Abstract:
The paper reports 13 and 12 photonic drop splitters (PDSs) for TE modes in a silicon photonic crystal based on self-collimation effect. The 13 PDS consists of four beam splitters and the 12 PDS consists of three beam splitters and one mirror. The theoretical transmission spectra at different drop ports in PDSs were analyzed with the multiple-beam interference theory. The PDSs with different splitting ratios can be designed by selecting beam splitters appropriately. For the 13 photonic drop splitter, we designed two splitting ratios of 1∶1∶1 and 1∶2∶3. For the 12 photonic drop splitter, we designed two splitting ratios of 1∶1 and 1∶2. Then the performances of the PDSs were investigated with the finite-difference time-domain (FDTD) simulation technique, whose results agree well with theoretical predictions. For the drop wavelength of 1550 nm, the dimensions of the PDSs are about 10 m10 m, and the free spectral range are about 36 nm, which almost covers the whole optical communication C-band window.
The paper reports 13 and 12 photonic drop splitters (PDSs) for TE modes in a silicon photonic crystal based on self-collimation effect. The 13 PDS consists of four beam splitters and the 12 PDS consists of three beam splitters and one mirror. The theoretical transmission spectra at different drop ports in PDSs were analyzed with the multiple-beam interference theory. The PDSs with different splitting ratios can be designed by selecting beam splitters appropriately. For the 13 photonic drop splitter, we designed two splitting ratios of 1∶1∶1 and 1∶2∶3. For the 12 photonic drop splitter, we designed two splitting ratios of 1∶1 and 1∶2. Then the performances of the PDSs were investigated with the finite-difference time-domain (FDTD) simulation technique, whose results agree well with theoretical predictions. For the drop wavelength of 1550 nm, the dimensions of the PDSs are about 10 m10 m, and the free spectral range are about 36 nm, which almost covers the whole optical communication C-band window.
2012,
24: 1754-1756.
Abstract:
The model of a radio-frequency waveguide was built. The interaction potential of Rb cold atoms with the magnetic field in the radio-frequency waveguide was analyzed. When an electric current is input into the coils of the waveguide, the potential depth at the center axis of the coils is about 1 mK. Such kind of waveguide can confine the cold atoms whose temperature is 100 K along the radial direction and guide them along the axial direction. The potential field in the waveguide changes as the input current changes. The force that the waveguide exerts on the atoms along the axis of the waveguide is 1.710－23 N, tenfold the gravity of a Rb atom.
The model of a radio-frequency waveguide was built. The interaction potential of Rb cold atoms with the magnetic field in the radio-frequency waveguide was analyzed. When an electric current is input into the coils of the waveguide, the potential depth at the center axis of the coils is about 1 mK. Such kind of waveguide can confine the cold atoms whose temperature is 100 K along the radial direction and guide them along the axial direction. The potential field in the waveguide changes as the input current changes. The force that the waveguide exerts on the atoms along the axis of the waveguide is 1.710－23 N, tenfold the gravity of a Rb atom.
2012,
24: 1757-1760.
Abstract:
Laser induced damage sites in fused silica were irradiated by a galvanometer scanned CO2 laser. Most damage sites are completely repaired (no ablation deposits, air bubbles and cracks) and the largest is 500 m in diameter. Compared with localized mitigation, scanning mitigation can repair larger-sized damage, and bring about smaller surface deformation and lower thermal stress. The damage testing at 355 nm shows that, 80% of the mitigated damage sites can withstand the laser power density up to the initial damage threshold of the substrate.
Laser induced damage sites in fused silica were irradiated by a galvanometer scanned CO2 laser. Most damage sites are completely repaired (no ablation deposits, air bubbles and cracks) and the largest is 500 m in diameter. Compared with localized mitigation, scanning mitigation can repair larger-sized damage, and bring about smaller surface deformation and lower thermal stress. The damage testing at 355 nm shows that, 80% of the mitigated damage sites can withstand the laser power density up to the initial damage threshold of the substrate.
2012,
24: 1761-1764.
Abstract:
An experimental study on ultrasonic cleaning of optics was carried out. Optimization of the cleaning process was performed through comparative experiments with different cleaning reagents and temperatures. The optimized cleaning process removes both organic pollutants and inorganic pollutants effectively. After optimized cleaning, the optics surface shows no additional damage, with the contact angle less than 6, and no pollutant particles larger than 1 m left. Ultrasonic cleaning attains a better cleaning effect than manual cleaning.
An experimental study on ultrasonic cleaning of optics was carried out. Optimization of the cleaning process was performed through comparative experiments with different cleaning reagents and temperatures. The optimized cleaning process removes both organic pollutants and inorganic pollutants effectively. After optimized cleaning, the optics surface shows no additional damage, with the contact angle less than 6, and no pollutant particles larger than 1 m left. Ultrasonic cleaning attains a better cleaning effect than manual cleaning.
