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RSS2000 Vol. 12, No. 07
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2000,
12.
Abstract:
Both of the theoretical calculation and the experimental measurement were performed on the concentration of HO2- in the BHP (basic hydrogen peroxide) solution of the COIL. The variation rule of HO2- concentration versus the ratio of KOH & H2O2 was obtained. The experiments for the influence of HO2- concentration on the utilization of Cl2 and the laser output power were performed. The results were valuable for the optimization of the BHP makeup and the experimental parameters.
Both of the theoretical calculation and the experimental measurement were performed on the concentration of HO2- in the BHP (basic hydrogen peroxide) solution of the COIL. The variation rule of HO2- concentration versus the ratio of KOH & H2O2 was obtained. The experiments for the influence of HO2- concentration on the utilization of Cl2 and the laser output power were performed. The results were valuable for the optimization of the BHP makeup and the experimental parameters.
2000,
12.
Abstract:
A method of powerful laser energy measurement using integrated sphere was introduced. The principle, design request, and error analysis are given out．
A method of powerful laser energy measurement using integrated sphere was introduced. The principle, design request, and error analysis are given out．
2000,
12.
Abstract:
The stability and performance of the different types Jet plate for a small-scale Jet single oxygen generator (JSOG) was studied. A small-scale supersonic chemical oxygen-iodine lasers (COIL) system based on the Jet type single oxygen generator proved work well.
The stability and performance of the different types Jet plate for a small-scale Jet single oxygen generator (JSOG) was studied. A small-scale supersonic chemical oxygen-iodine lasers (COIL) system based on the Jet type single oxygen generator proved work well.
2000,
12.
Abstract:
As the material of an optical window plane being transmitted through by high-power laser, some part of the laser energy would be absorbed and it may get thermal-deformation and become into thermal-lens. Here we begin from an analysis solution, which has got by us, of the distribution of heat-field in a circular material plane and consisted with the solid mechanics, then the expression of the thermal-focus length has been obtained. The effects different between materials of Al2O3 single crystal and fused silicon has been calculated and compared in 1.315 μm wavelength. Al2O3 single crystal plane is one of the optical material provided with high transparence and high threshold strength in wavelength 1.315 μm. But the ordinary and extraordinary light would be separated in the crystal. This e
As the material of an optical window plane being transmitted through by high-power laser, some part of the laser energy would be absorbed and it may get thermal-deformation and become into thermal-lens. Here we begin from an analysis solution, which has got by us, of the distribution of heat-field in a circular material plane and consisted with the solid mechanics, then the expression of the thermal-focus length has been obtained. The effects different between materials of Al2O3 single crystal and fused silicon has been calculated and compared in 1.315 μm wavelength. Al2O3 single crystal plane is one of the optical material provided with high transparence and high threshold strength in wavelength 1.315 μm. But the ordinary and extraordinary light would be separated in the crystal. This e
2000,
12.
Abstract:
This paper studies the thermal lensing effect of optical element under laser heating at non-thermal equilibrium state. The experiment of time sequence observation of laser orientation angel for transmitting laser beam through an optical element under heating of powerful laser has been carried out. It has been found that before thermal equilibrium to become established in the element, its thermal lensing effect presents a kind of behavior of fluctuation. The authors have also provided a preliminary explanation for this phenomenon and pointed out its practical sense.
This paper studies the thermal lensing effect of optical element under laser heating at non-thermal equilibrium state. The experiment of time sequence observation of laser orientation angel for transmitting laser beam through an optical element under heating of powerful laser has been carried out. It has been found that before thermal equilibrium to become established in the element, its thermal lensing effect presents a kind of behavior of fluctuation. The authors have also provided a preliminary explanation for this phenomenon and pointed out its practical sense.
2000,
12.
Abstract:
Using the approximation of thin layer gain and conditions of inhomogeneous broaden, COIL unstable Cavity experiment were simulated by C-7 code. Computational results indicate that those of numerical simulation agree with the experiment results.
Using the approximation of thin layer gain and conditions of inhomogeneous broaden, COIL unstable Cavity experiment were simulated by C-7 code. Computational results indicate that those of numerical simulation agree with the experiment results.
2000,
12.
Abstract:
The principle and the main steps of the program based on coupledwave theory for calculating the diffraction property of gratings are introduced. The diffraction properties of TE and TM polarization for a beamsampling grating are numerically analyzed with this program.
The principle and the main steps of the program based on coupledwave theory for calculating the diffraction property of gratings are introduced. The diffraction properties of TE and TM polarization for a beamsampling grating are numerically analyzed with this program.
2000,
12.
Abstract:
Using the heat exchanging system composed of an acentric pump and heat exchanger, the time is shortened in BHP solution premixing and the heat exchanging efficiency of O2(1?) generator is improved. In the meanwhile, the generator has the property of dynamic transmission, and the output power is increased.
Using the heat exchanging system composed of an acentric pump and heat exchanger, the time is shortened in BHP solution premixing and the heat exchanging efficiency of O2(1?) generator is improved. In the meanwhile, the generator has the property of dynamic transmission, and the output power is increased.
2000,
12.
Abstract:
A series of laser output experiments were done on COIL, in which a pipearray jettype O2(1Δ) generator was employed. The experimental investigation emphasized on the performance, parameters and relative techniques of the generator. A chemical efficiency of 22.2% was obtained in the experiments．
A series of laser output experiments were done on COIL, in which a pipearray jettype O2(1Δ) generator was employed. The experimental investigation emphasized on the performance, parameters and relative techniques of the generator. A chemical efficiency of 22.2% was obtained in the experiments．
2000,
12.
Abstract:
By finiteelement method, the temperature field of SiO2 and Al2O3 have been studied, under the condition whether laser power density in dimension is equal and the window is cooled or not . From the calculation result, a conclusion can be drawn that whether the mirror is SiO2 or Al2O3 the window is cooling and rotating by the vortex tube is help for laser output．
By finiteelement method, the temperature field of SiO2 and Al2O3 have been studied, under the condition whether laser power density in dimension is equal and the window is cooled or not . From the calculation result, a conclusion can be drawn that whether the mirror is SiO2 or Al2O3 the window is cooling and rotating by the vortex tube is help for laser output．
2000,
12.
Abstract:
A new complex structure of mirror cooled by phase change is presented in this paper. The advantage of silicon mirror and copper mirror was used and the defect of them was avoided simultaneously. Thermal distortion of mirror can be decreased effectively. Experiment of Comparing Mo-Cu complex mirror with Si mirror was done. It is shown that thermal distortion of Mo-Cu complex mirror is about half as much as thermal distortion of silicon mirror．
A new complex structure of mirror cooled by phase change is presented in this paper. The advantage of silicon mirror and copper mirror was used and the defect of them was avoided simultaneously. Thermal distortion of mirror can be decreased effectively. Experiment of Comparing Mo-Cu complex mirror with Si mirror was done. It is shown that thermal distortion of Mo-Cu complex mirror is about half as much as thermal distortion of silicon mirror．
2000,
12.
Abstract:
There exist phase sudden change of the output laser wave surface between the annular area and the shelter central area in normal type unstable resonators. It would lead to the laser energy divergence seriously in the far field. Specially, the intensity of central disk of far field will then be reduced. We have given it's theory analysis in detailed in ref［１］. This paper we emphasize in experimental research of this type of laser resonators with homogenized phase. On the situation of cavity rence transparent radio in laser light from central area have been chosen. All of the experiments are working in a copper vapor laser system with a large aperture. Good agreement results with the theory analysis have obtained. Specially, reducing the farfield divergence angles in 34% as the transpar
There exist phase sudden change of the output laser wave surface between the annular area and the shelter central area in normal type unstable resonators. It would lead to the laser energy divergence seriously in the far field. Specially, the intensity of central disk of far field will then be reduced. We have given it's theory analysis in detailed in ref［１］. This paper we emphasize in experimental research of this type of laser resonators with homogenized phase. On the situation of cavity rence transparent radio in laser light from central area have been chosen. All of the experiments are working in a copper vapor laser system with a large aperture. Good agreement results with the theory analysis have obtained. Specially, reducing the farfield divergence angles in 34% as the transpar
2000,
12.
Abstract:
After optimizing the design of the thin films and improving the control methods of film thickness , we have coated the anti-reflection film based on the quartz by Ta2O5/SiO2,and get the good result:R1315<0.05%．
After optimizing the design of the thin films and improving the control methods of film thickness , we have coated the anti-reflection film based on the quartz by Ta2O5/SiO2,and get the good result:R1315<0.05%．
2000,
12.
Abstract:
The circumstance of primary flow mixed with the secondary flow are numerically simulated by varying the flow rate of He in the secondary flow with the same primary flow and the same flow rate of I2 in the secondary flow. The conclusion is obtained by comparing and analyzing these results, that the penetration depth of the transverse secondary flow in the primary flow extends and the state of primary flow mixed with the secondary flow becomes better with the flow rate of He in the secondary flow increased, until the primary flow and the secondary flow are welldistributed.
The circumstance of primary flow mixed with the secondary flow are numerically simulated by varying the flow rate of He in the secondary flow with the same primary flow and the same flow rate of I2 in the secondary flow. The conclusion is obtained by comparing and analyzing these results, that the penetration depth of the transverse secondary flow in the primary flow extends and the state of primary flow mixed with the secondary flow becomes better with the flow rate of He in the secondary flow increased, until the primary flow and the secondary flow are welldistributed.
2000,
12.
Abstract:
In order to make 45° high reflection mirror at 1315nm and offer some experimental data, we discuss the following aspectsoptimization of the design of the thin films, the control of the depth of the thin films, the improvement of the surface of the thin films and the balance of the stress in the thin films. we give some methods to improve the characteristic of the thin films, and finally get the satisfied results about the making high reflection mirror:R>99.85%．
In order to make 45° high reflection mirror at 1315nm and offer some experimental data, we discuss the following aspectsoptimization of the design of the thin films, the control of the depth of the thin films, the improvement of the surface of the thin films and the balance of the stress in the thin films. we give some methods to improve the characteristic of the thin films, and finally get the satisfied results about the making high reflection mirror:R>99.85%．
2000,
12.
Abstract:
Using surface thermal lensing method to measure weak absorption of the thin films coated on the Si plates at 1315nm, we have concluded the reason that induced absorption, and can give a measuring guarantee to reduce their absorption and loss in the process of coating thin films．
Using surface thermal lensing method to measure weak absorption of the thin films coated on the Si plates at 1315nm, we have concluded the reason that induced absorption, and can give a measuring guarantee to reduce their absorption and loss in the process of coating thin films．
2000,
12.
Abstract:
The dissociation of chlorine molecule has been detected by dissociating the mixture of Cl2 and Ar in the microwave generator. The chlorine atom concentration increased when the pressure of the reactor cell various from 200Pa to 253Pa, we get the Cl2 dissociation over 8% at 256Pa. However, the value dropped rapidly with further increasing the pressure of the cell. It is probably due to the fast recombination rate of the Cl atom at high pressure.
The dissociation of chlorine molecule has been detected by dissociating the mixture of Cl2 and Ar in the microwave generator. The chlorine atom concentration increased when the pressure of the reactor cell various from 200Pa to 253Pa, we get the Cl2 dissociation over 8% at 256Pa. However, the value dropped rapidly with further increasing the pressure of the cell. It is probably due to the fast recombination rate of the Cl atom at high pressure.
2000,
12.
Abstract:
Laser modes in thermal deformation resonators are calculated and analyzed by means of perturbation methods. The coupling among laser modes and the relations between equivalent beam spread angle and the surface deformation of the mirrors are obtained. The theoretical results show that the bigger the thermal deformation at the center of a mirror and the stronger the coupling among laser modes, the more seriously the modes in a laser resonator are distorted. When the thermal deformation value at the center of a mirror is 0.5λ, the central laser intensity of TEM0 is reduced to 50% , and the equivalent beam spread angle is increased to 2 times of the ideal mirror．
Laser modes in thermal deformation resonators are calculated and analyzed by means of perturbation methods. The coupling among laser modes and the relations between equivalent beam spread angle and the surface deformation of the mirrors are obtained. The theoretical results show that the bigger the thermal deformation at the center of a mirror and the stronger the coupling among laser modes, the more seriously the modes in a laser resonator are distorted. When the thermal deformation value at the center of a mirror is 0.5λ, the central laser intensity of TEM0 is reduced to 50% , and the equivalent beam spread angle is increased to 2 times of the ideal mirror．
2000,
12.
Abstract:
The circumstance of primary flow mixed with the secondary flow, and the distribution of the physical variables describing the flowfield are studied by varying the flowrate with the same composition of primary and secondary flow. The conclusion is obtained by comparing and analyzing these results, that the state of primary flow mixed with the secondary flow becoming worse, but not very worse, and the distribution of Mach number and mass density being almost not changed with the flowrate increased to 3 times.
The circumstance of primary flow mixed with the secondary flow, and the distribution of the physical variables describing the flowfield are studied by varying the flowrate with the same composition of primary and secondary flow. The conclusion is obtained by comparing and analyzing these results, that the state of primary flow mixed with the secondary flow becoming worse, but not very worse, and the distribution of Mach number and mass density being almost not changed with the flowrate increased to 3 times.
2000,
12.
Abstract:
The mixed flowfield performance, small signal gain distribution, and output power are numerically simulated by changing the position of the iodine injector with constant primary and secondary flowrate. This study shows that the mixed flowfield results worse, the magnitude of small signal gain becomes smaller, the output power gets lower, and the decay of laser intensity vs x goes slower while the position of the iodine injector moves forward alone the flow direction.
The mixed flowfield performance, small signal gain distribution, and output power are numerically simulated by changing the position of the iodine injector with constant primary and secondary flowrate. This study shows that the mixed flowfield results worse, the magnitude of small signal gain becomes smaller, the output power gets lower, and the decay of laser intensity vs x goes slower while the position of the iodine injector moves forward alone the flow direction.
2000,
12.
Abstract:
Laserinduced damage thresholds (LIDT) of several kinds of optical dielectric coatings were measured using some lasers with different output characteristics. Typical damage process was discovered through microcosmic analysis of coatings. In particular, the influences of laser output characteristics on laserinduced damage statuses in coatings were investigated. It's given that a pulsed laser is easier to damage an objective than a continuouswave laser in condition of the same laser energy. However, CW laser can easily cause ablation damage in objectives by accumulation of energy．
Laserinduced damage thresholds (LIDT) of several kinds of optical dielectric coatings were measured using some lasers with different output characteristics. Typical damage process was discovered through microcosmic analysis of coatings. In particular, the influences of laser output characteristics on laserinduced damage statuses in coatings were investigated. It's given that a pulsed laser is easier to damage an objective than a continuouswave laser in condition of the same laser energy. However, CW laser can easily cause ablation damage in objectives by accumulation of energy．
2000,
12.
Abstract:
In Chemical-Mechanical polishing experiments we produced optical quality super smooth surfaces on singlecrystal silicon, but cannot insure the surface figure. In order to avoid the alveoli and achieve a good optical surface, a continuously adding slurry method with digging four welldistributed holes was used and advanced in this article. The best results were obtained as 0.268λ peak to peak surface (its diameter 152.4mm) and rms 0.065λ using this method.
In Chemical-Mechanical polishing experiments we produced optical quality super smooth surfaces on singlecrystal silicon, but cannot insure the surface figure. In order to avoid the alveoli and achieve a good optical surface, a continuously adding slurry method with digging four welldistributed holes was used and advanced in this article. The best results were obtained as 0.268λ peak to peak surface (its diameter 152.4mm) and rms 0.065λ using this method.
2000,
12.
Abstract:
A calibrated piston source of light, which simulates a cylindrical-volume luminosity source, has been introduced to measure the absolute concentration of illuminant particles. It is proved that this Piston Source Method is one of the simplest and most convenient ways to measure the absolute concentration of illuminant particles, especially in real time measurements of O2(a1? ) in a singlet oxygen generator. The relative error of O2(a1? ) concentration is less than 20%.
A calibrated piston source of light, which simulates a cylindrical-volume luminosity source, has been introduced to measure the absolute concentration of illuminant particles. It is proved that this Piston Source Method is one of the simplest and most convenient ways to measure the absolute concentration of illuminant particles, especially in real time measurements of O2(a1? ) in a singlet oxygen generator. The relative error of O2(a1? ) concentration is less than 20%.
2000,
12.
Abstract:
Because of the complicated kinetic reasons, the gain distribution in laser medium is usually inhomogeneous for Chemical Oxygen Iodine Laser, it will cause the laser output power will not increased with the increasing of the laser output aperture, and it is also by the same reason, the laser output power will be varied with the position of optical axis, even if the laser output aperture keep constant. So, when the laser parameters is constant, the laser output power has the dependence on laser output aperture and position of optical axis, and this dependence is reported in this paper.
Because of the complicated kinetic reasons, the gain distribution in laser medium is usually inhomogeneous for Chemical Oxygen Iodine Laser, it will cause the laser output power will not increased with the increasing of the laser output aperture, and it is also by the same reason, the laser output power will be varied with the position of optical axis, even if the laser output aperture keep constant. So, when the laser parameters is constant, the laser output power has the dependence on laser output aperture and position of optical axis, and this dependence is reported in this paper.
2000,
12.
Abstract:
The experimental rule for the variation of laser power versus the flowrate of iodine was obtained on a COIL device using a jettype singlet oxygen generator with pipearray, in which the flowrate of Cl2 was 250mmol/s. Theoretical analysis was given for the phenomenon. The results can help us to optimize the flowrate of iodine.
The experimental rule for the variation of laser power versus the flowrate of iodine was obtained on a COIL device using a jettype singlet oxygen generator with pipearray, in which the flowrate of Cl2 was 250mmol/s. Theoretical analysis was given for the phenomenon. The results can help us to optimize the flowrate of iodine.
2000,
12.
Abstract:
Based on the computational spectra simulation, the molecular iodine fluorescence in the cavity of chemical oxygeniodine laser was studied and found the numerical fitting spectra almost agreeable with the experimental results when the vibrational distribution of I2(B,V') at the center of Ｖ'=16 goes Gauss profile.
Based on the computational spectra simulation, the molecular iodine fluorescence in the cavity of chemical oxygeniodine laser was studied and found the numerical fitting spectra almost agreeable with the experimental results when the vibrational distribution of I2(B,V') at the center of Ｖ'=16 goes Gauss profile.
2000,
12.
Abstract:
The breakup lengths of jets for glycerine and water solution emerged from the nozzles with the various passage/diameter ratio, and different manufacture methods, were experimentally investigated. The behavior of a jet depends dramatically on the flow state, laminar or turbulent, in the nozzle. The turbulence induced by the defects of nozzle, such as the burr at the inlet and outlet, and the roughness of the wall, is the main cause to decrease the length of intact jet. These results may be helpful to design and manufacture an appropriate nozzle of the jet O2(1Δ) generators for COIL.
The breakup lengths of jets for glycerine and water solution emerged from the nozzles with the various passage/diameter ratio, and different manufacture methods, were experimentally investigated. The behavior of a jet depends dramatically on the flow state, laminar or turbulent, in the nozzle. The turbulence induced by the defects of nozzle, such as the burr at the inlet and outlet, and the roughness of the wall, is the main cause to decrease the length of intact jet. These results may be helpful to design and manufacture an appropriate nozzle of the jet O2(1Δ) generators for COIL.
