Vector analysis on the characteristics of continuous phase plate speckle under the strong focusing
-
摘要: 连续位相板(CPP)经过透镜聚焦后，在焦平面上形成一个散斑场，散斑场的统计性质决定了CPP的束匀滑特性。当使用大数值孔径透镜聚焦后，傍轴近似不再成立，因此分析CPP焦斑特性时标量衍射理论不再适用。采用Richard-Wolf矢量衍射理论对强聚焦条件下的CPP焦斑进行了计算，在此基础上分析了矢量焦斑场的统计特性，讨论了焦斑的轮廓。结果表明，由于非近轴的原因，矢量分析得到的焦斑尺寸略大，且通过矢量分析后能够得到z轴方向的光场分量。散斑场的振幅分布满足瑞利分布特性，强度分布满足负指数分布特性，且矢量合成方向的光强分布会略微偏离负指数分布特性。Abstract: Continuous phase plate (CPP) is a typical phase optical element. It will form a speckle field focused by a lens. The statistical characteristics of the speckle field affect the beam smoothing result. When a lens with large number aperture is used, scalar diffraction theory is unsuitable to analyze the distribution character of the focal spot because the paraxial approximation is no longer valid. In this paper, the Richar-Wolf vector diffraction theory is employed to calculate the focal spot of CPP under the strong focusing condition. Then both the profile of the focal spot and its statistical characteristics are discussed in detail. The results show that the spot size that calculated by the vector method is larger than which calculated by scalar method due to the non-paraxial effect. According to the feature of the vector method, the z-component of the light field can be obtained. The amplitude distribution of the speckle meets the Rayleigh distribution character, and its intensity distribution meets the negative exponential distribution character. Influenced by the z-component, the intensity distribution in the vectorial resultant direction will slightly deviate from the negative exponential distribution character .
-
Key words:
- continuous phase plate /
- speckle /
- strong focusing condition /
- vector diffraction
-
图 2 焦平面上矢量散斑光场的相对振幅
Figure 2. Electric field relative amplitude of vector speckles on the focus plate
图 3 散斑振幅的统计分布，接近瑞利分布
Figure 3. Statistical distribution of speckles amplitude, it’s Rayleigh distribution
图 4 CPP矢量散斑场的光强分布特性
Figure 4. Statistical distribution of vector speckles intensity of CPP
-
[1] Tikhonchuk V T. Physics of laser plasma interaction and particle transport in the context of inertial confinement fusion[J]. Nuclear Fusion, 2019, 59: 032001. doi: 10.1088/1741-4326/aab21a [2] Kato Y, Mima K, Miyanaga N, et al. Random phasing of high-power lasers for uniform target acceleration and plasma-instability suppression[J]. Physical Review Letters, 1984, 53(11): 1057-1060. doi: 10.1103/PhysRevLett.53.1057 [3] Tikhonchuk V T, Mounaix P H, Pesme D. Stimulated Brillouin scattering reflectivity in the case of a spatially smoothed laser beam interacting with an inhomogeneous plasma[J]. Physics of Plasmas, 1997, 4(7): 2658-2669. doi: 10.1063/1.872351 [4] 杨春林. 等离子体中散斑光场的传输特性[J]. 物理学报, 2018, 67:085201 doi: 10.7498/aps.67.20171795Yang Chunlin. Propagation characteristics of speckle field in plasma[J]. Acta Physica Sinica, 2018, 67: 085201 doi: 10.7498/aps.67.20171795 [5] Hüller S, Porzio A, Robiche J. Order statistics of high-intensity speckles in stimulated Brillouin scattering and plasma-induced laser beam smoothing[J]. New Journal of Physics, 2013, 15: 025003. doi: 10.1088/1367-2630/15/2/025003 [6] 杨春林. 位相叠加效应对连续位相板束匀滑特性的影响[J]. 红外与激光工程, 2020, 49:20190515 doi: 10.3788/IRLA20190515Yang Chunlin. Influence of phase additive effect on beam smoothing character of continuous phase plate[J]. Infrared and Laser Engineering, 2020, 49: 20190515 doi: 10.3788/IRLA20190515 [7] Goodman J W. 光学中的散斑现象: 理论与应用[M]. 曹其智, 陈家璧, 译. 北京: 科学出版社, 2009: 71Goodman J W. Speckle phenomena in optics: theory and applications[M]. Cao Qizhi, Chen Jiabi, trans. Beijing: Science Press, 2009: 71 [8] Wolf E. Electromagnetic diffraction in optical systems- I. An integral representation of the image field[J]. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 1959, 253(1274): 349-357. [9] Foley J T, Wolf E. Wave-front spacing in the focal region of high-numerical-aperture systems[J]. Optics Letters, 2005, 30(11): 1312-1314. doi: 10.1364/OL.30.001312 [10] Youngworth K S, Brown T G. Focusing of high numerical aperture cylindrical-vector beams[J]. Optics Express, 2000, 7(2): 77-87. doi: 10.1364/OE.7.000077 [11] Khonina S N, Golub I. Tighter focus for ultrashort pulse vector light beams: change of the relative contribution of different field components to the focal spot upon pulse shortening[J]. Journal of the Optical Society of America A, 2018, 35(6): 985-991. doi: 10.1364/JOSAA.35.000985 [12] Omatsu T, Litchinitser N M, Brasselet E, et al. Focus issue introduction: synergy of structured light and structured materials[J]. Optics Express, 2017, 25(14): 16681-16685. doi: 10.1364/OE.25.016681 [13] Tao S H, Yuan X C, Lin J, et al. Influence of geometric shape of optically trapped particles on the optical rotation induced by vortex beams[J]. Journal of Applied Physics, 2006, 100: 043105. doi: 10.1063/1.2260823 [14] Lin J, Rodríguez-Herrera O G, Kenny F, et al. Fast vectorial calculation of the volumetric focused field distribution by using a three-dimensional Fourier transform[J]. Optics Express, 2012, 20(2): 1060-1069. doi: 10.1364/OE.20.001060 [15] Huang Kun, Shi Peng, Cao G W, et al. Vector-vortex Bessel-Gauss beams and their tightly focusing properties[J]. Optics Letters, 2011, 36(6): 888-890. doi: 10.1364/OL.36.000888 -
下载:
点击查看大图
图(5)
计量
- 文章访问数: 532
- HTML全文浏览量: 252
- PDF下载量: 70
- 被引次数: 0
