贝塞尔光束在生物组织中的自重建特性研究  

Self-Reconstruction Characteristics of Bessel Beam in Biological Tissue

作　　者：谢家俊 唐诗瑶 陈永强 余文慧 李艳萍 沈炳林 屈军乐[1] 刘丽炜 Xie Jiajun;Tang Shiyao;Chen Yongqiang;Yu Wenhui;Li Yanping;Shen Binglin;Qu Junle;Liu Liwei(Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province,College of Physics and Optoelectronic Engineering,Shenzhen University,Shenzhen,Guangdong 518060,China)

机构地区：[1]深圳大学物理与光电工程学院,教育部/广东省光电子器件与系统重点实验室,广东深圳518060

出　　处：《中国激光》2022年第5期207-216,共10页Chinese Journal of Lasers

基　　金：国家自然科学基金(61961136005,61935012,61835009,62175163);深圳市科技计划国际合作项目(GJHZ20190822095420249);深圳市重点项目(JCYJ20200109105404067)。

摘　　要：贝塞尔光束在生物组织中的传输易受到样品散射的影响,从而削弱其自重建能力。本文将生物组织建模为折射率弱波动的湍流模型,在弱散射近似下,结合角谱理论及逐步传输算法对贝塞尔光束在生物组织中的传输及自重建过程进行了理论模拟。利用空间光调制器加载涡旋光束相位和轴棱锥相位的叠加相位全息图来调制高斯光束,以产生可调控的贝塞尔光束。结果表明:贝塞尔光束经过生物组织的相位扰动后,重建光束的无衍射距离大大缩短,光强远低于原光束,且生物组织越厚,重建光束的光强越低;轴棱锥的锥角决定了重建贝塞尔光束的中心亮斑或最内环形旁瓣的尺寸,但对重建贝塞尔光束无衍射距离的影响不大;同时,低阶贝塞尔光束展现出了更好的自重建能力。Objective Exploring the reconstruction characteristics of Bessel beams propagation in and through biological tissues has always been a complex problem. Many mature simulation methods such as Monte Carlo(MC), finite difference time domain(FDTD), and beam propagation method(BPM) are used for this exploration. MC is the gold standard for analyzing light propagation in the scattering medium. However, it treats light as particles, so it cannot accurately simulate light propagation with refractive-index variations in biological tissues. FDTD has been used to study the scattering effect of complex particles on Bessel beams with remarkable accuracy and robustness;still, its computational complexity makes the particle model only arranged in two-dimensional sequence space. BPM involves propagating an input beam over a small distance through homogeneous space and then correcting the refractive-index variations caused by the beam during the propagation step, which can be combined with a three-dimensional fractal turbulence model to simulate the propagation of Bessel beams in and through a scattering medium. Since biological tissues can act as a scattering medium, we used BPM and fractal turbulence model to study the reconstruction characteristics of Bessel beam propagation through biological tissues. This has reference value on constructing a new optical tweezer system in biomedical research.Methods A three-dimensional turbulence model was used to model biological tissue with refractive-index variations. By approximating weak scattering, Bessel beam generation and propagation in and through biological tissue were simulated using an algorithm that combined angular spectrum theory and the step-by-step propagation method. The angular spectrum theory uses the Fourier transform algorithm twice in the calculation process, significantly reducing computational complexity. When light propagates in biological tissue, the tissue is regarded as a stack of slices, through which the beam propagates uniformly and is disturbed with a phase

关 键 词：医用光学 贝塞尔光束 湍流模型 角谱理论 空间光调制器 

分 类 号：O436[机械工程—光学工程]