改进型分形波带片的焦深特性研究

提出了一种具有增大焦深特性的改进型分形波带片(FZP).分析并推导了改进型分形波带片基于优化参数w的周期公式;计算了改进型分形波带片在菲涅耳近似下的衍射光场分布以及对应的横向光场分布特性因子,包括分辨率因子(G),施特雷尔比(S)以及旁瓣强度因子(M);同时分析了在不同的径向坐标r和r2下的改进型分形波带片的焦深特性,...     

Image edge-enhancement in optical microscopy with a phase mismatched spiral phase plate

We present a spiral phase filtering system with a large tolerance for edge enhancement of both phase and amplitude objects in optical microscopy.The method is based on a Fourier 4-f spatial filtering system.A phase mismatched spiral phase plate (SPP) fabricated by electron beam lithography is employed as the radial Hilbert transform for image edge enhancement.Compared with holography,SPP is simple,economical,reliable,and easy to integrate.     

Dynamic steering beams for efficient force measurement in optical manipulation

An efficient and inexpensive method that uses a glass plate mounted onto a motorized rotating stage as a beam-steering device for the generation of dynamic optical traps is reported.Force analysis reveals that there are drag and trapping forces imposed on the bead in the opposite directions,respectively,in a viscous medium.The trapped bead will be rotated following the beam’s motion before it reaches the critical escape velocity when the drag force is equal to the optical trapping force.The equilibrium condition facilitates the experimental measurement of the drag force with potential extensions to the determination of the viscosity of the medium or the refractive index of the bead.The proposed technique can easily be integrated into conventional optical microscopic systems with minimum modifications.     

基于深度学习的虚拟相衬成像方法

对于传统的显微镜来说,其相衬成像模式需要通过配备专用光阑、聚光镜或者在物镜上添加嵌件来实现,这就增加了相衬显微成像的难度和成本.鉴于此,本文提出了一种基于深度学习算法的虚拟相衬成像方法,只需要采用一台普通的光学明场显微镜获取细胞明场图像,然后使用深度学习方法,就可以将明场图像转换成相衬图像.将虚拟相衬图像与显微镜获取的标准相衬图像进行对比,对比结果证明了这种虚拟相衬成像方法的有效性,为低成本相衬显微成像提供了范例.     

基于入射角扫描方式的大量程绝对折射率传感方法

针对石墨烯基的折射率传感系统中存在的大量程和高测量灵敏度无法兼得且仅能实现相对折射率测量的问题,提出了一种基于全内反射式的大量程绝对折射率测量方法。该方法仅通过一维线性运动,实现了大范围角度的精确调控。利用光学4f系统,保证了采样点位置不随入射角的变化而变化。不同入射角下的扫描测量方法的折射率测量范围理论上可以达到1～1.5168,通过对不同质量分数的氯化钙溶液的折射率进行测量,从实验上获得7.203×10^-4 RIU的测量灵敏度。     

Optimization of computer-generated holograms for dynamic optical manipulation with uniform structured light spots

An optimized iterative technique combining the merits of conventional Gerchber-Saxton (G-S) and adaptive-additive (A-A) algorithms to design multilevel computer-generated holograms for the creation of a desirable structured intensity pattern for multiple optical manipulation is theoretically adopted. Optical trap arrays are demonstrated with the help of liquid crystal spatial light modulator and a microscopic optical tweezer system. Additionally, continuous locked-in transport and deflection of microparticles with the generated optical lattice is proven experimentally. The proposed method possesses apparent high efficiency, high uniformity, and dynamic and reconfigurable advantages.