Measuring the topological charge of optical vortices with a single plate

Measuring the topological charge(TC) of optical vortex beams by the edge-diffraction pattern of a single plate is proposed and demonstrated. The diffraction fringes can keep well discernible in a wide three-dimensional range in this method. The redundant fringes of the diffracted fork-shaped pattern in the near-field can determine the TC value, and the orientation of the fork tells the handedness of the vortex. The plate can be opaque or translucent, and the requirement of the translucent plate ...     

深刻蚀光栅及其应用

深刻蚀光栅是一个新兴的学科方向,具有亚波长和深刻蚀舣重特征的微纳光子学元件,表现出一系列特有的光学效应.石英玻璃是一种优良的光学材料,具有热稳定性能好、透过率高、成本低等优点.基于石英玻璃制作深刻蚀光栅,是实现不同功能光子学器件的一种新技术途径,具有十分重要的应用前景.     

一种改进型高精度激光三角位移传感器的结构设计研究

在对传统激光三角位移传感结构分析的基础上,提出了一种新的结构设计方案,推导出了相应的测距方程表达式.并对其进行了理论分析.表明此结构设计方案是可行的,并且在探测器尺寸一定的情况下利用此结构可以大大地提高测量范围.     

Grating imaging scanning lithography

We present a grating imaging scanning lithography system for the fabrication of large-sized gratings. In this technology, ±1-order diffractive beams are generated by a phase grating and selected by a spatial filter. Meanwhile, a 4f system enables the ±1-order diffractive beams to form a grating image with a clear jagged-edge boundary on the substrate. A high-precision two-dimensional （2D） mobile stage is used for complementary cyclical scanning, thereby effectively eliminating image stitching errors. The absence of such errors results in a seamless and uniform large-sized grating. Characterized by a simple structure, high energy use, and good stability, this lithography system is highly relevant to the high-speed and cost- effective production of large-sized gratings.     

Simplified mode analysis of guided mode resonance gratings with asymmetric coatings

A simplified modal method to explain the resonance phenomenon in guided mode resonance(GMR) gratings with asymmetric coatings is presented.The resonance observed is due to the interaction of two propagation modes inside the grating.The reflectivity spectra and electric field distributions calculated from the simplified modal method are compared using rigorous coupled-wave analysis(RCWA).The influences of high-order evanescent modes on the resonance peak are analyzed.A matrix Fabry-Perot(FP) resonance condition is developed to evaluate the resonance wavelength.An explanation for the resonance phenomenon observed based on the FP resonance phase condition is also proposed and demonstrated.The simplified method provides clear physical insights into GMR gratings that are useful for the analysis of a variety of other resonance gratings.     

基于蓝宝石材料的微结构增透性能研究

针对传统熔石英激光窗口在碱金属蒸气环境下易腐蚀的痛点问题,提出了在蓝宝石材料上制备增透微结构的方法,以实现耐高温、耐腐蚀的高透激光窗口。在理论仿真的基础上,采用干涉曝光与反应离子束刻蚀技术,在蓝宝石基底表面上制备了增透微结构,其对795 nm光的单面透过率达到99.23%。在此基础上,制备了双面增透微结构和一面增透微结构一面增透膜的蓝宝石窗口片,相较于蓝宝石基底,它们对795 nm光的透过率分别提升了12.13%和13.02%。高功率激光作用温升测试结果表明,当激光功率从35 W增加到99.6 W时,裸基板温度增加了5.9℃,但是双面增透样品的温升均为3.8℃,表明双面增透处理可以适当降低温升。同时,光束质量测试结果表明,当高功率激光作用下微结构窗口的温度控制在200℃以内时,双面增透样品的光束质量因子在横向上的变化小于0.05,在纵向上的变化小于0.06,表明该增透窗口对入射光光束质量的影响甚小。