基于全介质一维光子晶体的平面拓扑微分器(特邀)  

Planar Topological Differentiator Based on All-Dielectric One-Dimensional Photonic Crystal(Invited)

作　　者：刘洋 黄明川 陈钱坤 张斗国 Liu Yang;Huang Mingchun;Chen Qiankun;Zhang Douguo(Advanced Laser Technology Laboratory of Anhui Province,Department of Optics and Optical Engineering,School of Physical Sciences,University of Science and Technology of China,Hefei 230026,Anhui,China)

机构地区：[1]中国科学技术大学物理学院光学与光学工程系先进激光技术安徽省实验室,安徽合肥230026

出　　处：《光学学报》2024年第10期322-327,共6页Acta Optica Sinica

基　　金：国家自然科学基金(12134013,62127818);国家重点研发计划(2021YFA1400700);安徽省重点研究与开发计划项目(202104a05020010);中央高校基本科研业务费专项(WK2340000109)。

摘　　要：提出一种拓扑荷数为2的全介质一维光子晶体拓扑微分运算器件。通过优化设计光子晶体的透射率与入射角度的依赖关系以及出/入射光的偏振状态,该拓扑器件可以对入射光场进行各向同性的二维二阶光学微分运算,进而实现图像边缘增强成像和图像边缘信息高效提取。该平面型拓扑微分运算器件具有轻量化、高通量、高速度、易于大规模集成、低成本制备等特点,在光学计算、光学成像与传感等领域具有潜在的应用价值。Objective Edge detection technology based on optical analog differentiation is widely employed in fields such as microscopic imaging,data processing,and machine vision.In recent years,with the development of nanofabrication technology,various optical analog differentiators utilizing metasurfaces and metamaterials have been invented,which highly reduces the space required for optical imaging systems.We plan to propose a topological differentiator with a topological charge of 2 based on an all-dielectric one-dimensional photonic crystal(1DPC).By properly designing the bandgap structure of the 1DPC and the polarization state of input and output light fields,this topological device can perform isotropic two-dimensional second-order differential operations on the input optical field,leading to edge enhancement imaging and highly efficient edge information extraction.Methods The photonic chip is fabricated via PECVD(Oxford System 100,UK)of SiO_(2) and Si_(3)N_(4) layers on a standard microscope cover slip.All experiments are performed using a modified upright optical microscope(Ti2-U,Nikon,Japan),and the illumination beam with a central wavelength of 643 nm and a bandwidth of 2 nm is emitted from a supercontinuum fiber laser(SuperK EXU-6,NKT Photonics,Denmark).Left-handed circularly polarized input light incident on the objects of interest is placed on the photonic chip,and the right-handed circularly polarized component of output light passing through the photonic chip is filtered out with imaging conducted onto the detector.We introduce a spherical reference light to interfere with the output field to measure the winding number of topological charge.Results and Discussions According to the intensity profile in every direction of the back focal plane of the fabricated photonic chip,the optical transfer function of the chip satisfies the form required for second-order differentiation,which means this photonic chip can implement isotropic second-order differentiation.The interference result between reference light and o

关 键 词：物理光学 光学拓扑微分运算 边缘检测 全介质一维光子晶体 光学成像与传感 

分 类 号：O436[机械工程—光学工程]