Generation of longitudinally polarized multi-segment optical needles by tightly focusing RPBG beam  

作　　者：SHI Changkun SONG Yiding DONG Bing ZHOU Zhanqi ZHANG Zengqi XU Zongwei 

机构地区：[1]State Key Laboratory of Precision Measuring Technology&Instruments,Tianjin University,Tianjin 300072,China [2]School of Optical-Electrical and Computer Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China

出　　处：《Optoelectronics Letters》2023年第7期399-404,共6页光电子快报（英文版）

基　　金：supported by the ‘111’ Project by the State Administration of Foreign Experts Affairs;the 2020 Mobility Programme of the Sino-German Center for Research Promotion (M-0396);the Ministry of Education of China (No.B07014);the National Natural Science Foundation of China (Nos.11974258 and 11604236);the Key Research and Development (R&D) Projects of Shanxi Province (No.201903D121127)。

摘　　要：In this paper,an effective method to garner sub-wavelength longitudinally polarized multi-segment optical needle sequence by using a specially designed hybrid filter(HF) in a high numerical aperture(NA) objective focusing system is proposed.The HF is coupled by a binary phase transmission function and a multi-segment modulation function,and the binary phase filter is designed by the particle swarm optimization(PSO) algorithm and acts on the radially polarized Bessel Gaussian(RPBG) beam to obtain a longitudinally polarized optical needle with long depth of focus(DOF,6λ) and a sub-wavelength transverse spot size(0.430λ).The optical needle is with high uniformity of 98% and high beam quality of 96%,and the negligible sidelobe is 15%.On this basis,the multi-segment optical needle sequence with tunable spacing or number can be realized by the multi-segment modulation function.It is found that the HF makes the generation of multi-segment optical needle sequence more flexible and reliable.This research has broad application prospects in material processing,particle acceleration,particle capture and other fields.

关 键 词：FUNCTION POLARIZED BEAM 

分 类 号：O439[机械工程—光学工程]