Spatiotemporal optical vortices generation in the green and ultraviolet via frequency upconversion[Invited]  

作　　者：高雪晨 赵雨薇 王珏 卢扬 张家璇 范锦涛 胡明列 Xuechen Gao;Yuwei Zhao;Jue Wang;Yang Lu;Jiaxuan Zhang;Jintao Fan;Minglie Hu(Ultrafast Laser Laboratory,Key Laboratory of Opto-electronic Information Science and Technology of Ministry of Education,School of Precision Instruments and Opto-electronics Engineering,Tianjin University,Tianjin 300072,China;Science and Technology on Electro-Optical Information Security Control Laboratory,Tianjin 300308,China)

机构地区：[1]Ultrafast Laser Laboratory,Key Laboratory of Opto-electronic Information Science and Technology of Ministry of Education,School of Precision Instruments and Opto-electronics Engineering,Tianjin University,Tianjin 300072,China [2]Science and Technology on Electro-Optical Information Security Control Laboratory,Tianjin 300308,China

出　　处：《Chinese Optics Letters》2023年第8期12-16,共5页中国光学快报（英文版）

基　　金：supported by the National Natural Science Foundation of China(NSFC)(Nos.62105237,61827821,and 62227821).

摘　　要：As a newly discovered type of structured light,a spatiotemporal optical vortex(STOV),which is remarkable for its space–time spiral phase and transverse orbital angular momentum(OAM),has garnered substantial interest.Most previous studies have focused on the generation,characterization,and propagation of STOVs,but their nonlinear frequency conversion remains largely unexplored.Here,we experimentally demonstrate the generation of green and ultraviolet(UV)STOVs by frequency upconversion of a STOV carried near-infrared(NIR)pulse emitted by a high repetition rate Yb-doped fiber laser amplifier system.First,we verify that the topological charge of spatiotemporal OAM(ST-OAM)is doubled along with the optical frequency in the second-harmonic generation(SHG)process,which is visualized by the diffraction patterns of the STOVs in the fundamental and second-harmonic field.Second,the space–time characteristic of NIR STOV is successfully mapped to UV STOV by sum-frequency mixing STOV at 1037 nm and Gaussian beams in the green band.Furthermore,we observe the topological charges of the ST-OAM could be degraded owing to strong space–time coupling and complex spatiotemporal astigmatism of such beams.Our results not only deepen our understanding of nonlinear manipulation of STOAM spectra and the generation of STOVs at a new shorter wavelength,but also may promote new applications in both classical and quantum optics.

关 键 词：ultraviolet spatiotemporal optical vortex second-harmonic generation sum-frequency generation 

分 类 号：O43[机械工程—光学工程]