基于马赫曾德干涉仪的两涡旋光束离轴干涉研究  

Study on the Off-axis Interference Between Two Vortex Beams Based on the Mach-ZehnderInterferometer

作　　者：王丹[1,2] 韩静雅 吕靖 李鑫 周海涛 WANG Dan;HAN Jingya;LU Jing;LI Xin;ZHOU Haitao(School of Physics and Electronic Engineering,Shanxi University,Taiyuan 030006,China;Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan 030006,China)

机构地区：[1]山西大学物理电子工程学院,山西太原030006 [2]山西大学极端光学协同创新中心,山西太原030006

出　　处：《山西大学学报（自然科学版）》2023年第6期1370-1377,共8页Journal of Shanxi University(Natural Science Edition)

基　　金：国家自然科学基金(11704235);山西省青年科技研究基金(201901D211166);山西省高等学校科技创新项目(2020L0038)。

摘　　要：能够准确识别和探测涡旋光束所承载的轨道角动量量子数,是开展以光场轨道角动量进行信息编码的高维量子通信的研究基础。目前的探测方式以干涉为主,其中涉及两束涡旋光之间的干涉法为“镜像干涉法”。该方法能有效识别轨道角动量的大小,但无法判断其和旋向相关的正负。文章基于全面、准确探测光子轨道角动量量子数的目的,将涡旋半波片获得的涡旋光束置于马赫曾德干涉仪的两臂,通过改变两臂的偏振态和涡旋半波片,获得轨道角动量量子数分别为l_(1)和l_(2)的两个涡旋光束,实验结合理论分析了二者之间的离轴干涉。干涉图样是中心有|l_(1)一l_(2)|个错位条纹的叉形光栅,光栅的开口方向反映了l_(1)—l_(2)的正负。因此,当参考光束的轨道角动量量子数明确已知时,由干涉图样可以准确识别待测光束的轨道角动量大小以及正负。该方法解决了对涡旋光束旋向的准确识别,有助于研究光子轨道角动量与物质的相互作用过程,为深入分析产生的新光场的轨道角动量模式提供了参考。Accurate identification and detection of the orbital angular momentum(OAM)quantum number,carried by vortex beam,is the basic technology for the study on OAM-coded high-dimensional quantum communication.The present detection method is interference,which covering the interference between two vortex beams named as"interference of the beam with its mirror image".This method can efficiently identify the magnitude of OAM,but it cannot determine its positive or negative related to the rotation direction of vortex.Intending to detect photon's OAM accurately and comprehensively,two vortex beams,generated by vortex halfwave plates with OAM quantum number l_(1)and l_(2),are put in two arms of a Mach-Zehnder interferometer.The off-axis interference between the two vortex beams is analyzed experimentally and theoretically.The obtained interference pattern is a fork-shaped grating with the number of|l_(1)-l_(2)|misaligned fringes,and the direction of fork reflects the positive(negative)of the difference l_(1)-l_(2).Therefore,when the OAM value for the reference beam is clearly known,the OAM value for the other vortex beam can be identified by referring to the interference fringes.This method solves the problem of accurately identifying the direction of the vortex beam,helps to study on the interaction process involving the OAM transferring between particles and light beams,and provides a reference for in-depth analysis of the OAM of the generated new light field.

关 键 词：涡旋光束 四波混频 轨道角动量 离轴干涉 涡旋波片 

分 类 号：O431.2[机械工程—光学工程]