[21a-E214-1~9] 4.6 Quantum Optics and Nonlinear Optics

▲ [21a-E214-5] Detection of orbital angular momentum-induced beam shifts by weak measurement

〇(M2)Wenjin Long¹, Wenguo Zhu¹, Jianhui Yu¹, Zhe Chen¹ (1.Jinan Univ.)

Keywords:weak measurement, orbital angular momentum, beam shifts

When a polarized light beam reflected upon a planar interface, extremely tiny but non-negligible beam shifts occur. Although the spin angle momentum induced beam shifts have been well measured by weak measurement technique, weak measurement for orbital angular momentum (OAM)-induced spatial shifts of vortex beams are still confusing.Here, by properly choosing the preselection and postselection states, the tiny OAM-induced shifts are amplified at an air-prism interface. The maximum shifts along directions both parallel and perpendicular to the incident plane are theoretically predicted and experimentally verified with optimal preselection and postselection states. Specially, the Imbert–Fedorov (IF) shifts can always be maximized for an arbitrary angle larger than 15°. Experimentally, the IF shift is up to 121.16μm at a specific parameter condition. The maximum shifts increase with the incident OAM gradually, thus can be used to identify the OAM precisely. We believe the proposed weak measurement scheme for vortex beam has potential applications in OAM identification and quantum information.