Exploring the Interference Pattern and its Polarisation Structure of Shaped Light

Abstract

Orbital Angular Momentum (OAM) carried by light presenting a helical phase structure, with applications in optical trapping, imaging and quantum information, among various other domains. It has been established that the mathematical structure of OAM-carrying light is identical to that of maximally entangled bi-partite quantum system. Deeper insight into the attributes of structured light could be gained based on the phenomenon of interference, which has been the focus of investigations in relation to classical light as well as quantum particles [1]. The present study drew on the research that has been conducted with vector beams of identical topological charges along their left and right circular elements in order to undertake an analytical examination of the two-slit interference effects of the same and different OAM mode number. Results indicated that the topological charges (OAM mode number) of the initial beams could be determined through investigation of the interference patterns [2]. This was the case with Laguerre-Gaussian (LG) beams as well, with further verification of the anticipated patterns via experiments, which revealed good consistency. Additionally, experiment-based verification of polarisation ellipse plots of the interfered beams was also conducted. In this way, the polarisation distribution at all points on the interference pattern could be better understood. Moreover, the resultant interfered beams by using ring aperture showed Bessel-Gaussian amplitude profile. This implied that beams with Bessel-Gaussian intensity profile of 𝑙 (topological charge) were the outcomes of interference of Laguerre-Gaussian beams with the same l