Exploiting scattering for single-shot measurement of the orbital angular momentum spectrum of light fields

Abstract

Coherent measurement of orbital angular momentum (OAM) spectrum of light fields plays a key role in many important applications, such as OAM-based multiplexing in optical communications. The existing methods for measuring the OAM spectrum by spatially separating OAM components or interferometric technique suffer from poor efficiency and interferometric stability requirements. Here, we propose a novel technique to measure the OAM spectrum of light fields in a single shot manner by exploiting a scattering optical element. Our technique enables to directly extract the OAM spectrum from a recorded single-shot speckle pattern using algorithms based on the speckle-correlation scattering matrix and spatial mode decomposition method. As a proof of concept, we built a robust measurement system based on a fast digital micromirror device to demonstrate the feasibility of the proposed technique.