A compact single channel interferometer to study vortex beam propagation

TL;DR

This paper introduces a compact interferometer using a multifunctional diffractive optical element to study vortex beam propagation and scattering effects, providing a simple experimental setup for analyzing vortex beam deterioration.

Contribution

It presents a novel single channel interferometer design that enables detailed study of vortex beam propagation and scattering effects in a compact form.

Findings

Studied vortex beam scattering with different numbers of thin scatterers.

Provided insights into how vortex charge affects beam deterioration.

Demonstrated the interferometer's effectiveness for vortex beam analysis.

Abstract

We propose and demonstrate a single channel interferometer that can be used to study how vortex beams propagate. The interferometer consists of a multifunctional diffractive optical element (MDOE) synthesized by the spatial random multiplexing of a Fresnel zone plate and a spiral Fresnel zone plate with different focal lengths. The MDOE generates two co-propagating beams, such that only the beam carrying orbital angular momentum is modulated by an annular stack of thin scatterers located at the focal plane of the Fresnel zone plate, while the other beam passes through the centre of the annulus without any modulation. The interference pattern is recorded at the focal plane of the spiral Fresnel zone plate. The scattering of vortex beams through stacks consisting of different number of thin scatterers was studied using the proposed optical setup. Conflicting results have been reported earlier on whether higher or lower charge beams suffer more deterioration. The proposed interferometer provides a relatively simple and compact means of experimentally studying propagation of vortex beams through scattering medium.