Laguerre-Gaussian mode sorter

TL;DR

This paper introduces a novel device that can efficiently decompose light beams into a large number of orthogonal Laguerre-Gaussian modes, enabling high-dimensional spatial mode multiplexing for advanced optical applications.

Contribution

The paper presents the first device capable of decomposing both azimuthal and radial components of Laguerre-Gaussian modes simultaneously using a single spatial light modulator and mirror.

Findings

Decomposes over 210 spatial components.

Achieves highest dimensionality mode multiplexing.

Operates with a simple, compact setup.

Abstract

Light's spatial properties represent an infinite state space, making it attractive for applications requiring high dimensionality, such as quantum mechanics and classical telecommunications, but also inherently spatial applications such as imaging and sensing. However, there is no demultiplexing device in the spatial domain comparable to a grating or calcite for the wavelength and polarisation domains respectively. Specifically, a simple device capable of splitting a finite beam into a large number of discrete spatially separated spots each containing a single orthogonal spatial component. We demonstrate a device capable of decomposing a beam into a Cartesian grid of identical Gaussian spots each containing a single Laguerre-Gaussian component. This is the first device capable of decomposing the azimuthal and radial components simultaneously, and is based on a single spatial light modulator and mirror. We demonstrate over 210 spatial components, meaning it is also the highest dimensionality mode multiplexer of any kind.