Single Plane Spatial Mode Sorter
Abstract
A mode sorter separates a set of M orthogonal spatial modes in a shared input channel into M different output channels. Here we present an analytic derivation and experimental validation of a single plane device for sorting spatial modes from a diverse variety of mode families, including Hermite-Gaussian (HG), Laguerre-Gaussian (LG), Bessel-Gaussian (BG), with almost no cross-talk. This sorting capability is required for a wide range of applications that employ classical or quantum light. We also show that applying this design in order to sort a set of Orbital Angular Momentum (OAM) modes with zero radial index reproduces the well-known Fork grating configuration. Furthermore, by taking the limit of M -> inf, we present an analytical expression for sorting all the modes of a given family. By operating this device in reverse, it can be used to generate arbitrary modes, by illuminating it with a Gaussian beam. The power transmission coefficient for this sorter goes as 1/M and we provide a mathematical proof that this is optimal for any typical arrangement of the detector positions. We further study the sorter sensitivity to wavelength and random phase noise.
Cite
@article{arxiv.2604.14119,
title = {Single Plane Spatial Mode Sorter},
author = {Khen Cohen and Yoav Yosif-Or and Yaron Oz and Ady Arie},
journal= {arXiv preprint arXiv:2604.14119},
year = {2026}
}
Comments
29 pages, 17 figures. Published in Opt. Express 34, 1837-1849 (2026)