Measuring the Complete Transverse Spatial Mode Spectrum of a Wave Field

TL;DR

This paper introduces a method to experimentally measure the complete transverse spatial mode spectrum of any monochromatic wave field, applicable in optics and atom optics, using a compact interferometric setup.

Contribution

The authors present a novel, efficient scheme for fully characterizing the spatial mode spectrum of wave fields, including a practical implementation for Hermite-Gaussian modes.

Findings

Effective measurement of the entire spatial mode spectrum

Implementation with a small number of refractive elements

Feasibility in both optical and atom optics contexts

Abstract

We put forward a method that allows the experimental determination of the entire spatial mode spectrum of any arbitrary monochromatic wave field in a plane normal to its propagation direction. For coherent optical fields, our spatial spectrum analyzer can be implemented with a small number of benchmark refractive elements embedded in a single Mach-Zehnder interferometer. We detail an efficient setup for measuring in the Hermite-Gaussian mode basis. Our scheme should also be feasible in the context of atom optics for analyzing the spatial profiles of macroscopic matter waves.