Two-shot measurement of spatial coherence

TL;DR

This paper introduces a novel two-shot interferometric method to measure the two-dimensional cross-spectral density function of optical fields, enabling efficient characterization of spatial coherence properties.

Contribution

The authors present a new interferometric scheme using a Michelson interferometer with a converging lens to encode and measure the cross-spectral density function in just two shots.

Findings

Successfully measured various synthesized cross-spectral density functions

Achieved good agreement between measurements and theoretical predictions

Demonstrated the method's potential for analyzing spatial coherence in optical fields

Abstract

We propose and demonstrate an interferometric scheme for measuring the two-dimensional two-point cross-spectral density function in a two-shot manner. Our scheme comprises a Michelson interferometer with a converging lens in one of the arms of the interferometer, and the crosss-pectral density function of an input optical field gets encoded in the intensity distribution of the output interferograms. This scheme works for any cross-spectral density function that is real and that depends on the spatial coordinates only through their difference. Using this scheme, we report measurements of several lab-synthesized cross-spectral density functions with very good agreement with theory. Our measurement technique can be very important for applications that are based on utilizing the partial spatial coherence properties of optical fields.