Measurement of radiation coherence by means of interference visibility in the reflected light

TL;DR

This paper presents a novel method for measuring the spatial coherence of laser beams by analyzing interference visibility in reflected light using a rotated plane-parallel plate, enabling precise coherence width determination.

Contribution

The paper introduces a new technique for measuring beam spatial coherence through interference contrast analysis involving a rotated plate, validated on multimode lasers.

Findings

Effective measurement of spatial coherence width achieved

Method accurately determines beam coherence properties

Applicable to various multimode laser types

Abstract

Proposed, justified and tested measuring of beam spatial coherence, based on the detection of an interference visibility of the equal to intensity of beam replicas emerging under reflection from the rotated plane-parallel plate. The method consists in measuring the interference contrast at the simultaneous change of the longitudinal path difference and transverse shift of named replicas. Accurate measurement of the angle of rotated plate and the amplitude distribution of interferential minimaxes allows to determine the width of the beam spatial coherence. Spatial coherence of some types of multimode lasers has been measured by the method. Keywords: coherence measurements, interference in 2 move apart beam, rotable interferometer