Intensity correlation speckles as a technique for removing Doppler broadening

TL;DR

This paper introduces a novel intensity correlation method that completely removes Doppler broadening in electromagnetic emissions, enabling precise spectral analysis of distant sources and potential applications in cosmology.

Contribution

The paper presents a new technique using intensity correlation measurements to eliminate Doppler broadening, applicable to inaccessible sources and collision broadening.

Findings

Effective removal of Doppler broadening demonstrated

Applicable to cosmological redshift measurements

Method also removes collision-induced broadening

Abstract

A method involving intensity correlation measurements is described, which allows for the complete removal of Doppler broadening in the emission of electromagnetic radiation from far-away sources that are inaccessible to conventional Doppler-free measurements. The technique, relying on a correction to g(2) of order N-1, probes the separation between neighboring spectral lines and is also applicable to the elimination of broadening due to collisions (N is the number of emitting particles and g(2) is the second-order field correlation function). Possible applications include a determination of cosmological parameters from red shifts of gravitationally-lensed quasars.