Mirror-assisted backscattering interferometry to measure the first-order correlation function of the light emitted by quantum scatterers

TL;DR

This paper introduces a mirror-assisted backscattering interferometry technique to directly measure the first-order correlation function of light from quantum scatterers, enabling analysis of their spectral properties.

Contribution

The authors develop a simplified interferometric method with a half waveplate to measure $g^{(1)} ( au)$ uniformly across atoms, improving spectral analysis of quantum emitters.

Findings

Method accurately measures $g^{(1)} ( au)$ for quantum scatterers.

Enables direct determination of the saturated emission spectrum.

Provides an analogy with a double Mach-Zehnder interferometer.

Abstract

We present a new method to obtain the first-order temporal correlation function, $g^{(1)} (\tau)$, of the light scattered by an assembly of point-like quantum scatterers, or equivalently its spectral power distribution. This new method is based on the mirror-assisted backscattering interferometric setup. The contrast of its angular fringes was already linked in the past to the convolution of $g^{(1)} (\tau)$ for different Rabi frequencies taking into account the incoming spatial intensity profile of the probe beam, but we show here that by simply adding a half waveplate to the interferometer in a specific configuration, the fringe contrast becomes $g^{(1)} (\tau)$ of the light scattered by atoms, which are now all subjected to the same laser intensity. This new method has direct application to obtain the saturated spectrum of quantum systems. We discuss some non-trivial aspects of this interferometric setup, and propose an analogy with a double Mach-Zehnder interferometer.