Measuring spin-noise correlation function via time reversal

TL;DR

This paper introduces a simple, computationally efficient method for measuring the autocorrelation function of spin noise using time-reversal of digitized signals, applicable to spin noise and light-intensity noise studies.

Contribution

It presents a novel technique that replaces Fourier transform methods with a time-reversal averaging approach, reducing computational costs while preserving information.

Findings

Successfully measured spin noise in cesium vapors

Demonstrated the method's effectiveness with digital oscilloscopes

Discussed potential applications to light-intensity noise analysis

Abstract

We propose a simple method of measuring the autocorrelation function of a spin noise based on multiplication and averaging two digitized signal traces, with one of them being a time-reversed copy of the other. This procedure allows one to obtain, with lower computational expenses, all the information usually derived in the Fourier transform spin-noise spectroscopy, retaining all the merits of the latter. We successfully applied this method to the measurements of spin noise in cesium vapors by using a digital oscilloscope in the capacity of the analog-to-digital converter. Specific opportunities of this experimental approach as applied to a more general problem of studying the nature of light-intensity noise are discussed.