Zero-field spin noise spectrum of an alkali vapor with strong spin-exchange coupling

TL;DR

This paper investigates the zero-field optical spin noise spectra of hot 87Rb vapor with strong spin exchange coupling, revealing hyperfine correlations, polarization conditions, and power ratios, with a theoretical derivation approach.

Contribution

It provides the first detailed analysis of the hyperfine spin correlation components in zero-field spin noise spectra of alkali vapor with strong spin exchange coupling.

Findings

OSN spectrum has positive and negative hyperfine spin correlation components.

Existence of two polar frequencies with complete polarization of one HSC type.

Total OSN power is independent of spin exchange coupling strength.

Abstract

We study the zero-field optical spin noise spectra (OSN) for a thermal state hot 87Rb vapor with strong spin exchange coupling. Our main findings are: (1) The OSN spectrum consists of two components representing a positive and a negative hyperfine spin correlation (HSC), the relative power of which varies dramatically with the detuning frequency of the probe. (2) There exist two polar frequencies at which the OSN spectrum is completely polarized with one type of HSC. (3) At the limit of far detuning, the power ratio of the positive and negative HSC component of the OSN is 4:5. (4) The total power of the OSN is independent of the strength of SE coupling. (5) We give a simple way of deriving the OSN using the eigensolution of the density matrix equation.