Spin-alignment noise in atomic vapor

A. A. Fomin,I. I. Ryzhov,M. Yu. Petrov,G. G. Kozlov,M. V. Balabas,V. S. Zapasskii,M. M. Glazov

doi:10.1103/physrevresearch.2.012008

A. A. Fomin, I. I. Ryzhov + Show 5 more

Open Access

https://doi.org/10.1103/physrevresearch.2.012008

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Abstract

In the conventional spin noise spectroscopy, the probe laser light monitors fluctuations of the spin orientation of a paramagnet revealed as fluctuations of its gyrotropy, i.e., circular birefringence. For spins larger than 1/2, there exists spin arrangement of a higher order---the spin alignment---which also exhibits spontaneous fluctuations. We show theoretically and experimentally that the alignment fluctuations manifest themselves as the noise of the linear birefringence. In a magnetic field, the spin-alignment fluctuations, in contrast to those of spin orientation, show up as the noise of the probe-beam ellipticity at the double Larmor frequency, with the most efficient geometry of its observation being the Faraday configuration with the light propagating along the magnetic field. We have detected the spin-alignment noise in a cesium-vapor cell probed at the wavelength of D2 line (852.35 nm). The magnetic-field and polarization dependence of the ellipticity noise are in full agreement with the developed theory.

Highlights

Properties of materials in physics are studied most frequently by measuring their response to external perturbations
The spin fluctuations contributing to the gyrotropy noise [Eq (1)] observed at the single Larmor frequency manifest themselves in the ellipticity in addition to the alignment noise [43]
We have shown that the spin noise spectra, usually detected via polarization noise of a probe laser beam, may reveal fluctuations of gyrotropy of the medium at Larmor frequency, and fluctuations of linear birefringence at the double Larmor frequency

Summary

Rapid Communications

In the conventional spin noise spectroscopy, the probe laser light monitors fluctuations of the spin orientation of a paramagnet revealed as fluctuations of its gyrotropy, i.e., circular birefringence. We show theoretically and experimentally that the alignment fluctuations manifest themselves as the noise of the linear birefringence. The spin-alignment fluctuations, in contrast to those of spin orientation, show up as the noise of the probe-beam ellipticity at the double Larmor frequency, with the most efficient geometry of its observation being the Faraday configuration with the light propagating along the magnetic field. We have detected the spin-alignment noise in a cesium-vapor cell probed at the wavelength of D2 line (852.35 nm). The magnetic-field and polarization dependencies of the ellipticity noise are in full agreement with the developed theory

Introduction

Published by the American Physical Society

Findings

Voigt geometry

Conclusion