Faraday filtering of Raman light in an isotopically pure alkali metal vapor

TL;DR

This paper demonstrates a narrow-band atomic filter using the Faraday effect in isotopically pure rubidium vapor, effectively filtering Raman light separated by hyperfine splitting with significant suppression.

Contribution

It introduces a novel application of the Faraday effect in isotopically pure alkali vapor for narrow-band filtering of Raman light, supported by experimental and theoretical analysis.

Findings

Achieved -18 dB suppression at 70°C and 80 G magnetic field.

Validated filter performance with experimental spectra and theoretical models.

Demonstrated potential for precise Raman light filtering in atomic physics applications.

Abstract

We present an application of the Faraday effect to produce a narrow band atomic filter in an alkali metal vapor. In our experiment two Raman beams separated in frequency by the ground state hyperfine splitting in 87Rb are produced using an EOM and then filtered using the Faraday effect in an isotopically pure 85Rb thermal vapor. An experimental transmission spectra for the filter is presented along with a theoretical calculation. The performance of the filter is then demonstrated and characterized using a Fabry-Perot etalon. For a temperature of 70 degrees and a longitudinal magnetic field of 80 G a suppression to -18 dB is achieved, limited by the quality of the polarizers.