Polarization spectroscopy of an excited state transition

TL;DR

This paper demonstrates polarization spectroscopy of an excited state transition in cesium vapor at room temperature, revealing sub-natural linewidth features useful for laser stabilization.

Contribution

It introduces a novel polarization spectroscopy technique for excited state transitions, highlighting its simplicity and effectiveness for laser frequency stabilization.

Findings

Observation of anisotropy induced by circularly polarized pump

Detection of sub-natural linewidth features when D2 transition is saturated

Theoretical modeling confirms Doppler averaging enhances the signal

Abstract

We demonstrate polarization spectroscopy of an excited state transition in room temperature cesium vapor. An anisotropy induced by a circularly polarized pump beam on the D2 transition is observed using a weak probe on the 6P3/2 to 7S1/2 transition. When the D2 transition is saturated, a sub-natural linewidth feature is observed which theoretical modeling shows is enhanced by Doppler averaging. Polarization spectroscopy provides a simple modulation-free signal suitable for laser frequency stabilization to excited state transitions.