Electromagnetically induced transparency with Laguerre-Gaussian modes in ultracold rubidium

TL;DR

This paper demonstrates electromagnetically induced transparency using Laguerre-Gaussian laser modes in ultracold rubidium gases, showing narrower resonance linewidths due to the spatial intensity distribution, with experimental results aligning well with theoretical models.

Contribution

It introduces the use of Laguerre-Gaussian modes in EIT experiments, revealing narrower linewidths compared to fundamental modes, and provides a theoretical model matching experimental data.

Findings

Laguerre-Gaussian modes produce narrower EIT resonances.

The spatial intensity profile causes linewidth narrowing.

Experimental results agree with the theoretical model.

Abstract

We demonstrate electromagnetically induced transparency with the control laser in a Laguerre-Gaussian mode. The transmission spectrum is studied in an ultracold gas for the D2 line in both $^{85}$Rb and $^{87}$Rb, where the decoherence due to diffusion of the atomic medium is negligible. We compare these results to a similar configuration, but with the control laser in the fundamental laser mode. We model the transmission of a probe laser under both configurations, and we find good agreement with the experiment. We conclude that the use of Laguerre-Gaussian modes in electromagnetically induced transparency results in narrower resonance linewidths as compared to uniform control laser intensity. The narrowing of the linewidth is caused by the spatial distribution of the Laguerre-Gaussian intensity profile.