Lensing effect of electromagnetically induced transparency involving a Rydberg state

TL;DR

This paper investigates how electromagnetically induced transparency involving Rydberg states can create a gradient-index lensing effect on a probe beam, resulting in focusing or defocusing depending on detuning, with experimental results matching simulations.

Contribution

It demonstrates the lensing effect in EIT involving Rydberg states and provides experimental and numerical analysis of the phenomenon.

Findings

Red-detuned probe light is strongly focused with enhanced intensity.

Blue-detuned probe light is de-focused with reduced intensity.

Experimental results align well with Maxwell-Bloch simulations.

Abstract

We study the lensing effect experienced by a weak probe field under conditions of electromagnetically induced transparency (EIT) involving a Rydberg state. A Gaussian coupling beam tightly focused on a laser-cooled atomic cloud produces an inhomogeneity in the coupling Rabi frequency along the transverse direction and makes the EIT area acting like a gradient-index medium. We image the probe beam at the position where it exits the atomic cloud, and observe that a red-detuned probe light is strongly focused with a greatly enhanced intensity whereas a blue-detuned one is de-focused with a reduced intensity. Our experimental results agree very well with the numerical solutions of Maxwell-Bloch equations.