Light deflection by light: Effect of incidence angle and inhomogeneity

TL;DR

This paper investigates how the incidence angle and inhomogeneity of a control beam influence light deflection in an atomic system, enabling dynamic control of angular divergence and lens-like focusing effects with minimal absorption.

Contribution

It introduces a method to control light deflection and focusing in an atomic vapor using inhomogeneous control fields with adjustable incidence angles and profiles.

Findings

Large angular divergence achievable with oblique control beam

Dynamic control of deflection via beam profile and angle

Medium acts as a lens with multiple focal points

Abstract

We study the angular deflection of the circular polarized components of a linearly polarized probe field in a weakly birefringent atomic system in tripod configuration. A spatially inhomogeneous control field incident obliquely onto an atomic vapor cell facilitates a large angular divergence between circular components. We show that the angular resolution can be dynamically controlled by optimally choosing the angle of incidence and the transverse profile of the control beam. For instance, by employing a Laguerre-Gaussian profile of the control field, one can impart a large angular divergence to the circular components close to the entry face of the atomic vapor cell. We further demonstrate how such a medium causes the focusing and refocusing of the probe field, thereby acting as a lens with multiple foci. The absorption in the medium remains negligible at resonance due to electromagnetically induced transparency (EIT).