All-optical steering of light via spatial Bloch oscillations in a gas of three-level atoms

TL;DR

This paper demonstrates how a standing-wave control field in a three-level atomic medium can induce spatial Bloch oscillations, enabling efficient, low-intensity all-optical beam steering without diffraction.

Contribution

It introduces a method to control light propagation using spatially engineered nonlinearities in atomic media, combining analytical and numerical analysis of Bloch oscillations of gap solitons.

Findings

Long-living Bloch oscillations of gap solitons achieved

Significant nonlinearity enhancement allows low-intensity self-focusing

Beam steering occurs without appreciable diffraction

Abstract

A standing-wave control field applied to a three-level atomic medium in a planar hollow-core photonic crystal waveguide creates periodic variations of linear and nonlinear refractive indexes of the medium. This property can be used for efficient steering of light. In this work we study, both analytically and numerically, the dynamics of probe optical beams in such structures. By properly designing the spatial dependence of the nonlinearity it is possible to induce long-living Bloch oscillations of spatial gap solitons, thus providing desirable change in direction of the beam propagation without inducing appreciable diffraction. Due to the significant enhancement of the nonlinearity, such self-focusing of the probe beam can be reached at extremely weak light intensities.