TheqQuantum acousto optic effect in Bose-Einstein condensate

TL;DR

This paper explores how a modulated Bose-Einstein condensate can act as a dynamic diffraction grating for light, revealing a transition from acousto-optic effects to atomic Bragg scattering with varying laser intensity.

Contribution

It demonstrates the acousto-optic effect in BECs and analyzes the transition to atomic Bragg scattering, including the influence of atomic interactions.

Findings

Observation of acousto-optic effect in BECs.

Transition from acousto-optic to atomic Bragg scattering regimes.

Reduction of acousto-optic effect with increased atomic interactions.

Abstract

We investigate the interaction between a single mode light field and an elongated cigar shaped Bose-Einstein condensate (BEC), subject to a temporal modulation of the trap frequency in the tight confinement direction. Under appropriate conditions, the longitudinal sound like waves (Faraday waves) in the direction of weak confinement acts as a dynamic diffraction grating for the incident light field analogous to the acousto-optic effect in classical optics. The change in the refractive index due to the periodic modulation of the BEC density is responsible for the acousto-optic effect. The dynamics is characterised by Bragg scattering of light fom the matter wave Faraday grating and simultaneous Bragg scattering of the condensate atoms from the optical grating formed due to the interference between the incident light and the diffracted light fields. Varying the intensity of the incident laser beam we observe the transition from the acousto-optic effect regime to the atomic Bragg scattering regime, where Rabi oscillations between two momentum levels of the atoms are observed. We show that the acousto-optic effect is reduced as the atomic interaction is increased.