Acoustically driven storage of light in a quantum well

TL;DR

This paper demonstrates how surface acoustic waves can be used to trap and store light-related excitations in a quantum well, significantly extending their lifetime and enabling controlled release.

Contribution

It introduces a method to use piezoelectric fields from surface acoustic waves to dissociate and trap excitons in quantum wells, enabling long-term optical storage and controlled recombination.

Findings

Increased exciton radiative lifetime by orders of magnitude.

Controlled release of stored excitons via external screening.

Efficient trapping of electron-hole pairs in a moving potential.

Abstract

The strong piezoelectric fields accompanying a surface acoustic wave on a semiconductor quantum well structure are employed to dissociate optically generated excitons and efficiently trap the created electron hole pairs in the moving lateral potential superlattice of the sound wave. The resulting spatial separation of the photogenerated ambipolar charges leads to an increase of the radiative lifetime by orders of magnitude as compared to the unperturbed excitons. External and deliberate screening of the lateral piezoelectric fields triggers radiative recombination after very long storage times at a remote location on the sample.