Carrier-mediated optomechanical forces in semiconductor nanomembranes with coupled quantum wells

Andreas Barg, Leonardo Midolo, Gabija Kiršanskė, Petru Tighineanu, Tommaso Pregnolato, Ataç İmamoǧlu, Peter Lodahl, Albert Schliesser, Søren Stobbe, and Eugene S. Polzik

Phys. Rev. B 98, 155316 – Published 22 October 2018

Abstract

In the majority of optomechanical experiments, the interaction between light and mechanical motion is mediated by radiation pressure, which arises from momentum transfer of reflecting photons. This is an inherently weak interaction, and optically generated carriers in semiconductors have been predicted to be the mediator of different and potentially much stronger forces. Here we demonstrate optomechanical forces induced by electron-hole pairs in coupled quantum wells embedded in a free-free nanomembrane. We identify contributions from the deformation potential and piezoelectric coupling and observe optically driven motion about three orders of magnitude larger than expected from radiation pressure. The amplitude and phase of the driven oscillations are controlled by an applied electric field, which tunes the carrier lifetime to match the mechanical period. Our work opens perspectives not only for enhancing the optomechanical interaction in a range of experiments but also for interfacing mechanical objects with complex macroscopic quantum objects, such as excitonic condensates.