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

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 into 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 for not only enhancing the optomechanical interaction in a range of experiments, but also for interfacing mechanical objects with complex macroscopic quantum objects, such as excitonic condensates. arXiv:1708.05885v3 [cond-mat.mes-hall]

From cavity optomechanics to cavity-less exciton optomechanics: a review

“…The coefficient of thermal expansion for the III-V semiconductors in low temperatures is minimal, which is opposite to the low-dimensional semiconductor systems. Hence, the photothermal effect in exciton optomechanical systems based on semiconductor quantum wells in low temperatures can be neglected, 101 while for the low-dimensional exciton optomechanical system, the photothermal effect could not be neglected. 45 Andreas Barg et al investigated carrier-mediated optomechanical forces in semiconductor nanomembranes with coupled quantum wells.…”

“…45 Andreas Barg et al investigated carrier-mediated optomechanical forces in semiconductor nanomembranes with coupled quantum wells. 101 The free-free nanomembranes with embedded CQWs are shown in Fig. 6(a and b).…”

“…The existence of excitons gives rise to three kinds of optomechanical force in the exciton optomechanical system. 101 First, the opposite charges of electrons and holes result a large electric field, inducing piezoelectric shear stress. Second, the electron transition from the valence band to the conduction band increases the lattice constant, yielding a hydrostatic stress, which can be quantified by deformation-potential E dp : 102 E dp = − B d E g /d p ,where B is the bulk modulus, p is the pressure, and E g is the band gap.…”

Strain-induced exciton decomposition and anisotropic lifetime modulation in a GaAs micromechanical resonator

“…A. Barg et al have recently revealed how the exciton relaxation affects the optical drive efficiency of mechanical motion and experimentally showed how to optimize it with an external electric field [15]. However, its counter process, how mechanical motion affects the exciton relaxation process, has remained obscure.…”

Enhanced Cavity Optomechanics with Quantum-well Exciton Polaritons

“…In direct-bandgap semiconductors, photoelastic effects typically dominate optomechanical coupling [27] and are greatly enhanced near electronic resonances of the material [28]. Moreover, in micromechanical resonators hosting quantum wells (QWs), electronic transitions can be tailored to boost carrier-mediated mechanical effects [29]. In both cases, an increase of optical absorption affects the cavity finesse and favors photothermal effects, while mechanical dephasing can be activated through photogenerated carriers [30,31].…”