Optoelectronic forces with quantum wells for cavity optomechanics in GaAs/AlAs semiconductor microcavities

摘要

Radiation pressure, electrostriction, and photothermal forces have beeninvestigated to evidence backaction, non-linearities and quantum phenomena incavity optomechanics. We show here that optoelectronic forces involving realcarrier excitation and deformation potential interaction are the strongestmechanism of light-to-sound transduction when exciting with pulsed lasers closeto the GaAs optical gap of semiconductor GaAs/AlAs distributed Bragg reflectoroptomechanical resonators. We demonstrate that the ultrafast spatialredistribution of the photoexcited carriers in microcavities with massive GaAsspacers leads to an enhanced coupling to the fundamental 20~GHz verticallypolarized mechanical breathing mode. The carrier diffusion can be limited byembedding GaAs quantum wells in the cavity spacer, a strategy used here toprove and engineer the role of optoelectronic forces in phonon generation withreal carriers. The optical forces associated to the different interveningmechanisms and their relevance for dynamical backaction in optomechanics isevaluated using finite-element methods. The results presented open the path tothe study of hitherto seldom investigated dynamical backaction inoptomechanical solid-state resonators in the presence of optoelectronic forces.