Lecture: Micropillars, polaritons and optomechanics

15.02.2017, 15:00

Prof. Alex Fainstein, Instituto Balseiro and Centro Atómico Bariloche, Bariloche, Argentina

Time, place:

Wednesday, 15th February 2017, 15:00h

Seminar Room A1.500, MPL, Staudtstr. 2, 91058 Erlangen


Abstract:

Intense photon-phonon interaction derives from full spatial confinement of both optical and mechanical degrees of freedom, with quantum effects naturally manifesting when the system eigen-energies overcome the environmental temperature. So far optomechanical resonators could be pushed up to a few GHz, limited by nano-fabrication techniques and mechanical motion measurement methods. Here we report on the experimental study of semiconductor opto-mechanical resonators operating in the 20-100 GHz range. Micro-pillar cavities made of GaAs and AlAs, well known as optical resonators, are shown to confine in three-dimensions not only the optical field but also extremely high frequency acoustic phonons. A time-resolved transient optical refectivity technique with picosecond time resolution is implemented to access the energy spectrum as well as the dynamics of the involved mechanical modes. A strong increase of the optomechanical coupling upon reducing the pillar size is observed, together with room-temperature Q-frequency products attaining 1014. Transient dynamical phenomena that cannot be described with existent models is reported. This new platform for optomechanics can integrate single quantum emitters or polariton condensates, opening exciting perspectives at the frontiers of cavity quantum optomechanics and quantum electrodynamics. Prospects for enhanced polariton-mediated optomechanical coupling, and even higher operating frequencies, will be addressed.