Polariton path to fully resonant dispersive coupling in optomechanical resonators

Abstract

Resonant photoelastic coupling in semiconductor nanostructures opens new perspectives for strongly enhanced light-sound interaction in optomechanical resonators. One potential problem, however, is the reduction of the cavity Q-factor induced by dissipation when the resonance is approached. We show in this letter that cavity-polariton mediation in the light-matter process overcomes this limitation allowing for a strongly enhanced photon-phonon coupling without significant lifetime reduction in the strongly-coupled regime. Huge optomechanical coupling factors in the PetaHz/nm range are envisaged, three orders of magnitude larger than the backaction produced by the mechanical displacement of the cavity mirrors.Optomechanical resonators, that is, cavities that confine light and mechanical vibrations in the same space, strongly coupling the electromagnetic and elastic deformation fields, have emerged as novel paradigms for new fundamental ideas and applications.1-11 Optomechanical non-linearities, laser cooling, and phonon lasing 12,13 have been demonstrated. In addition, optomechanical devices have been cooled down to the quantum ground state of mechanical motion, signaling a new era of quantum phononics with implications for quantum information processing, sensitive measurements and fundamental research.14-17 Very recently hybrid systems combining cavity quantum electrodynamics (CQED) and cavity optomechanics have been theoretically proposed as a means to evidence unconventional dissipative couplings and cooling at the single-polariton level.18,19 Here we experimentally demonstrate an additional relevant characteristic of cavity polariton optomechanics, i.e., the possibility to access a hugely enhanced optomechanical coupling of dispersive photoelastic resonant nature, without significant dissipation-induced cavity Q-factor quenching.Two issues that have been identified as relevant for the development of cavity optomechanics are, on one side, the push for ever higher frequencies [20][21][22] and, on the other side, the search for new stronger optomechanical coupling mechanisms.22-25 While micromechanical devices typically oscillate in the KHz-MHz range, GHz-THz frequencies have been attained using nano-size toroids 21 and distributed Bragg reflector (DBR)-based microcavities. 22Radiation pressure is usually identified at the origin of optomechanical coupling. Direct transfer of impulse from the photon field to the resonator mirrors induces vibrations on the latter, which in turn results in a backaction on the electromagnetic field due to the resonator optical detuning induced by the mechanical displacement of the mirrors. We have recently reported that GaAs DBR- * email:afains@cab.cnea.gov.ar based microcavities constitute optimized optomechanical resonators operating in the GHz-THz range, with the potential of adding an additional photoelastic term to the above described purely "mechanical" mechanism.22 The two complementary sides of the coin in this case are electrostriction (for the generation of phonons by ligh...

Indirect strong coupling regime between a quantum emitter and a cavity mediated by a mechanical resonator

“…Large optomechanical coupling rates and photon-phonon strong coupling regime have been achieved in different systems, particularly in photonic crystals and micropillars [5,4]. Besides, active media have been used to enhance optomechanical coupling [22,13,26]. Furthermore, it is well known that linear coupling between cavity and mechanical resonators raises in the socalled resolved sideband regime [31,1,9], i.e., when phonon energy is larger than the cavity decay rate (ω m > κ), in that regime the cavity is pumped by a large coherent field.…”

Fabry-Pérot-multichannel spectrometer tandem for ultra-high resolution Raman spectroscopy

“…8, and has been used to study the lifetime and mode broadening of planar semiconductor acoustic cavities 29 for the last few years. 8,30 We will present here two examples of these results to show the capabilities of the FP/triple spectrometer/CCD tandem regarding energy range and resolution. Both examples were acquired using the gas pressure tuning method.…”

Quantum well photoelastic comb for ultra-high frequency cavity optomechanics

“…It turns out that below the absorption gap photoelastic mediated electrostrictive forces can become the leading contribution if electronic resonances are approached with continuous wave (cw) in hybrid optomechanical resonators containing direct bandgap materials as for example GaAs. 17, 28,29 In these Brillouin-Raman processes no real excitation of electron-hole pairs, as in Ref. 27, occurs.…”