The platform exploits hybrid opto-mechanical microcavities with semiconductor quantum wells, which are designed to simultaneously confine near-IR photons, quantum well excitons, and GHz phonons tightly in the same spatial region (the microcavity spacer, cf. Figure). The strong coupling between photons and excitons gives rise to hybrid light-matter exciton-polariton quasi particles, which strongly interact with phonons.
The epitaxial nanostructure enables high optical and acoustic quality factors (as well as long polariton and phonon amplitudes), which are important considerations for coherent control. An important feature of the platform is the electrical generation of highly monochromatic phonons by piezoelectric transducers fabricated on top of the microcavity. These transducers also act as efficient phonon detectors with a very large dynamical range. Finally, the design also takes advantage of is the almost-perfect acoustic reflections from the polished facets of the wafer. These reflections feed escaping phonons back into the spacer region, thus further enhancing the acoustic quality factor.
The strong phonon field within the spacer regions induces a very large spectral modulation of the energy (in excess of 10 meV) and strength of exciton-polariton resonances at frequencies up to 20 GHz. The energy modulation amplitudes far exceed the spectral linewidths as well as the exciton-phonon Rabi coupling. The electrically driven platform thus opens the way towards electrically driven polariton optomechanics in the sideband-resolved regime at GHz frequencies with an intrinsic interface to near-IR photons. Furthermore, the platform can be extended to the single particle, quantum regime by confining both polaritons and phonons in intra-cavity traps created defined in structured microcavities.
 Alexander S. Kuznetsov, Diego H. O. Machado, Klaus Biermann, and Paulo V. Santos, Electrically Driven Microcavity Exciton-Polariton Optomechanics at 20 GHz, Phys. Rev. X 11, 021020 (2021) https://link.aps.org/doi/10.1103/PhysRevX.11.021020
 Alexander S. Kuznetsov, Paul L. J. Helgers, Klaus Biermann, and Paulo V. Santos, Quantum confinement of exciton-polaritons in structured (Al,Ga)As microcavity, Phys. Rev. B 97, 195309 (2018) https://journals.aps.org/prb/abstract/10.1103/PhysRevB.97.195309