Time-resolved optomechanical dynamics of In(Ga)As quantum dots modulated by surface acoustic waves

Surface acoustic waves (SAW) are an attractive platform for coupling to a variety of quantum systems, including superconducting qubits [1, 2], defect spins in diamond [3, 4], and optically-active InGaAs quantum dots (QDs) [5]. Here, we demonstrate the enhanced optomechanical coupling between a planar SAW cavity driven by superconducting electronics and single QDs transferred onto a strongly piezoelectric substrate, LiNbO₃, via epitaxial lift-off [6]. Using time-correlated single-photon counting, we resolve the temporal dynamics of the modulated QD exciton transition under coupling to various SAW cavity modes, showing energy-level splittings consistent with strain modulation via the GaAs deformation potential. Analysis of the dynamics versus SAW frequency may show evidence of novel acoustic-drive wave mixing. These results point to the potential for SAW electro-optomechanics in a multifunctional integrated platform that combines phononic, optical, and superconducting electronic quantum systems.

[1] Nature 563, 661-665 (2018), [2] Phys. Rev. X 9, 021056 (2019), [3] Nat. Comm. 11, 193 (2020), [4] Phys. Rev. X 6, 041060 (2016), [5] J. Phys. D 51, 373001 (2018), [6] Appl. Phys. Lett. 56, 2419-2421 (1990)