Tightly Confined Surface Acoustic Waves as Microwave-to-Optical Transduction Platforms in the Quantum Regime

Published

September 26, 2022

Author(s)

Ryan DeCrescent, Zixuan Wang, Poolad Imany, Robert Boutelle, Corey McDonald, Travis Autry, John Teufel, Sae Woo Nam, Richard Mirin

Abstract

Surface acoustic waves (SAWs) coupled to quantum dots (QDs), trapped atoms and ions, and point defects have been proposed as quantum transduction platforms, yet the requisite coupling rates and cavity lifetimes have not been experimentally established. Although the interaction mechanism varies, small acoustic cavities with large zero-point motion are required for high efficiencies. We experimentally demonstrate the feasibility of this platform through electro- and opto-mechanical characterization of tightly focusing, single-mode Gaussian SAW cavities at ∼3.6 GHz on GaAs in the quantum regime, with mode volumes approaching 6λ^3. Employing strain-coupled single InAs QDs as optomechanical intermediaries, we measure single-phonon optomechanical coupling rates (g0) of 2π × 1.2 MHz, implying zero-point displacements >1.5 fm. In semi-planar cavities, we obtain quality factors >18,000 and finesse >140, the largest values reported to date on GaAs. To demonstrate operation at ultracold environments required for transduction of quantum states, we use a fiber-based confocal microscope in a dilution refrigerator to perform single-QD resonance fluorescence sideband spectroscopy showing conversion of microwave phonons to optical photons with sub-natural linewidths. Nominal device temperatures corresponding to an average thermal phonon occupation of 0.3. These devices approach or meet the limits required for microwave-to-optical quantum transduction.

Citation

Physical Review Applied

Pub Type

Journals

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https://doi.org/10.1103/PhysRevApplied.18.034067

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Keywords

Quantum dots, optomechanics, microwave-to-optical transduction

Citation

DeCrescent, R. , Wang, Z. , Imany, P. , Boutelle, R. , McDonald, C. , Autry, T. , Teufel, J. , Nam, S. and Mirin, R. (2022), Tightly Confined Surface Acoustic Waves as Microwave-to-Optical Transduction Platforms in the Quantum Regime, Physical Review Applied, [online], https://doi.org/10.1103/PhysRevApplied.18.034067, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=934694 (Accessed April 19, 2024)