High-impedance Surface Acoustic Wave Resonators on Lithium Niobate

Surface acoustic wave resonators (SAWR) formed by defining two grating-like-mirrors on the surface of piezoelectric materials are useful in various classical and quantum applications. They are robust against magnetic fields and stray photons, can operate from room temperature to cryogenic temperatures, and have low loss. We fabricate high-frequency SAWRs on lithium niobate with Gaussian mirrors and characterize them at various temperatures. The cavity stopband and the thickness of electrodes are optimized for a high quality factor and small mode area for large zero-point fluctuations. Because of the large phonon lifetime and high characteristic impedance, these surface acoustic wave resonators are promising candidates for quantum state transduction.