The Piezoelectric Influence on Adiabatic Frequency Conversion in Lithiumc Niobate Whispering Gallery Resonators

Changing the frequency of light is crucial for numerous technologies and can be achieved using various methods. Adiabatic frequency conversion (AFC) is a promising yet underexplored approach that enables nearly 100% conversion efficiency without requiring phase-matching, even at the single-photon level. In AFC, the light frequency is shifted by varying the optical length of a resonator, with intracavity light following eigenfrequency changes if these occur faster than the resonator's decay time [1]. Whispering gallery resonators (WGRs), with their ultra-high quality factors Q, efficient light confinement, and electro-optic tunability - particularly in lithium niobate (LN) - provide an ideal platform for implementing AFC. We previously demonstrated that AFC achieves highly linear frequency modulation of light in an FMCW-LiDAR setup [2].