Advances in Pockels-effect-based adiabatic frequency conversion in lithium niobate high-Q optical microresonators

Lithium niobate (LN) is a material with outstanding optical properties including large second-order nonlinear coefficients; strong linear electro-optic effects; and excellent transparency at visible and near infrared wavelengths. It is thus widely used for a range of optical frequency conversion techniques; recent examples comprise frequency combs [1] - [4] and tunable integrated optical parametric oscillators [5]. We recently demonstrated a novel frequency conversion method, Pockels-effect-based adiabatic frequency conversion (AFC), in a LN whispering gallery microresonator [6]. By applying a voltage pulse faster than the lifetime of the photons in the cavity, we change the resonator eigenfrequency and hence the frequency of the trapped light such that no threshold has to be overcome, no phase-matching conditions need to be fulfilled and no mode hopping can occur.