Nonresonant Excitation Inside an Ultrahigh- $Q$ Nanocavity

Achieving on-chip optical wavelength conversion is a long-pursued object with fundamental difficulty in integrated photonics. As a step toward this goal, we theoretically and numerically demonstrate that wavelength conversion can be realized in a high-Q photonic crystal nanocavity, without any phase matching and high power requirement. The wavelength conversion efficiency of nearly 100% is achieved for a broad conversion range, and the mechanism is attributed to the dynamic interaction between the trapped light and an ultrahigh-Q cavity.