Investigation of the dynamic features of a moveable ultrahigh-Q nanocavity

Abstract

Although the approach of forming an ultrahigh-Q nanocavity via local refractive index tuning in a PC waveguide was proposed a decade ago, it has not yet been employed to realize a moveable ultrahigh-Q nanocavity, thereby the dynamic physics related to a moving resonator remain unknown. Here we demonstrate that a dynamically-formed cavity is essentially moveable, so that we can use this nanocavity to trap, store, and transfer signal photons, enabling free photon control. For a high cavity moving speed, we find the trapped signal energy will radiate out of the moving cavity. We think this interesting phenomenon originates from Doppler-effect-induced resonant frequency split in a moving resonator and the accompanied change of energy capacity. In addition, we present an analytical model to reveal why and how the trapping and storing processes are accompanied by significant spectral bandwidth compression and dynamic wavelength conversion, which are critical for achieving dynamic ultrahigh-Q nanocavity. This approach may find application in photon memories, quantum computing, and controllable light-matter interactions.