Tuning of nanocavity optomechanical coupling using a near-field fiber probe

Optomechanical coupling in a nanocavity formed between two cantilevers is tuned through renormalization of the nanocavity field, allowing reconfiguration of the dominant optomechanical transduction mechanism and spatially selective optical readout of mechanical resonances. Tuning is mediated through evanescent interaction between the nanocavity and a fiber taper near-field probe that induces both dissipative and dispersive optomechanical coupling. Tunable optomechanical coupling can exceed 3 GHz/nm, and is shown to allow readout of out-of-plane cantilever nanomechanical resonances suitable for sensing applications. (C) 2015 Optical Society of America.