Controlling the emission of quantum dots embedded in photonic crystal nanocavity by manipulating Q-factor and detuning

Abstract

We investigated the modulation of the Purcell effect by controlling the $Q$-factor and detuning in a quantum-dot--nanocavity coupled system. The $Q$-factor and detuning are controlled independently using a nanocavity and a waveguide reflector formed in a two-dimensional photonic crystal (PC) slab, in combination with a newly developed nitrogen adsorption/desorption method that enables local control of the refractive index. For example, we observed that the emission of a quantum dot via a cavity mode was increased by 3.3 times when the $Q$-factor was changed from 3500 to 6900 while keeping the detuning fixed. The dependence of the Purcell effect on the $Q$-factor has thus been directly observed.