Coupling of quantum-dot light emission with a three-dimensional photonic-crystal nanocavity

We report on the first demonstration of the coupling of fully confined electrons and photons using a combination of three-dimensional photonic crystal nanocavities and quantum dots. The three dimensional photonic crystals were assembled by stacking planar components using a sophisticated micromanipulation technique. Point defects, containing embedded quantum dots, were introduced into the photonic crystals as active sites. By measuring the photoluminescence spectra of the assembly, the process by which light emitted from the quantum dots is coupled to the defect modes of a three dimensional photonic crystal was demonstrated for the first time. The characteristics of the sharp emission peaks agreed well with numerical simulations, and these were confirmed to be resonant modes by polarization measurements. The highest quality factor (Q-factor) for three dimensional photonic crystals (2,300) was achieved.