Fiber-coupled photonic crystal resonators for an efficient single photon source

Abstract

Fiber-coupled photonic crystal resonators are proposed and investigated for realizing an efficient single photon source. Photonic crystal bandgap structures have drawn particular attentions due to their strong light confinement within a wavelength-scale volume, leading to possessing high Purcell factor. The abilities to adjust spectral resonance and spatial location of a photonic crystal micro-resonator relative to a single quantum dot are greatly demanded to demonstrate large Purcell factor which is essential to realize an efficient single photon source. Photon collection of the micro-resonator through an objective lens or an optical fiber must be high. The curved-microfiber is extensively exploited for the photonic crystal resonator in this study. The curved-microfiber efficiently collects photons from a single high Q/V cavity via evanescent coupling and offers abilities of relocation and spectral tuning. A photonic crystal micro-resonator is proposed that is relocatable in two dimensions. A wavelength-scale resonator with high Q-factor (26,000) and high collection efficiency (80%) is formed and repositioned by simply placing and relocating a curved-microfiber to a new position on the surface of a two-dimensional square lattice photonic crystal slab. The formation of the resonator was confirmed by observing lasing of resonators. Infrared microscope images showed that the lasing site is two-dimensionally relocated in-situ. Spectral tuning was demonstrated by modifying the curvature of the microfiber. Functionalities, such as the two-dimensional relocation, spectral tuning and efficient extraction, which the curved-microfiber coupling offers, may provide an alternative way of coupling with a single quantum dot. Various systems are investigated for relocatable photonic crystal resonator by coupling of the curved-microfiber. Triangular lattice photonic crystal slab supports the formation of resonator but large TM loss limits the Q-factor and the efficient photon...