On-demand photonic crystal resonators

Recent progress in the field of re-locatable photonic crystal resonators is discussed with a particular emphasis on the flexible scheme that employs highly-curved microfiber. In this scheme a spectrally-tunable high-quality-factor resonator can be defined repeatedly by physically moving a curved microfiber to a new position. When a curved microfiber is placed on top of a photonic crystal waveguide (or photonic crystal), a photonic well is newly created in the vicinity of the contact point. Inside of this photonic well, high-quality-factor resonant modes are generated at frequencies below the cutoff edge of the guided mode. The tapered microfiber is an integral part of a single mode optical fiber and efficient out-coupling is naturally obtained. The sub-nanometer spectral tuning capability that is available by changing the curvature of the microfiber is also an important characteristic and discussed. This spectrally- and spatially-reconfigurable photonic crystal resonator is expected to be a potential platform for photonic crystal based single photon sources, which enables accurate spatial overlap and spectral overlap with a single quantum dot, together with straightforward photon out-coupling to the fiber with high efficiency.