First-principles method for high-Q photonic crystal cavity mode calculations

We present a first-principles method to compute radiation properties of ultra-high quality factor photonic crystal cavities. Our Frequency-domain Approach for Radiation (FAR) can compute the far-field radiation pattern and quality factor of cavity modes ∼ 100 times more rapidly than conventional finite-difference time domain calculations. We explain how the radiation pattern depends on the perturbation used to create the cavity and on the Bloch modes of the photonic crystal.