Direct extraction of large quality factors and resonant frequencies from Pad, interpolated resonance spectra

Extracting the quality factor and resonant frequency of photonic crystal resonators simulated using the finite-difference time-domain algorithm is investigated. The Pad, interpolation method is applied to the resonance spectra, and closed form expressions for the quality factor and center frequency in terms of the coefficients in the Pad, function are presented. The method is applied to simulations of the photonic crystal double heterostructure cavity.