Characterization of defect modes in finite bidimensional photonic crystals

We study finite-size bidimensional photonic crystals doped by a microcavity. We characterize the defect modes by developing a simple model of an infinitely conducting cavity. This model allows the prediction of the number of defect modes and their evolution Versus the conicity angle. Finally, we present a method for the computation of the quality factor of the microcavity by means of the poles of the scattering matrix. We demonstrate numerically that the quality factor grows exponentially with respect to the size of the crystal. These results obtained in the frequency domain are checked by solving MaxwelI's equations in the time domain. (C) 1999 Optical Society of America [S0740-3232(99)02510-7].