Analytical calculation of the Q factor for circular-grating microcavities

An exact and compact analytical formalism has been developed to calculate the Q factor for circular Bragg resonators. The electromagnetic fields, energy, and power flow have been expressed analytically relying on the transfer matrix coefficients. The Q factor has been derived for both TM and TE polarizations. The proposed formalism is then compared with two numerical methods. © 2007 Optical Society of America.