The standard equations of thin film optics are applied to multiplate resonant reflectors of the kind used with ruby lasers. The numerical results show considerable disagreement with predictions based on approximate theory. A design is proposed that gives high reflectivity and is insensitive to thickness errors.
J. K. Watts, "Theory of Multiplate Resonant Reflectors," Appl. Opt. 7, 1621-1623 (1968)