The excitation of a concave optical resonator with one planar mirror by a laser source incident normally on the planar mirror is described. The problem is analyzed by describing the resonator fields by both ray tracing and normal mode analysis. The latter is more general, but it is shown that in the appropriate limit the two methods of analysis yield nearly identical solutions. Main emphasis in the analysis is placed on determination of the reflection coefficient, relative mode amplitudes, and field patterns. These are the parameters that are of interest to users of the scanning interferometer and the coupled cavity laser interferometer. The latter is commonly used to diagnose gaseous plasmas.
Joseph T. Verdeyen and James B. Gerardo, "Off-Axis Excitation of the Coupled Cavity Spherical Laser Interferometer," Appl. Opt. 7, 1467-1476 (1968)