Dihedral optical resonators and prism beam waveguides.

A simple theory is developed for optical resonators, in which the mirrors are each composed of two planes forming a nearly straight dihedral angle and an equivalent beam-waveguide comprising a sequence of narrow angle prisms. Geometric optical considerations yield the variation of the intensity within the resonator in a manner analogous to (although not entirely as satisfying as in) the case of the spherical mirror resonator. Modes of the continuous medium, identified as the limit of particular sequences of closely spaced weak prisms, characterized by a parameter Omega, are found in terms of Airy functions. An appropriate spot size parameter is given by [Omega/2k0(2)]1/3, where k(0) is the wavenumber.