Modes of a laser resonator with a retroreflective mirror

The self-consistent integral equation for the field distribution of the resonant modes in an inclined retroreflective grating resonator is solved in the limit of large Fresnel numbers. The transverse field distribution in the direction perpendicular to the grating grooves can be described in terms of Hermite-Gaussian functions provided that lambda << d << w, where lambda is the wavelength, d is the grating spacing, and w is the beam spot size.