The cavity of a laser with an interferential–polarizational filter based on phase interferometers

It is proposed to use the phase properties of a reflective interferometer upon oblique incidence for spectral selection in lasers. The effect is achieved due to the difference in phases of waves having different polarization and reflected from the reflective interferometer. A simple version in which the wave is incident at the Brewster angle on the reflective interferometer in the form of a plate with a single totally reflecting face is considered for several materials of the plate. It is shown that one such element can replace several plates of Lyot-type filters. A cavity with two reflective interferometers has been calculated; in this cavity, one can multiply increase the selectivity. A version of a cavity with a reflective interferometer in the form of a thin-layer coating is considered; for this cavity, a mechanism for a twofold increase in the free dispersion region due to inclusion of a metal layer into the coating is proposed. Results of calculating a specific device for a wavelength of 0.6 $\mu$m are presented.