Frequency selectivity of a multimode waveguide gas laser with a diffraction grating

Theoretical and experimental investigations were made of the frequency selectivity of dispersive resonators for waveguide gas lasers with diffraction gratings. The calculation method developed for resonators handling linear polarization can be used to study the properties of open single-mode, few-mode, and multimode waveguide resonators without frequency selection. The results of an experimental study of the frequency selectivity of a multimode waveguide laser are reported. These results agree with calculations. An analysis is made of the influence of the total resonator length and of the lengths of its components, as well as of the waveguide channel diameter and waveguide material on the selectivity. The results are given in terms of general scaling relationships so that they can be applied to cases characterized by a wide range of geometric dimensions and various relative positions of the resonator components.