On losses and spatial mode characteristics of a wide-aperture Fabry–Perot resonator upon a periodic spatial perturbation of the field phase at one of the mirrors

The losses and spatial mode characteristics of a wide-aperture Fabry–Perot resonator are studied upon a periodic spatial perturbation of the radiation-field phase in a thin layer adjacent to one of the resonator mirrors. It is shown that two regions with different perturbation scales, which affect the losses and distortions of the spatial characteristics of the first modes, are formed for a given perturbation amplitude in the general case.