Investigation of open resonators with rectangular inhomogeneities on the mirror

An analysis is presented of a semisymmetric open resonator with extended rectangular inhomogeneities on the plane mirror in the form of a groove, jut, and step with transverse dimensions comparable with the wavelength and longitudinal dimensions exceeding the limits of the field spot on the mirror. The measured dependence of Q-factor on groove dimensions is compared with the dependence calculated by solving the problem of the diffraction of an H-polarized wave by a plane mirror with such a groove; and good agreement is found. Experimental results show that inhomogeneities in the groove excite an electromagnetic wave that propagates along the groove. The effect of this wave on losses in the resonator is assessed.