Generation of a wave with a frequency $3\omega_1-\omega_2$ on reflection from the isotropic gyrotropic medium surface

The generation of a reflected wave with a frequency of $3\omega_1-\omega_2$ under inclined incidence of two elliptically polarized plane waves with frequencies $\omega_1$ and $\omega_2$ on the surface of an isotropic gyrotropic medium is studied. It is shown that the generation is most efficient in grazing reflection of the wave with a frequency $3\omega_1-\omega_2$. It is found that there exist such incidence angle ranges wherein the reflected wave becomes nonuniform, and its amplitude decreases exponentially with distance from the medium surface.