In this paper we numerically investigated the resonance optical response of the double waveguide gratings for green wavelength taking account the thermal effects. It was shown the thermo-optics effect has the main contribution for changing resonance wavelength and width of resonance spectral linewas estimated. The resonance response for passive and PT-symmetry modes. Obtaining results allow using such structure for temperature sensitive sensor applications.

The article describes an optical response of metastructure consisted of two optically coupled resonant subwavelength rectangular - profile diffraction gratings, between which a layer of optically transparent dielectric was placed. The features of optical resonance transmittance and reflectance for optical PT-symmetry mode was numerical investigated and some advantages of using optical PT-symmetry for resonance transmittance (reflectance) improving was demonstrated. The spectral characteristics of the metastructure change when the pumping level changes and when the system switches from the optical parity-time-symmetry mode to the broken parity-time-symmetry mode were analyzed too.

The article presents a study of the dependence of the change in the shape of the resonance transmission line for optical thin dielectric gratings. The result of changing the duty cycle for high and low medium contrast while maintaining the amount of substance has been demonstrated. The results of the effect of the filling factor on the resonance transmission width and the frequency position in the normal TE wave drop are numerically investigated. Results for various options of a angles of the falling bunch at various coefficients of filling are presented. The effect of refractive index contrast of this structure on the width and shape of resonance lines was analyzed. In the first approximation, effective refractive indices and effective thicknesses for such structures were calculated. Conclusions are drawn about the conditions under which the structure can be considered optically thin.