Resonances of relief triangular gratings for terahertz input/output in А$_3$В$_5$ semiconductors

Diffraction efficiencies of relief semiconductor gratings in the terahertz range (THz) have been obtained by numerical modeling, and the properties of relief semiconductor gratings with a triangular symmetric profile of strokes have been considered. It is shown that three types of resonances are supported in such gratings: plasmon-polariton resonances (PPR), Rayleigh resonances, and resonances related to the stroke depth. The dielectric permittivity of InSb, GaAs and Al$_{0.3}$Ga$_{0.7}$As at a given temperature was taken from literature data or calculations using the Drude–Lorentz model taking phonons into account. It is found that lattices of this type, unlike lattices with other stroke profiles, exhibit very deep and narrow PDP resonances, as well as Rayleigh resonances.