Reciprocity principle and electromagnetic wave scattering by plano-chiral double-periodic array

The vector relation of field amplitudes of direct and reversed scenarios of wave diffraction by double-periodic array is derived from the Lorenz lemma. The hiorthogonality of polarization eigenstates of wave propagated in direct and reversed direction in wave channel formed by incident wave and diffraction order is shown. The facility of essential difference of polarization transforms at direct and reversed propagation in wave channel is established for the instance of planar chiral array.