Light trapping by thin periodic planar structures

The problem of visible and IR light diffraction by planar 2-D periodic metal-dielectric structures with a periodic cell consisted of two complex-shaped asymmetric metal elements was solved. The mapped PSTD method and ADE technique with complex-conjugate pole model were used for taking into account the dispersion of metal permittivity. The conditions of light confinement by an excitation of trapped mode resonances of the structures were studied. Existence of high order trapped mode resonance with a greater quality factor than the quality factor of lowest one was shown for the first time.