Analytical theory of Wood anomalies under grazing light incidence

Although theory of Wood anomalies has a long history, starting from Raleigh's works, the complexity of the problem and wide set of possible applications of corresponding resonance effects (transformation of polarization, specular reflection suppression, energy transformation to waveguide or surface waves, nonlinear surface processes, etc.) in optics, optoelectronics, optical surface and gratings properties measuring, the problem still attracts investigators. The case of grazing incidence on the grating with period d much greater than the light wavelength k which we consider is a specific one because many diffracted waves are close to the plane surface eigenmode (surface polaritons), i.e. we are dealing with multiple linked resonances.