Analysis of longitudinal-field reflection in dielectric gratings

Because of a common approximation used in the derivation of the wave equation, conventional analyses of Bragg reflection from dielectric gratings do not account for the distinctive behavior of the longitudinal field component of the electric field. We address this issue, which has particular significance in subwavelength scale periodic dielectric structures. We discuss new reflection phenomena within the theoretical framework of coupled-wave analysis, supplemented with numerical calculations.