Numerical investigation of one-dimensional nonpolarizing guided-mode resonance gratings with conformal dielectric films

We present the nonpolarizing resonance properties of two types of one-dimensional (1D) guided-mode resonance (GMR) gratings consisting of the sinusoidal-profile grating substrate and the conformal dielectric thin films. The optimization with respect to the grating height and the phase of the conformal graded-index layer is important for the design of nonpolarizing type-I GMR gratings. The thin films design of the conformal step-index multilayer and the optimization with respect to the grating height are of two critical steps to obtain the nonpolarizing type-II GMR gratings. Both of the two types of nonpolarizing GMR gratings can be designed to support single-mode resonance and multimode resonance under normal incidence.