Angularly robust resonant reflection from corrugated slab waveguide by mode coalescence

Mode coalescence in a double-sided corrugated highindex dual-mode slab waveguide suppresses the spectral splitting of the normal incidence resonant reflection peak upon an angular offset. The resulting angular robustness enables this polarizationand wavelength-selective reflection effect to be used to optically process free-space light beams emitted by low coherence sources. KeywordsSlab waveguide, Grating, Resonant reflection