Multifunctional blazed gratings for multiband spatial filtering, retroreflection, splitting, and demultiplexing based on <i>C</i>₂ symmetric photonic crystals

The concept of multifunctional reflection-mode gratings that are based on rod-type photonic crystals (PhCs) with [Formula: see text] symmetry is introduced. specific modal properties lead to the vanishing dependence first-negative-order maximum angle incidence and nearly sinusoidal redistribution incident-wave energy between zero order (specular reflection) first negative diffraction (deflection) at frequency variation. These features key enablers diverse functionalities merging different into one structure. elementary functionalities, which scenarios can be designed, include but not restricted multiband spatial filtering, splitting, retroreflection, demultiplexing. proposed structures capable operation in case a single polychromatic incident wave or multiple mono-/polychromatic waves angles. generalized demultiplexing possible several waves. aforementioned deflection yield splitting functionality. In turn, it may contribute more complex scenarios. Finally, PhC studied transmissive configuration, they show some unusual properties.