Diffraction-compensated dispersion-accumulated superprism based on two cascaded photonic crystals

The combination of two planar photonic crystal areas is proposed to circumvent some limitations frequently encountered when using the so-called superprism effect, and especially the beam broadening phenomenon that accompanies strong prism spatial dispersion. The basic idea that is pursued is to choose two strongly dispersive photonic crystals but arrange their properties to make their diffraction effects cancel out as a whole. In-depth investigation of a possible global configuration is performed by using Plane Wave Expansion simulation and post-processing calculations to estimate second order dispersion parameters that govern both dispersion and diffraction. A two photonic crystal structure is chosen and the predicted dispersion-accumulation and diffraction-compensation mechanism is verified using Finite Difference Time Domain simulation.