Photonic crystal κ-vector superprism

We theoretically investigate the resolution of the photonic crystal (PC) superprism as a narrow-band filter at 1.55 μm wavelength range. First, we defined the equi-incident-angle curve against the dispersion surface of each photonic band in the Brillouin zone and calculated the beam collimation, wavelength sensitivity, and resolution parameters for a PC. The result indicated that the conventional superprism which deflects the Poynting vector of light cannot achieve a high resolution and the miniaturization of the PC, simultaneously. So, we proposed a new superprism (κ-vector prism), which deflects the κ vector and enhances the refraction angle at an angled output end of the PC. We estimated that the resolution is the same as or higher than that of the conventional prism and the PC can be significantly miniaturized. Through the finite-difference time-domain simulation of light propagation, we observed a correspondence and a characteristic difference against the above analysis.