Highly dispersive photonic band-gap prism

We propose the concept of a photonic band-gap (PEG) prism based on two-dimensional PBG structures and realize it in the millimeter-wave spectral regime. We recognize the highly nonlinear dispersion of PEG materials near Brillouin zone edges and utilize the dispersion to achieve strong prism action. Such a PEG prism is very compact if operated in the optical regime, similar to 20 mu m in size for lambda similar to 700 nm, and can serve as a dispersive element for building ultracompact miniature spectrometers. (C) 1996 Optical Society of America