Superprism phenomena in polymeric woodpile structures

An analysis of the optical properties of photonic woodpile structures is presented. We demonstrate large superprism phenomena inside polymeric woodpile structures having a refractive index of less than n=1.6. Due to the low contrast in refractive indices the structures investigated do not possess a complete photonic band gap. Nevertheless, their photonic band structures show strong anisotropy at frequencies slightly above the band gap in the (Г-X) direction, leading to an extreme sensitivity to the angle and the frequency of the incident light in the propagation direction inside the crystal. Furthermore, if the woodpile structure is arranged in a prism-like shape, the transmitted beam outside the crystal shows a strong sensitivity to the frequency and angle of the incident light.