Vapor control of resonant Zener tunneling of light in a photonic crystal

We show a vapor controlled one-dimensional photonic crystal built with a silicon-based dielectric mesoporous material, in which the refractive index can be continuously tuned by flowing organic vapors through the pores. Exposure of the crystal to vapors induces an inhomogeneous change in the refractive index through the depth and results in a tilted photonic band structure. We drive the photonic crystal to the optical Zener breakdown condition, introducing an enhanced transmission channel through the crystal. This phenomenon closely resembles the electronic Zener breakdown in a reverse-biased p-n junction. The effect is reversible and opens new perspectives for physics in photonic crystals and novel device concepts based on sensing, switching and processing of light. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.