Holographic fabrication of azo-dye-functionalized photonic structures

Abstract

We have developed an azo-dye-doped acrylate-based material formulation for holographic lithography. Volume phase gratings and two-dimensional photonic crystals were demonstrated by recording the interference patterns of two and three coherent beams in this material formulation. The dependence of the first-order Bragg diffraction efficiency of the gratings on the exposure intensity of the writing light was investigated. We have achieved a volume phase grating with a diffraction efficiency of 72%. These azo-dye-functionalized photonic structures showed an excellent all-optical switching behaviour, which was attributed to the imaginary refractive index changes caused by the trans–cisisomerization-induced absorption changes of the azo-dyes. Such photonic structures are potentially useful in the future development of all-optical devices.