Holographic photonic structures generated in dichromated pullulan

Holographic method was used to fabricate volume Bragg gratings, i.e., 1-D photonic crystals, in dichromated pullulan (DCP). Wide and complete band gaps were obtained in transmission spectra of light from the halogen lamp. SEM images of cross sections of DCP film show large voids right under the film surface, followed by regularly spaces bright and dark regions of Bragg grating filled with nano-size air voids. This work presents potentials of DCP as a material for photonic crystals, which so far has not been used for generation of photonic crystals.