Holographic fabrication of three-dimensional orthorhombic and tetragonal photonic crystal templates using a diffractive optical element

We report the fabrication of both orthorhombic and tetragonal photonic crystal templates using a phase mask technique. Three-dimensional photonic crystal structures were formed by a double exposure of SU8 to three-beam interference patterns generated by a phase mask. Lattice structures and photonic band gap can be controlled by rotational angles of the phase mask between two exposures. Band gap computation predicts that photonic crystal structures with the optimized band gap can be realized when the rotational angle is set between 50 degrees and 70 degrees. A photonic crystal template with 60 degrees phase mask rotation was fabricated, showing improved lattice structures required for the band gap opening. (c) 2007 American Institute of Physics.