A tunable three layer phase mask for single laser exposure 3D photonic crystal generations: bandgap simulation and holographic fabrication

Abstract

Through the use of a multi-layer phase mask to produce fivebeam interference, three-dimensional photonic crystals can be formed through single exposure to a photoresist.In these holographically formed structures, the interconnectivity is controlled by the relative phase difference among contributing beams.Photonic band gaps are calculated and the simulation shows a maximum bandgap of 18% of the middle gap frequency when the phase difference is optimized.A three-layer phase mask is fabricated by placing a spacer layer between two orthogonally-orientated gratings.The phase difference is controlled by thermal-tuning of the spacer thickness.Photonic crystal templates are holographically fabricated in a photosensitive polymer using the phase mask. ©2011 Optical Society of America