Laser Holographic Fabrication of Three-Dimensional Photonic Crystal Templates Using Advanced Phase Mask Techniques

Three dimensional (3D) photonic crystal has attracted enormous interest in the last decade in both science and technology communities. Its unique capability to trap photons offers an interesting scientific perspective and can be useful for optical communication and sensing. However, the fabrication of large-scale 3D photonic structures at sub-micron scale with optimal photonic bandgap (PBG) remains a great challenge. Considerable efforts have been dedicated to develop fabrication techniques to produce large area defect-free 3D photonic structures toward device applications. This part of research need to develop a CMOS-compatible, laser interference lithography technique to produce 3D photonic structure on-chip using single- or multiple- layer diffractive optical elements (DOE). The DOEs can be incorporated into phase/amplitude masks used in optoelectronic circuit fabrications to enable a full integration of 3D photonic structures on-chip. Presented in this dissertation is the study of novel fabrication approaches of 3D photonic crystal. Compare to others, our studies utilize phase masks to fabricate 3D diamond-like photonic crystal templates in SU8 photoresist. 3D woodpile structures were fabricated by a double-exposure of SU8 to a three-beam or five-beam interference pattern generated by phase masks. Lattice structures and the PBG can be controlled by the rotational angles and relative displacement of the phase mask between exposures. Also, by using a single optical element such as special designed prism or phase mask, we demonstrate the phase tunability in the laser holographic patterning of 3D photonic crystal and quasi-crystal lattice structures. Photonic band gap computation predicts the existence and optimization of a full band gap in fabricated structures. The current studies demonstrate a simple and flexible approach to fabricate 3D photonic crystals with complex structures. It also lays solid ground work toward integrated fabrication of 3D photonic crystal structures on other optoelectronic components