Fabrication of 3D Photonic Structures by Holographic Lithography
Advances in nanoscience and technology increasingly rely on the availability of complex 3D structures with nanometer resolution. Laser-based non-conventional lithographic techniques are suitable for the large-scale fabrication of 3D structures with well-controlled shapes, fine (submicron) features, and tailored chemistries. These complex 3D structures will find potential applications in photonics, microfluidics and tissue engineering. Novel materials as photoresists and chromophores that are highly sensitive and tailored for specific systems will be synthesized. We are interested in creating complex 3D structures that are technologically important but not accessible by other methods.
One specific example is 3D photonic crystal (PCs) with periodically alternating high- and low-dielectric constant materials, which offer extraordinary control of the propagation of photons within a specific range of frequencies. Guided by theoretical calculation, we have pioneered a non-conventional lithographic procedure based on interference lithography (IL) of multiple visible laser beams to create a wide-range of 3D PCs. One major challenge is to fabricate high refractive index contrast for large, complete photonic bandgaps. Through rational design of the photochemistry and surface chemistry, we investigate various protocols for double and single templating toward high index materials (e.g. TiO2 and Si), including wet vs. dry filling, and chemical displacement. We then study the fidelity of backfilling and its influence to the optical and mechanical properties of the films.
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Moon, J. H.,Dong, W. Adibi, A. Perry, J. W. , Yang, S.-M., Yang, S.* , “ Core-Shell Diamond-like Silicon Photonic Crystals from 3D Polymer Templates Created by Holographic Lithography”, Opt. Express, 2006,14, 6297. DOI.
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