| dc.description.abstract | Micro and nanofabrication techniques have revolutionized medical and pharmaceutical industries by their ability to mass fabricate biomedical devices with complex functionalities and geometries. 3D microsystems have significant advantages over 2D microsystems in better optical, electrical, mechanical, and biological properties in a much compact domain. Conventional 3D microstructures are fabricated by layer-by-layer stacking 2D fabrications, also known as 2.5D fabrication (micro stereolithography, micro laser sintering, electron beam lithography, etc.), or by direct 3D fabrication (holographic lithography, single spot multiphoton lithography). But these techniques have few or more limitations based on the type of fabrication materials, cost, process time, experimental setup constraints, and final resolution. For a fast throughput 3D microfabrication with good spatial resolution, this study proposes a new photolithography technique based on 3D light-field imaging principles. 3D light field projection is achieved with a spatial light modulator and a microlens array to direct light-rays to designed voxel positions in 3D space. Femtosecond light of high intensity is chosen as the light source for such precise microfabrication. Unlike single-photon absorption in UV light which causes unwilling curing of resists along the optical path, femtosecond light rays can accurately cure designed focal spots in 3D space through two-photon absorption. Due to the premature intersection of light rays before arriving at a voxel location, unwanted voxels are generated, which causes a mismatch between designed and fabricated microstructures. This thesis work mainly focuses on addressing this issue by improving the voxel generation algorithm to reduce unexpected voxels and ensure accurate high-speed patterning of simple microstructures with potential applications in biomedical sciences. | |
