Date of Award
Master of Engineering (ME)
Electrical and Computer Engineering
Dr. Judson Ryckman
Dr. Apoorva Kapadia
Dr. William Harrell
Due to the drawbacks of traditional refractive optics, the implementation of planar or nearly planar optical devices has been of research interest for over a century. Subwavelength gratings are a particularly promising option for creating flat optical devices; however, the implementation of subwavelength grating-based optics is limited by fabrication constraints. Recently, we implemented flat optical devices using the nanoimprinting of refractive index (NIRI) process, a process which was pioneered in a previous study but remained largely unproven in terms of device fabrication. The planar, gradient index microlenses we fabricated were found to possess an effective medium similar to a subwavelength grating. We determined that the gradient index planar microlenses successfully focused collimated incident light with focal full-width-half-maximums of less than 14 μm at wavelengths as low as 406 nm. We also fabricated digitally patterned waveguides between 0.35 and 2 μm in width using the NIRI process. We found a propagation loss in the non-oxidized waveguides of 8.1 ± 0.245 dBm/mm, which we were able to reduce by roughly 8 times following a full oxidation of the waveguides.
Hardison, Anna, "Digital and Gradient Refractive Index Planar Optics by Nanoimprinting Porous Silicon" (2022). All Theses. 3849.