2026-09-22T16:13:03Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/115764 2023-07-11 col_2142_5131 col_2142_8888 com_2142_5130 com_2142_8887 com_2142_234

Eden, James G Eden, James G Waldrop, Lara Dragic, Peter Fang, Kejie 2022-05 application/pdf en text Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-05-01 The student, Austin Steinforth, accepted the attached license on 2022-04-14 at 20:36. The student, Austin Steinforth, submitted this Dissertation for approval on 2022-04-14 at 20:54. This Dissertation was approved for publication on 2022-04-15 at 11:42. DSpace SAF Submission Ingestion Package generated from Vireo submission #17683 on 2022-11-14 at 09:57:02 Stable and unstable resonators within Fabry-Pérot optical cavities containing microlenses: laser arrays, low-coherence imaging, and fractal laser modes Steinforth, Austin William 2022-04-15 laser optics coherence imaging fractal microlens microsphere Fabry-Perot This work investigates Fabry–Pérot laser resonators that contain arrays of microlenses. The lenses locally stabilized the resonator, which enabled arrays comprising hundreds to thousands of independent microbeams to be generated from a single cavity of modest dimensions. When such beam arrays were used as illuminators for full-field imaging, they exhibited a reduced spatial coherence and increased angular diversity compared to a conventional, highly coherent laser. These factors resulted in speckle suppression that scaled as ~N^(−1/2), where N is the number of independent beams in the array. The short duration (< 10 ns) and high pulse energy (≥8 mJ) of the array emission made it possible to image targets that moved at speeds up to 300 m/s with high resolution and no motion blur, as well as targets that were far from the source and camera (≥5 m, at present), and when optically dense fog intervened the beam path. Regions in between the lenses behaved as unstable resonators and were found to exhibit fractal characteristics in their transverse electric field profiles. Families of modes were simulated for two specific resonator configurations, and higher-order fractal modes were generated experimentally for the first time. The fractal dimension of each mode was found to evolve as the field propagated through the cavity. Thesis eng https://hdl.handle.net/2142/115764 Copyright 2022 Austin William Steinforth Ph.D. Dissertation Electrical & Computer Engr University of Illinois at Urbana-Champaign Electrical & Computer Eng