2026-09-21T16:56:55Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/24336 2023-07-10 col_2142_14787 col_2142_5131 com_2142_9630 com_2142_234 com_2142_5130

Copyright 2011 Kaspar D. Ko optics photonics near-field enhancement field enhancement field confinement nano-antenna nanophotonics laser-induced damage plasmonically enhanced optical trap optical tweezers Toussaint, Kimani C. Ko, Kaspar D. 2011-05-25T14:53:34Z 2011-05-25T14:53:34Z 2011-05-25T14:53:34Z 2011-05 This thesis investigates the effects of the large near-field intensity enhancements from periodic arrays of gold bowtie nano-antennas (BNAs) after illumination by laser light. Specifically, we focus on laser-induced damage, nonlinear optical emission, and a proof-of-concept for utilizing arrays of gold BNAs to enhance the forces in an optical trapping system. From FDTD simulations, the optical response of a single BNA is demonstrated to increase the local intensity by a factor of 1000 in the feed-gap region by using a periodic array. Because of the high near-field intensities, inherently weak nonlinear optical processes become enhanced, and we take advantage of these favorable conditions to investigate the dependence of second-harmonic generation and two-photon photoluminescence emission intensities with respect to the array periodicity and the incident polarization. A detrimental side-effect of the efficient radiative coupling to the incident light and high near-field intensities is laser-induced damage, which may alter the morphology of the BNA structures at sufficiently high laser fluences. A damage threshold is systematically determined in terms of irradiation time and average incident power after implementation of damage reduction measures including laser pulse-width optimization, a stochastic beam-scanning pattern, and the use of a chromium adhesion layer. Finally, the increased optical forces in a trapping system resulting from the field enhancement of arrays of BNAs is demonstrated. In addition, based on the exclusive behaviors of these types of systems, a new method of characterizing plasmonically enhanced optical traps is proposed. Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2011-04-29T18:44:10Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 2 Ko_Kaspar_LatexBuild.tex: 6217 bytes, checksum: f5ef29a7df37f2c35cffaef85f4296b9 (MD5) Ko_Kaspar.pdf: 20008263 bytes, checksum: 43512054661bbd47f02bb5c78c3e58e6 (MD5) Made available in DSpace on 2011-05-25T14:53:34Z (GMT). No. of bitstreams: 3 Ko_Kaspar.pdf: 20008263 bytes, checksum: 43512054661bbd47f02bb5c78c3e58e6 (MD5) license.txt: 4056 bytes, checksum: cdb629e9197e97b7daafb2aa87305bd8 (MD5) Ko_Kaspar_LatexBuild.tex: 6217 bytes, checksum: f5ef29a7df37f2c35cffaef85f4296b9 (MD5) http://hdl.handle.net/2142/24336 en second-harmonic generation gold nanostructure two-photon photoluminescence supercontinuum generation bowtie nano-antenna periodic arrays array effect resonant enhancement trampolining trapping regime nano-dimers coupled-plasmon resonant-nanoparticle pair geometry Nonlinear optical emission and near-field enhancement effects in arrays of gold bowtie nano-antennas Mechanical Sci & Engineering 1917 Mechanical Engineering 0133 University of Illinois at Urbana-Champaign Thesis M.S. MS:Mechanical Engineerng -UIUC 10KS0133MS