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Browsing by Author "Kandas, Ishac L. N."

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    High quality factor silica microspheres functionalized with self-assembled nanomaterials
    Kandas, Ishac L. N.; Zhang, Baigang; Daengngam, Chalongrat; Ashry, Islam; Jao, Chih-Yu; Peng, Bo; Ozdemir, Sahin K.; Robinson, Hans D.; Heflin, James R.; Yang, Lan; Xu, Yong (Optical Society of America, 2013-09-01)
    With extremely low material absorption and exceptional surface smoothness, silica-based optical resonators can achieve extremely high cavity quality (Q) factors. However, the intrinsic material limitations of silica (e. g., lack of second order nonlinearity) may limit the potential applications of silica-based high Q resonators. Here we report some results in utilizing layer-by-layer self-assembly to functionalize silica microspheres with nonlinear and plasmonic nanomaterials while maintaining Q factors as high as 10(7). We compare experimentally measured Q factors with theoretical estimates, and find good agreement. (C) 2013 Optical Society of America
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    Irreversible adsorption of gold nanospheres on fiber optical tapers and microspheres
    Yi, Jihaeng; Jao, Chih-Yu; Kandas, Ishac L. N.; Liu, Bo; Xu, Yong; Robinson, Hans D. (AIP Publishing, 2012-04-01)
    We study the adsorption of gold nanospheres onto cylindrical and spherical glass surfaces from quiescent particle suspensions. The surfaces consist of tapers and microspheres fabricated from optical fibers and were coated with a polycation, enabling irreversible nanosphere adsorption. Our results fit well with theory, which predicts that particle adsorption rates depend strongly on surface geometry and can exceed the planar surface deposition rate by over two orders of magnitude when particle diffusion length is large compared to surface curvature. This is particularly important for plasmonic sensors and other devices fabricated by depositing nanoparticles from suspensions onto surfaces with non-trivial geometries. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3701730]