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Near-infrared raman spectroscopy of chalcogenide waveguides and application to evanescent wave spectroscopy of bio-assemblies

Abstract Chalcogenide glasses and films are excellent candidates for near-infrared guiding configurations in opto-e]ectronics due to the ir high transmission. Their photosensitivity allows waveguide creation by standard lithography or one- and two-photon writing. The near-infrared Raman spectra of a series of As-S(Se) glasses are analyzed using spectral deconvolution and correlated with the molecular structure. Contributions due to As­ (S,Se)3 pyramjdal subunits as well as homopolar Se-Se and S-S bonds are determined. Photoinduced molecular changes in waveguide structures are probed by Raman scattering employing guided mode excitation. A new approach is demonstrated to optically interrogate composite layers where a chalocogenide waveguide provides the substrate and the guiding layer for a biomolecular film whose Raman spectrum is desired. Hydrophilic chalcogenide surfaces were prepared by exposure to 0 ₂ plasma and characterized by XPS spectroscopy. Thin layers of the photo-active protein bacteriorhodopsin were deposited on As₂S3 waveguides and observed by scanning electron and atomic force microscopy. The evanescent wave excited near-infrared Raman spectrum is measured in-situ providing a molecular probe of the chromophore and the light-adaptedstate. This novel technique offers potential for protein monolayer characterization and bio-sensors.

Identiferoai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:honorstheses1990-2015-1472
Date01 January 2005
CreatorsPope, April
PublisherSTARS
Source SetsUniversity of Central Florida
LanguageEnglish
Detected LanguageEnglish
Typetext
SourceHIM 1990-2015

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