BROADBAND COUPLING INTO SINGLE MODE, PLANAR INTEGRATED OPTICAL WAVEGUIDE STRUCTURES FOR SPECTRAL ANALYSIS OF THIN FILM ANALYTES AND INTERFACIAL CHEMICAL ENVIRONMENTS
AuthorBradshaw, John Thomas
Thin Film Analysis
Committee ChairSaavedra, S. Scott
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractA broadband coupling approach applied to a single mode, sol-gel, planar integrated optical waveguide (IOW) was used to create a multichannel attenuated total reflection (ATR) spectrometer. Initial attempts to create an achromatic coupling element for sol-gel waveguides, based upon previous work applied to vacuum deposited glass devices, did not lead to an easily achievable design. Instead a simplified, non-achromatic approach based upon impinging an incident light beam with a large numerical aperture onto an incoupling prism was used. This simplified broadband coupling approach was used to create a sol-gel IOW-ATR spectrometer that transmitted light down to at least 400 nm, and produced a measurable bandwidth of ~ 250 nm; both phenomena are marked improvements upon the capabilities of previously reported devices. An experimental demonstration of this device proved it capable of measuring the visible spectrum of a thin film of horse heart cytochrome c adsorbed to the sol-gel surface at a submonolayer coverage. The broadband spectral capabilities of this sol-gel device were also used to experimentally validate a new method for determining the angular orientation of molecules bound to an arbitrary waveguide surface. In addition to the sol-gel IOW work, the simplified broadband coupling approach was applied to a previously reported multilayered electroactive waveguide device, which was used to collect electrically modulated, broadband spectra for thin films of cytochrome c, as well as a dicarboxyferrocene moiety. Both of these IOW-ATR spectrometers represent improved tools for probing the near-surface chemical environments of molecular assemblies.