Enhanced pathlength absorption measurements using optical waveguide structures

The central focus of this research was to devise methods to utilize the slab optical waveguide as a sampling geometry for quantitative enhanced pathlength absorption measurements. Studies were conducted both for analytes doped into polymer thin film waveguides and monolayers on top of the waveguide.;Initial experiments explored the possibility of controlling the coupling efficiency of the prism coupler by making the gap between the coupling prism and waveguide surface reproducible. The gap thickness was monitored using a reflectance technique. It was found that small variations in the gap thickness (;A multiple wavelength approach was found to be an effective method for separating the absorptive contribution from the experimental total attenuation. An absorption enhancement of 1.3 ;A multiple mode approach was investigated for its ability to separate the surface scatter contribution from the bulk attenuation. Again, the Pr;Enhancements in the measured monolayer absorption for the monolayer samples were on the order of 10...