Excitation of Fluorescent Emission from Solutions at the Surface of Polymer Thin-Film Waveguides: An Integrated Optics Technique for the Sensing of Fluorescence at the Polymer/Solution Interface

Abstract

In this paper we report a technique for the excitation and collection of fluorescence in a flow cell coupled to the surface of an integrated optical waveguide. The waveguides were 1–2–µm-thick poly(styrene) films spuncast onto acid-cleaned Pyrex® microscope slides. The flow cell was used to introduce fluorescent solutions to the light energy at the polymer waveguide surface. The flow cell volume consisted of a 0.051-cm-thick silastic gasket sandwiched between a glass collection window and the polymer waveguide surface. Fluorescence data from the waveguide surface excitation of fluorescein solutions are presented. Evanescent- and scatter-excited emissions are separated with the use of light attenuation theory. The application of polymer thin-film waveguides to the study of protein adsorption at the polymer/solution interface is discussed.