Abstract

Using planar waveguides as a platform for optical biosensors allows an efficient and selective fluorescence excitation in close proximity to the waveguide surface. Usually, the fluorescence light that is emitted in the space above the sensor chip is collected and analyzed by suitable free space optics and a detector. Due to the vicinity of the fluorescent molecules to the interface of the waveguide layer, a substantial part of the fluorescence light is coupled back into and collected by the waveguide. The coupling efficiency depends on position, environment and orientation of the molecules. The utilization of this signal for fluorescence detection and analysis can allow a significant simplification of the optical instrumentation. We present a fundamental investigation of the fluorescence collection efficiency into the waveguide by theoretical and experimental means.

© 2009 OSA/SPIE