MINIATURIZED SPECTROMETER EMPLOYING PLANAR WAVE-GUIDES AND GRATING COUPLERS FOR CHEMICAL-ANALYSIS

Polymeric and metal oxide planar waveguides were used to demonstrate the potential of a miniature spectrometer. Multiwavelength light was transmitted through the substrate and coupled into the waveguide through a diffraction grating located at the substrate/waveguide interface. A second diffraction grating spatially dispersed the light propagated through the waveguide into component wavelengths for rapid analysis with a photodiode array detector. These results suggest that planar waveguides can be used to perform attenuated total internal reflection measurements in the visible and near-IR regions for chemical analysis of weak vibrational overtones and combination modes with effective path lengths of several millimeters. © 1990 Optical Society of America.