Structural characterization of chalcogenide planar waveguide materials using near-infrared Raman spectroscopy

Chalcogenide glasses (ChG) based on As, S and Se are transparent in the infrared and have found applications in bulk, planar and fiber waveguide optical components. Due to their recent use in planar channel waveguide devices, a study to assess how structural variations imposed by processing conditions (film deposition) lead to changes in linear and nonlinear optical properties, is ongoing in our group. high resolution near infrared (NIR) (lambda = 890 nm) Raman spectroscopy has been employed to characterize changes in bonding between bulk glass specimens and glass in planar form. To obtain spectroscopic and spatially resolved information on chemical bonding, a microscope attachment has been constructed and is characterized as to its spatial resolution Measurements are presented on single layer films prepared using processing and illumination conditions such as those used in fabricating waveguide components. These data are discussed in comparison to spectra obtained on bulk glass materials.