Abstract
We have fabricated IR-transmitting Ge waveguides as supported single crystals 30-100 μn in thickness. These waveguides are useful as internal reflection elements for evanescent-wave absorption sensing and spectroscopy, when used in conjunction with a Fourier transform infrared microscope. This combination affords great sensitivity to small numbers of IR-absorbing molecules near the waveguide surface, and is especially useful for analyzing thin coatings on small-area substrates. For example, we have selectively observed absorption bands, as high as 20x the noise level, from the adhesive layer of a 0.07 mm2 piece of Scotch tape without observing absorption from the backing. By comparing spectra taken using 70- and 30-μm thick waveguides, we demonstrate a clear increase in sensitivity to small samples with decreasing waveguide thickness.
Original language | English (US) |
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Pages (from-to) | 371-377 |
Number of pages | 7 |
Journal | Proceedings of SPIE - The International Society for Optical Engineering |
Volume | 3105 |
DOIs | |
State | Published - 1997 |
Externally published | Yes |
Event | Chemical, Biochemical and Environmental Fiber Senors IX - Munich, Germany Duration: Jun 16 1997 → Jun 18 1997 |
Keywords
- Attenuated total reflection
- Chemical sensor
- IR microscope
- ZnS coating
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Computer Science Applications
- Applied Mathematics
- Electrical and Electronic Engineering