SBIR-STTR Award

This research is to develop a Raman spectrometer based on small-diameter, long-path length, totally-internally reflecting sample cells. The cells will be hollow fibers drawn from a transparent amorphous fluoropolymer with a refractive index less than water. These fibers will act as optical fibers when filled with any transparent liquid. This will confine the excitation and Raman-scattered radiation within the sample, increasing the Raman intensity by as much as 3 to 4 orders of magnitude. Raman spectrometers are used extensively in analytical chemistry primarily to provide information on molecular vibrations. The results of this research will make the Raman spectrometers even more useful to industry by increasing the intensity of conventional spectrometers and extending their use to essentially all transparent liquids.

This Small Business Technology Transfer Phase II project will produce a Raman spectrometer based on the use of liquid core optical fibers to enhance signal intensity and improve signal-to-noise ratio. The fibers will be made of Teflon AF, a clear, amorphous, low-refractive-index fluoropolymer. When filled with nearly any transparent liquid (including water), they will act as optical fibers, capturing and confining both excitation and Raman scattered radiation over large interaction lengths. In doing so, they will greatly increase signal intensity relative to conventional sampling arrangements. This will enable significant cost reductions through the use of inexpensive low power lasers and/or lower cost detectors as well as reduced acquisition times. This program will extend Phase I work by improving fibers and optimizing the fiber/spectrometer interface. Program goals include demonstrating significant intensity enhancement in aqueous solutions and producing prototypes for specific applications. This project will ease the performance requirements of lasers and detectors and result in the production of Raman laboratory instruments (for undergraduate teaching and biological sampling) and low cost, compact, reliable and robust test cells.