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Presenter: Dr. Chris Manning - Manning Applied Technology, Troy, Idaho
Supervisor:

Date: Wed, November 21, 2001
Time: 13:00:00 - 14:00:00
Place: EOW 430

ABSTRACT

Abstract

Fourier transform-infrared (FT-IR) spectrometry provides a powerful tool for chemical evaluation of a variety of substances, including air and gases, water, food and tissue. Over the past 40 years, the field has matured as instrumentation and signal processing capabilities have improved dramatically. Recently, new approaches to data acquisition have allowed less expensive components to provide better performance. These approaches are computationally intensive, but shift the manufacturing burden from high quality optical hardware toward computer software and hardware. As the price of computer and digital signal processing hardware drops, this tradeoff becomes ever more attractive. In recent years, Manning Applied Technology has been involved in the development of two new interferometers for Specialized applications. Both use rotating optical elements that lead to a sinusoidal variation of optical path difference with time. Consequently, the new approaches to data acquisition and processing are particularly useful. Three related areas of signal processing will be discussed. First is the processing of interferometric data, acquired at equal intervals of time, but uneven intervals of optical path difference, to infrared spectra. Second is the use of adaptive filters to identify and invert detector and preamplifier transfer functions. The third area is application of fixed Fabry-Perot etalons as inexpensive distance standards to stabilize diode lasers to part-per-million wavelength accuracy. A stable diode laser is a very attractive replacement for the helium-neon lasers traditionally used as wavelength standards in FT-IR spectrometers.

Biography

Christopher Manning served in the United States Coast Guard as an avionics electronic technician before studying chemistry and pre-engineering at Framingham State College in Massachusetts. His graduate work with Richard Palmer in the Chemistry Department of Duke University applied step-scan Fourier transform infrared (FT-IR) spectrometry to photoacoustic and photothermal measurements, time-resolved spectroscopy and rheo-optical measurements of polymer films. After the 1991 completion of his doctoral work, he worked with Peter Griffiths at the University of Idaho pioneering the digital control of step-scan interferometers and digital signal processing of interferometric data. Subsequently, he founded Manning Applied Technology and has developed several devices for rheo-optical measurements of polymer films, as well as two novel very-rapid-scan Interferometer designs. Several patents have been issued for these innovations.

FREE AND OPEN TO THE PUBLIC
For Further Information Contact:
Dr. R. Lynn Kirlin (721 8681)