<title>Very fast imaging FT spectrometer for online process monitoring and control</title>

Abstract

Designs & Prototypes has developed a small, very fast, rugged rotary Fourier transform (FT) spectrometer, which can be used in conjunction with fiber optics to monitor industrial processes. When used in an imaging configuration with a mosaic detector array, multiple processes (or multiple locations in a process) can be monitored simultaneously. The rotary scan allows operation without the laser reference of conventional FT spectrometers, and can easily yield scan rates from 30 to more than 300 scans per second. Single pixel operation at 360 scans per second and 1 cm -1 resolution, with excellent lineshape, has been demonstrated. Multiple pixel operation has also been demonstrated using a 3X3 HgCdTe PC mosaic detector. Field testing of a hand portable version with 8 cm-1 resolution will be performed in late summer 1998. The unit can measure spectra in the NIR, SWIR, and Thermal IR, with the appropriate optics and detector sets. The optical bench for 8 cm-1 resolution is 2.5X3.5 inches, and 2.5 inches high. It weighs 11.5 oz., and is totally sealed from the environment. Electrons for servo and detector channel functions can be packaged into an enclosure 6X4X2 inches. For very fast real time processing, single or multiple DSPs can be used. The development work has been supported by contracts from the U.S. Army, a large U.S. aerospace company, and a major Australian mining company.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.