N. A. Wright, R. A. Crocombe and D. L. Drapcho

Bio-Rad, Digilab Division

237 Putnam Avenue

Cambridge, MA 02139 U.S.A.

An infrared spectroscopic imaging technique has been developed which combines a step-scan Fourier transform (FT) Michelson interferometer with focal plane array (FPA) image detection. The first reports utilized an indium antimonide (InSb) FPA in the spectral region 3950-1975 cm^-1. Mercury-cadmium-telluride (MCT) focal plane arrays are now commercially available, giving access to the spectral range 3950-800 cm^-1, thus greatly broadening the application of the technique for chemical analysis in the mid infrared region. This paper describes some of the instrumental considerations as well as applications in the use of an MCT array detector, for novel mid-infrared spectroscopic imaging applications.

Imaging Spectroscopic analysis is an emerging new technique that provides chemical specific infrared images. With the analytical resolution achieved using an interferometer, specific chemical information becomes available. Slight band shifts can now be routinely detected and used as an aid in complex problem solving. From the images precise information about the chemical composition and material structure of a sample is obtained. This type of information is significant as it allows the investigator to understand more fully a chemically diverse sample, which is the rule rather than the exception, when studying either made-made or naturally occurring materials. Due to the ease of infrared image generation, and the power of image analysis software tools, the ability to study complex systems is now readily available so that the analysis and applications become the focus rather than the experimental technique itself.