title: Multimode imaging in the thermal infrared for chemical contrast enhancement. Part 1: Methodology.
abstract: We combine a thermal light source with a conventional thermal infrared camera, alternating current (AC) detection methods, and chemical filtering of the infrared (IR) light to generate several imaging modalities in a simple manner. We demonstrate that digital lock-in amplifier techniques can increase the chemical contrast in an active thermal infrared image using both reflectance and thermal re-emission. We show this method is useful for visualizing thin coatings on fabrics that are invisible to the eye. We also take advantage of a "like-detects-like" chemical filtering approach to chemical selectivity for the purpose of chemical identification using a broadband thermal detector.
authors.affiliation: Department of Chemistry and Biochemistry, 631 Sumter Street, University of South Carolina, Columbia, South Carolina 29208, USA.
authors.forename: Heather
authors.initials: H
authors.lastname: Brooke
authors.forename: Megan R
authors.initials: MR
authors.lastname: Baranowski
authors.forename: Jessica N
authors.initials: JN
authors.lastname: McCutcheon
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Morgan
authors.forename: Michael L
authors.initials: ML
authors.lastname: Myrick