Multimode imaging in the thermal infrared for chemical contrast enhancement. Part 1: Methodology.
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.
Brooke
Heather
H
Department of Chemistry and Biochemistry, 631 Sumter Street, University of South Carolina, Columbia, South Carolina 29208, USA.
Baranowski
Megan R
MR
McCutcheon
Jessica N
JN
Morgan
Stephen L
SL
Myrick
Michael L
ML