The broad and slowly varying spectral features of liquids and solids require broadband sources in the mid- to long-wave infrared for their detection and identification. We present here a range of measurements made using uniquely tunable femtosecond optical parametric oscillators, which have enabled stand-off Fourier-transform spectroscopy to be implemented across a large part of the spectral fingerprint region. In this way we have achieved active stand-off detection of liquids on surfaces, of powders and of airborne liquid particles in aerosol form. We discuss the optical parametric oscillator technology, the spectroscopy implementations and the detection capabilities and limitations of the techniques.

© (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

D. T. Reid, O. Kara, M. Rutkauskas, and L. Maidment, "Chemical detection using broadband femtosecond optical parametric oscillators in the 6-12-micron spectral fingerprint region," Proc. SPIE 10639, Micro- and Nanotechnology Sensors, Systems, and Applications X, 106392D (Presented at SPIE Defense + Security: April 19, 2018; Published: 14 May 2018); https://doi.org/10.1117/12.2305129.