title: Stand-off detection of solid targets with diffuse reflection spectroscopy using a high-power mid-infrared supercontinuum source.
abstract: We measure the diffuse reflection spectrum of solid samples such as explosives (TNT, RDX, PETN), fertilizers (ammonium nitrate, urea), and paints (automotive and military grade) at a stand-off distance of 5 m using a mid-infrared supercontinuum light source with 3.9 W average output power. The output spectrum extends from 750-4300 nm, and it is generated by nonlinear spectral broadening in a 9 m long fluoride fiber pumped by high peak power pulses from a dual-stage erbium-ytterbium fiber amplifier operating at 1543 nm. The samples are distinguished using unique spectral signatures that are attributed to the molecular vibrations of the constituents. Signal-to-noise ratio (SNR) calculations demonstrate the feasibility of increasing the stand-off distance from 5 to ~150 m, with a corresponding drop in SNR from 28 to 10 dB.
authors.affiliation: Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109, USA. malayk@umich.edu
authors.forename: Malay
authors.initials: M
authors.lastname: Kumar
authors.forename: Mohammed N
authors.initials: MN
authors.lastname: Islam
authors.forename: Fred L
authors.initials: FL
authors.lastname: Terry
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Freeman
authors.forename: Allan
authors.initials: A
authors.lastname: Chan
authors.forename: Manickam
authors.initials: M
authors.lastname: Neelakandan
authors.forename: Tariq
authors.initials: T
authors.lastname: Manzur