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.

Advances in explosives analysis—part II: photon and neutron methods

“…A dual SWIR and Raman hyperspectral imager on an unmanned ground vehicle was revealed to enhance explosive discrimination by coupling both methods [79]. A supercontinuum extending from 1300-4300 nm was used to measure diffuse reflectance spectra of several HE over a range extending from SWIR to MWIR [80].…”

Broadband and top-flat mid-infrared supercontinuum generation with 3.52 W time-averaged power in a ZBLAN fiber directly pumped by a 2-µm mode-locked fiber laser and amplifier

“…Such light sources can find applications in a lot of important areas, like standoff detection [1], directional countermeasure [2], and medicine [3,4]. For these applications, the magnitude of bandwidth, spectral flatness as well as the level of output power together with efficient power distribution towards the mid-IR are very important factors.…”

“…When mid-IR spectral region is concerned, soft glass fibers, including tellurite [5,6], fluoride [1,[7][8][9][10][11][12] and chalcogenide [13,14] fibers can be adopted as nonlinear media. However, among all soft glass fibers, only heavy metal fluoride fibers, including fluorozirconate (ZBLAN) [15][16][17][18][19] and fluoroindate (InF 3 ) [20,21] are technologically mature to be used for multi Watt level SC generation.…”

Mid-infrared Supercontinuum Generation to ∼4.7 μm in a ZBLAN Fiber Pumped by an Optical Parametric Generator

“…Mid-Infrared (mid-IR) SC laser sources have attracted significant attention mainly owing to applications in areas such as remote sensing [1], stand-off detection of targets [2], directional infrared countermeasures [3], and medicine [4]. To achieve SC generation in the mid-IR spectral region (λ > 2 μm), soft glass fibers including tellurite [5], fluoride [6]- [8], and chalcogenide [9], [10] have been successfully used.…”