Open AccessUse of photoacoustic excitation and laser vibrometry to remotely detect trace explosives
Author(s) -
Charles M. Wynn,
Robert W. Haupt,
John H. Doherty,
Roderick R. Kunz,
Wenyu Bai
Publication year - 2016
Publication title -
applied optics
Language(s) - English
Resource type - Journals
ISSN - 0003-6935
DOI - 10.1364/ao.55.009054
Subject(s) - explosive material , photoablation , laser , laser doppler vibrometer , optics , materials science , photoacoustic spectroscopy , photoacoustic imaging in biomedicine , laser doppler velocimetry , signal (programming language) , photoacoustic effect , explosive detection , doppler effect , physics , laser power scaling , excimer laser , chemistry , computer science , medicine , blood flow , organic chemistry , astronomy , programming language
In this paper, we examine a laser-based approach to remotely initiate, measure, and differentiate acoustic and vibrational emissions from trace quantities of explosive materials against their environment. Using a pulsed ultraviolet laser (266 nm), we induce a significant (>100 Pa) photoacoustic response from small quantities of military-grade explosives. The photoacoustic signal, with frequencies predominantly between 100 and 500 kHz, is detected remotely via a wideband laser Doppler vibrometer. This two-laser system can be used to rapidly detect and discriminate explosives from ordinary background materials, which have significantly weaker photoacoustic response. A 100 ng/cm 2 limit of detection is estimated. Photoablation is proposed as the dominant mechanism for the large photoacoustic signals generated by explosives.