Abstract

Vibrational sum-frequency spectroscopy (VSFS) has been used for some time as a laboratory-based surface chemical analytical tool. Here, theoretical considerations in applying the method as a remote-sensing probe for detecting trace levels of chemicals adsorbed on surfaces are presented. Additionally, a VSFS instrument is configured to operate at a stand-off distance of 2.2 m using near-nadir incidence angles. This system was used to measure VSFS spectra for films of pure 1-amino-4-nitrobenzene (<i>p</i>-nitroaniline, PNA) and pure 2-hydroxy-1,3,5-trinitrobenzene (picric acid, PA) adsorbed on polished T-6061 aluminum alloy. These spectra are used to investigate the effect of optical polarization on the sum-frequency response of these compounds at nadir optical geometries. Detection limits for each compound are also estimated and found to be 0.51 μg cm² for PNA and 0.89 μg cm² for PA. The implications of these results regarding remote sensing applications of VSFS are discussed.

Fourier-transform sum-frequency surface vibrational spectroscopy with femtosecond pulses

J. A. McGuire, W. Beck, X. Wei, and Y. R. Shen
Opt. Lett. 24(24) 1877-1879 (1999)

Signal and noise in Fourier-transform sum-frequency surface vibrational spectroscopy with femtosecond lasers

John A. McGuire and Y. R. Shen
J. Opt. Soc. Am. B 23(2) 363-369 (2006)

Stand-off detection of explosives particles by multispectral imaging Raman spectroscopy

Henric Östmark, Markus Nordberg, and Torgny E. Carlsson
Appl. Opt. 50(28) 5592-5599 (2011)

Multiplex coherent anti-Stokes Raman scattering spectroscopy for trace chemical detection

Sherrie B. Pilkington, Stephen D. Roberson, and Paul M. Pellegrino
Appl. Opt. 56(3) B159-B168 (2017)

Vibrational sum frequency generation spectroscopy using inverted visible pulses

Champika Weeraman, Steven A. Mitchell, Rune Lausten, Linda J. Johnston, and Albert Stolow
Opt. Express 18(11) 11483-11494 (2010)