Abstract
We perform a proof-of-principle demonstration of chemically specific standoff gas sensing, in which a coherent stimulated Raman signal is detected in the direction anticollinear to a two-color laser excitation beam traversing the target volume. The proposed geometry is intrinsically free space as it does not involve back-scattering (reflection) of the signal or excitation beams at or behind the target. A beam carrying an intense mid-IR femtosecond (fs) pulse and a parametrically generated picosecond (ps) UV Stokes pulse is fired in the forward direction. A fs filament, produced by the intense mid-IR pulse, emits a backward-propagating narrowband ps laser pulse at the 337 and 357 nm transitions of excited molecular nitrogen, thus supplying a counter-propagating Raman pump pulse. The scheme is linearly sensitive to species concentration and provides both transverse and longitudinal spatial resolution.
© 2015 Optical Society of America
Full Article | PDF ArticleMore Like This
Sergey Mitryukovskiy, Yi Liu, Pengji Ding, Aurélien Houard, and André Mysyrowicz
Opt. Express 22(11) 12750-12759 (2014)
V. Rakesh Kumar and P. Prem Kiran
Opt. Lett. 40(12) 2802-2805 (2015)
P. N. Malevich, D. Kartashov, Z. Pu, S. Ališauskas, A. Pugžlys, A. Baltuška, L. Giniūnas, R. Danielius, A. A. Lanin, A. M. Zheltikov, M. Marangoni, and G. Cerullo
Opt. Express 20(17) 18784-18794 (2012)