Coherent mode-selective Raman excitation towards standoff detection

Coherent mode-selective Raman excitation towards standoff detection.

We report the detection of characteristic Raman lines for several chemicals using a single-beam coherent anti-Stokes Raman scattering (CARS) technique from a 12 meter standoff distance. Single laser shot spectra are obtained with sufficient signal to noise ratio to allow molecular identification. Background and spectroscopic discrimination are achieved through binary phase pulse shaping for opt...

Standoff and arms-length detection of chemicals with single-beam coherent anti-Stokes Raman scattering.

The detection of chemicals from safe distances is vital in environments with potentially hazardous or explosive threats, where high sensitivity and fast detection speed are needed. Here we demonstrate standoff detection of several solids, liquids, and gases with single-beam coherent anti-Stokes Raman scattering. This approach utilizes a phase coherent ultrabroad-bandwidth femtosecond laser to p...

Standoff explosives trace detection and imaging by selective stimulated Raman scattering

Mode mixing via resonance Raman excitation profiles

Mode mixing plays an essential role in the reorganization of chemical bonds in molecular systems and impurity centers under electronic transition. Up to now there is no practically useful method which allows to determine this important parameter of vibronic interaction. Here a possibility is proposed which bases on the measurement of resonance Raman excitation profiles. The excitation spectrum ...

UV gated Raman spectroscopy for standoff detection of explosives

Real-time detection and identification of explosives at a standoff distance is a major issue in efforts to develop defense against so-called improvised explosive devices (IED). It is recognized that the only method, which is potentially capable to standoff detection of minimal amounts of explosives is laser-based spectroscopy. LDS technique belongs to trace detection, namely to its micro-partic...