Time-resolved two color single-beam CARS employing supercontinuum and femtosecond pulse shaping
ABSTRACT Using femtosecond pulse shaping techniques to coherently control the signal generation, a single-beam approach for truly time-resolved coherent anti-stokes Raman scattering (CARS) spectroscopy is presented and demonstrated with a molecular sample in liquid phase. In our experimental realization, compressed supercontinuum output of a microstructured fiber is actively shaped in phase to provide two delayed pulses of different color for time-resolved pump–probe measurements. As a compact and experimentally robust approach, it greatly facilitates the application of femtosecond time-resolved CARS in microscopy with chemical contrast.
Article: Standoff and arms-length detection of chemicals with single-beam coherent anti-Stokes Raman scattering.[show abstract] [hide abstract]
ABSTRACT: 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 probe the fundamental vibrations that constitute a molecule's fingerprint. Characteristic Raman lines for several chemicals are successfully obtained from arms-length and 12 m standoff distances. The sensitivity and speed of this approach are also demonstrated.Applied Optics 03/2009; 48(4):B17-22. · 1.41 Impact Factor