Time-resolved dynamics of resonant and nonresonant broadband picosecond coherent anti-Stokes Raman scattering signals

Abstract

The time-resolved dynamics of resonant and nonresonant broadband picosecond coherent anti-Stokes Raman scattering (CARS) signals in gas-phase media are investigated. For ∼135ps pump and probe beams and ∼106ps Stokes beams, the magnitude of the nonresonant signals are decreased by more than three orders of magnitude when the probe beam is delayed by ∼110ps, whereas the resonant nitrogen CARS signal is reduced only by a factor of 3. Investigation of these time dynamics is important for understanding the optimal time delay for nonresonant background suppression as well as for understanding the collisional and Doppler dependence of the resonant CARS signals.