Gas-phase thermometry using delayed-probe-pulse picosecond coherent anti-Stokes Raman scattering spectra of H2

We report the development and application of a simple theoretical model for extracting temperatures from picosecond-laser-based coherent anti-Stokes Raman scattering (CARS) spectra of H-2 obtained using time-delayed probe pulses. This approach addresses the challenges associated with the effects of rotational-level-dependent decay lifetimes on time-delayed probing for CARS thermometry. A simple procedure is presented for accurate temperature determination based on a Boltzmann distribution using delayed-probe-pulse vibrational CARS spectra of H-2; this procedure requires measurement at only a select handful of probe-pulse delays and requires no assumptions about sample environment. (C) 2010 Optical Society of America