title: Raman linewidth measurements using time-resolved hybrid picosecond/nanosecond rotational CARS.
abstract: We report an innovative approach for time-domain measurements of S-branch Raman linewidths using hybrid picosecond/nanosecond pure-rotational coherent anti-Stokes Raman spectroscopy (RCARS). The Raman coherences are created by two picosecond excitation pulses and are probed using a narrow-band nanosecond pulse at 532 nm. The generated RCARS signal contains the entire coherence decay in a single pulse. By extracting the decay times of the individual transitions, the J-dependent Raman linewidths can be calculated. Self-broadened S-branch linewidths for nitrogen and oxygen at 293 K and ambient pressure are in good agreement with previous time-domain measurements. Experimental considerations of the approach are discussed along with its merits and limitations. The approach can be extended to a wide range of pressures and temperatures and has potential for simultaneous single-shot thermometry and linewidth determination.
authors.forename: Emil
authors.initials: E
authors.lastname: Nordström
authors.forename: Ali
authors.initials: A
authors.lastname: Hosseinnia
authors.forename: Christian
authors.initials: C
authors.lastname: Brackmann
authors.forename: Joakim
authors.initials: J
authors.lastname: Bood
authors.forename: Per-Erik
authors.initials: PE
authors.lastname: Bengtsson