title: Single-shot thermometry and OH detection via femtosecond fully resonant electronically enhanced CARS (FREE-CARS).
abstract: Femtosecond time-resolved, fully resonant electronically enhanced coherent anti-Stokes Raman scattering (FREE-CARS) spectroscopy, incorporating a two-color excitation scheme, is used to demonstrate selective and sensitive gas-phase detection of the hydroxyl (OH) radical in a reacting flow. Spectral resolution of the emitted FREE-CARS signal allows simultaneous detection of temperature and relative OH mole fraction under single-laser-shot conditions in a laminar ethylene-air flame. By comparison to previously reported OH concentration and temperature measurements, we demonstrate excellent single-shot temperature accuracies (∼2% deviation from adiabatic flame temperature) and precisions (∼2% standard deviation), with simultaneous relative OH concentration measurements that demonstrate high detection sensitivity (100-300 ppm).
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Wrzesinski
authors.forename: Hans U
authors.initials: HU
authors.lastname: Stauffer
authors.forename: Jacob B
authors.initials: JB
authors.lastname: Schmidt
authors.forename: Sukesh
authors.initials: S
authors.lastname: Roy
authors.forename: James R
authors.initials: JR
authors.lastname: Gord