Resonance coherent anti-Stokes Raman scattering in nitrogen dioxide using a broadband dye laser

We have applied electronically resonant coherent anti-Stokes Raman scattering (CARS) to the detection of nitrogen dioxide. The resonance CARS spectrum of NO₂ in a sample cell was recorded around a Raman shift of 1500 cm^-1 using a frequency-doubled injection-seeded single-mode Nd:YAG laser and a tunable dye laser. In particular, we demonstrate the use of a broadband Stokes laser to measure resonance CARS spectra of NO₂. Recordings at various pump laser frequencies were made by temperature tuning of the Nd:YAG master laser. The pressure dependence of the signal was also investigated. The resonance CARS results are compared with laser-induced fluorescence measurements. The work shows the high resolution achievable in complex molecular spectra using resonance CARS.