Rovibrational hybrid fs/ps CARS using a volume Bragg grating for N₂ thermometry.

Coherent anti-Stokes Raman scattering (CARS) spectra of N2 in the hybrid femtosecond/ picosecondregime have been recorded with 0.7  cm−1 resolution. The Q-branch rovibrational structure has been resolved, making it suitable for gas-phase simultaneous rotational and vibrational thermometry applications. Resolving this spectral structure requires synchronization of a narrowband picosecondprobe pulse with a broadband femtosecondpair of pump and Stokes pulses. It is achieved using a single femtosecond ytterbium-laser source and a volume Bragg grating in a compact experimental arrangement.