title: Performance of a high-resolution mid-IR optical-parametric-oscillator transient absorption spectrometer.
abstract: We report on a mid-IR optical parametric oscillator (OPO)-based high resolution transient absorption spectrometer for state-resolved collisional energy transfer. Transient Doppler-broadened line profiles at λ = 3.3 μm are reported for HCl R7 transitions following gas-phase collisions with vibrationally excited pyrazine. The instrument noise, analyzed as a function of IR wavelength across the absorption line, is as much as 10 times smaller than in diode laser-based measurements. The reduced noise is attributed to larger intensity IR light that has greater intensity stability, which in turn leads to reduced detector noise and better frequency locking for the OPO.
authors: Geraldine O
authors: GO
authors: Echebiri
authors: Matthew D
authors: MD
authors: Smarte
authors: Wendell W
authors: WW
authors: Walters
authors: Amy S
authors: AS
authors: Mullin