Spectroscopic characterization of narrowband output from injection-seeded pulsed optical parametric oscillators

Pulsed optical parametric oscillators (OPOs) are versatile nonlinear-optical (NLO) sources of tunable coherent light for spectroscopic sensing applications. One of our most recent demonstrations of such OPO wavelength control strategies is a novel self-adaptive tunable (SAT) design, in which a photorefractive crystal serves as a phase-conjugate cavity mirror and enables SLM tuning without active variation of OPO cavity length as the TDL seed wavelength λ_seed is scanned. We now report further details of the performance of such a SAT OPO, including narrowband spectroscopic characteristics of its idler output at λ_idler, via cavity ringdown absorption spectra of CO₂(g) at ∼1.44 μm, and of its seeded signal output at λ_signal, by recording fluorescence-detected Doppler-free two-photon absorption (TPA) spectra of Cs(g) at ∼822 nm.