We report on a widely tunable continuous-wave single-frequency pump-resonant signal-resonant optical parametric oscillator (PRSRO) delivering 20 mW to 50 mW of idler power spanning an octave bandwidth in the mid-infrared (1.7 µm–3.5 µm). This PRSRO is pumped by a continuous-wave Ti:Al2O3 single-frequency and tunable laser delivering 760 mW around 795 nm, and thanks to the pump enhancement a threshold as low as 110 mW is achieved. This nonlinear laser source which is widely tunable in the mid-IR spectral range is part of the radiometric laser chain project aimed at the calibration of the spectral responsivity of photo-detectors in the UV-IR range by spectral irradiance measurement via a cryogenic radiometer. This widely tunable source is also suited to high-resolution molecular spectroscopy in the mid-infrared range.

Key words

nonlinear optics
optical parametric oscillator
parametric interactions
tunable laser