Rapidly tunable intra-cavity Cr3+:LiCAF-PPSLT optical parametric oscillator based on a self-injection-locked pump wave

We present a doubly resonant intra-cavity pumped OPO consisting of a Cr³⁺:LiCAF tunable laser and a periodically poled stoichiometric lithium tantalate (PPSLT) nonlinear crystal. Laser tuning is achieved through self-injection-locking with an externally coupled cavity based on a Littrow-mounted ruled diffraction grating. This allows for faster OPO tuning by piezo tilting or dithering the grating as compared with standard temperature tuning, and narrows the laser (OPO pump) linewidth. The laser crystal was a-cut for polarized oscillation (as required for efficient quasi-phase matching and for photomixing).