Continuous-wave frequency tripling and quadrupling by simultaneous three-wave mixings in periodically poled crystals: application to a two-step 119–1071-µm frequency bridge

Abstract

We observed cw third-harmonic generation in a periodically poled LiNbO(3) crystal by cascading optimally phase-matched second-harmonic and sum-frequency generation. Other processes, such as fourth-harmonic generation, are allowed by the flexibility of quasi-phase matching. We demonstrate a divide-by-nine (1.19- 10.71-microm) frequency chain that uses only two lasers.