The research of THz optical parametric oscillator based on ZnGeP2 crystal

In this paper, ZnGeP2 (ZGP) crystal was pumped by a dual-band tunable CO2 laser. Based on the theory of nonlinear optical (NLO) frequency effect, a new THz light was generated. Under the conditions of three-frequency collinear nonlinear interaction and type-II phase matching (o+e→o), formulas of phase-matching angle, efficient nonlinear coefficient, the wave vector direction (θ, Φ), walk-off angle and acceptance angle were derived and relevant curves were analyzed with software. In this paper, the schematic diagram of THz generation based on ring cavity optical parametric oscillator (OPO) was designed. Theory analysis showed that the new ring cavity OPO was reasonable and efficient.