Total internal reflection noncollinear quasi-phase-matching PPLN OPO

The refractive index of the periodically poled lithium niobate (PPLN) is about twice as many as the refractive index of the air. When the rotation angle of the periodically poled crystal is bigger, the pump, signal and idler waves can form total internal reflection (TIR) inside the crystal, and the TIR noncollinear quasi-phase-matching (TIR-NQPM) optical parametric oscillator (OPO) can be realized if properly setting the angle of the OPO output coupler synchronously. In this paper, TIR-NQPM OPO based on PPLN pumped with a 1064nm all-solid-state laser is reported for the first time. In our experiment, the angle of rotation for PPLN is 5.57° and 1504-1542 nm of signal wavelength was achieved by tuning the work temperature from 140°C to 250°C. Although adjustment of the cavity is difficult for this method, it broadens the rotation range of angle-tuned QPM OPO. As a result, by one time or more than one time total internal reflections inside the crystal, TIR-NQPM has less limitation of the transverse size of the periodically poled crystal, and the output wavelength range could be increased remarkably.