Abstract
We present a stability transfer from an iodine stabilized Nd:YAG laser to the Mgo:PPLN-based optical parametric oscillator (OPO ) system by using the method of optical transfer cavity. The construction of the cavity is using two high reflective flat-concave mirrors and a fused silica spacer, and the length of the spacer is chosen to avoid coincidence of the frequency of the higher-order modes with fundamental modes. The length of the cavity is controlled by an PZT, and is locked to an iodine stabilized Nd:YAG laser. The frequency of the signal beam of our PPLN OPO is then locked to the cavity. With the stabilization, the stability of the signal beam has a large improve and the mode-hop-free tuning range is then limited only to the mode-hop-free tuning range of the pump laser. The optical transfer cavity is planned to be placed in a stainless steel chamber, which is continuously evacuated by a 2 l/s ion pump to suppress the effect of the variation of the surroundings, after the AR window of the chamber is ready. With the whole setup, we expect the frequency drift of the signal beam of OPO will be less than 60 kHz/h, limited by the stability of Nd:YAG laser.