Enhancing the performance of MgO:PPLN-based optical parametric oscillators with variable-temperature wavelength tuning using a 405 nm laser

In this paper, we significantly and comprehensively enhanced the performance of the optical parametric oscillator (OPO) utilizing temperature elevation for precise wavelength adjustment assisted by a 405 nm laser. This approach works because the irradiation of the MgO:PPLN crystal with a 405 nm laser can alleviate the cavity mode mismatch caused by the pyroelectric-induced photorefractive effect in the crystal, thereby improving the performance of the OPO. The linewidths of the signal and idler light have been narrowed, exhibiting a small spectral bandwidth. The beam quality of the signal light has been significantly improved. The root mean square power fluctuation of the idler light has been reduced to below 1%, and the conversion efficiency has also increased to varying degrees. These results indicate a comprehensive enhancement of the OPO performance. This type of OPO, which maintains high robustness after precise wavelength tuning, is expected to find widespread applications in areas such as gas detection, photocatalysis, and communications.