Thermal dephasing compensation in high-power and high-repetition-rate second-harmonic generation using spillover loss

In this paper, the effect of thermal dephasing on the efficiency of a high-power and high-repetition-rate single-pass second-harmonic generation (SHG) in the nanosecond regime is studied. We found that inside a thermal loaded crystal, in addition to the optimization of the focusing parameter and oven temperature, spillover loss can also play a controlling role in retaining the SHG efficiency. It is shown that with a proper choice of the focusing parameter and oven temperature, at about 20 W of averaged fundamental power, at least 60% SHG efficiency is achievable. Moreover, exceeding a certain limit of input power up to 80 W, inducing a spillover loss of about 10%, will help to maintain the SHG efficiency at a maximum value of about 50%.