Three-wavelength green generation in Nd:GdCOB slab crystal based on self-frequency conversion

We report on a multi-self-frequency conversion in one Nd3+-doped GdCa4O(BO3)3 (Nd:GdCOB) slab crystal, including self-sum-frequency (SSF) at 538 nm and self-frequency doubling (SFD) at 530 and 545 nm from two fundamental infrared wavelengths at 1060 and 1091 nm for the first time. The total output power of the three green lasers was up to 1.7 W with a 0.9 W SSF output at 538 nm. To our knowledge, this is the highest total green output power and the highest SSF power at 538 nm via the multi-self-frequency conversion process in SFD crystal. Moreover, a theoretical simulation of the temperature distribution in the slab by considering the pump power induced thermal effect was implemented, leading a deep insight into the physical mechanism of multi-wavelength generation.