报道了低功率激光二极管(LD)抽运的1030 nm Yb:YAG全固态激光器。由于Yb:YAG为准三能级结构,自吸收损耗大,振荡阈值高,因此采用双路偏振耦合系统增加注入功率密度,并通过降低晶体掺杂浓度,选取合适晶体厚度,用半导体制冷器(TEC)有效制冷,在线性腔中实现了1030 nm波长稳定输出。Yb:YAG晶体Yb离子掺杂原子数分数为8%,几何尺寸为11 mm×0.7 mm,晶体面对输出镜一端镀940 nm高反膜,使未被吸收的抽运光反射回去,再次抽运晶体,从而提高了抽运光的利用效率,当注入功率为2 W时,1030 nm输出功率为192.8 mW,光-光转换效率为9.6%,2 h内稳定度小于3.5%。

A low power laser diode (LD) end-pumped Yb:YAG laser has been demonstrated. At room temperature, the Yb:YAG laser has a quasi-three-level structure; and the lasing threshold is high because of serious re-absorption at the laser wavelength. In order to improve pump intensity, double LD polarization coupling system was employed in the experiment. The stable operation at 1030 nm was realized in a linear cavity by reducing doping concentration and efficient cooling with thermal electric cooler (TEC). The crystal is 0.7 mm in thickness and 11mm in diameter. The doping concentration (atomic percent) is 8%. The end face of crystal is coated for high reflection at 940 nm, which leads to a second pass of the pump light. The maximum output power of 192.8 mW at 1030 nm is obtained when the incident power is 2 W. The optical-optical conversion efficiency is 9.6%. The power instability is better than ±3.5% in 2 hours.