激光二极管双端面抽运Tm:Ho:GdVO4 2 μm激光器

报道了激光二极管(LD)双端面抽运Tm∶Ho∶GdVO4固体激光器,在2.049μm处获得连续(CW)和准连续(QCW)激光输出。激光二极管为光纤耦合输出,光纤芯径400μm,数值孔径0.22,输出波长805 nm。激光二极管额定输出功率27.7 W,均分为两束双端面抽运激光晶体。晶体尺寸为4 mm×4 mm×7 mm,Tm,Ho掺杂原子数分数分别为5%,0.5%。分析了Tm∶Ho能级系统的主要能级跃迁和能量转换损耗。为提高激光器的输出功率和转换效率,激光晶体采用液氮制冷。在重复频率5 kHz,10 kHz,20 kHz,调Q以及连续运行模式下,获得了9.4~10.1 W的激光输出,光-光转换效率为34%~36%。最大单脉冲能量为1.9 mJ,最大峰值功率为0.13 MW。讨论了抽运光功率和重复频率对激光脉宽的影响。

Tm: Ho: GdVO4 Laser at 2 μm Using Laser-Diode Double-End Pumping

Continuous wave (CW) and quasi continuous wave (QCW) Tm: Ho: GdVO4 solid laser at 2.049 μm using laser-diode (LD) double-end pumping is reported. The fibre-coupled LD emits a maximum power of 27.7 W at 805 nm with a fiber core diameter of 400 μm and a fiber numerical aperture of 0.22. The LD output is divided into two beams with the same power and double-end pumped the laser crystal. The crystal is co-doped with 5% Tm and 0.5% Ho in dimensions 4 mm×4 mm×7 mm. The spectroscopy and energy loss of the Tm: Ho system is analyzed. The crystal is cooled with liquid N2 for improving the output power and extracted efficiency. The output power of 9.4～10.1 W is obtained at 5, 10, 20-kHz Q-switched and CW modes, corresponding to the optical-to-optical efficiency of 34%～36%. Also, the maximal energy per pulse of 1.9 mJ and the maximal peak power of 0.13 MW are obtained. Additionally, both the alteration of the pump power and that of the repetition rate influence the pulse width.