Laser-diode end-pumped electro-optic Q-switched Tm:SrF2 laser
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摘要: 高掺杂浓度的Tm3+增益介质能通过交叉弛豫过程提高激光器的量子效率,但同时也会增加能量上转换带来的损耗,从而限制激光器效率的进一步提升。对Tm:SrF2晶体的荧光特性以及激光性能展开研究。在激光二极管(LD)端面泵浦下,实现最大功率2.99 W的自由运转输出,激光器的泵浦阈值为0.89 W,中心波长1851 nm,斜效率高达82.1%。采用KTP电光调Q开关演示了Tm:SrF2激光器的电光调Q输出特性。在500 Hz重复频率下,获得了1.02 mJ的最大单脉冲能量,泵浦阈值为2.01 W,最短脉冲宽度为45 ns,对应峰值功率为22.67 kW。实验结果表明,基于LD泵浦的Tm:SrF2激光器具有非常高的效率,有望成为中红外光学参量振荡器(OPO)和光学参量放大器(OPA)的理想泵浦源。
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关键词:
- 激光技术 /
- Tm:SrF2激光器 /
- 电光调Q /
- LD端面泵浦 /
- 斜效率
Abstract: The Tm3+ gain medium with high doping concentration can improve the quantum efficiency of the laser through the cross relaxation process, but it also increases the energy loss caused by energy up-conversion and limits the improvement of laser efficiency. The fluorescence characteristics and laser performance of Tm:SrF2 crystal are studied. Under laser-diode (LD) end-pumping, a continuous-wave laser with a maximum output power of 2.99 W and a slope efficiency of up to 82.1% is realized. The pump threshold of the laser is 0.81 W, and the center wavelength is 1851 nm. Electro-optic Q-switching of the Tm:SrF2 laser is demonstrated. At the repetition rate of 500 Hz, a maximum pulse energy of 1.02 mJ and a minimum pulse width of 45 ns are achieved, resulting in a peak power of 22.67 kW. The experimental results indicate that the Tm:SrF2 laser based on LD pumping has very high efficiency and is expected to be an ideal pump source for optical parametric oscillators (OPOs) and optical parametric amplifiers (OPAs).-
Key words:
- laser technology /
- Tm:SrF2 laser /
- electro-optical Q-switching /
- LD end-pump /
- slope efficiency
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表 1 掺Tm块状晶体的激光性能
Table 1. Laser performance of Tm-doped bulk crystals
material doping concentration/% output power/W slope efficiency/% photon quantum efficiency reference Tm:YAG 3.5 25.40 41.2 1.05 [6] Tm:YAP 3.0 6.35 60.4 1.51 [7] Tm:YLF 2.5 8.50 53.4 1.23 [8] Tm:LuAG 3.5 3.70 54.6 1.39 [9] Tm:SrF2 5.2 0.24 50.0 1.28 [10] Tm:CaF2 3.0 2.71 70.3 1.68 [18] Tm:SrF2 2.0 2.99 82.1 1.92 this paper -
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