[1] Fried N M. Recent advances in infrared laser lithotripsy [Invited][J]. Biomedical Optics Express, 9, 4552-4568(2018).

[2] Henderson S W, Suni P J M, Hale C P, et al. Coherent laser radar at 2 μm using solid-state lasers[J]. IEEE Transactions on Geoscience and Remote Sensing, 31, 4-15(1993).

[3] Targ R, Steakley B C, Hawley J G, et al. Coherent lidar airborne wind sensor II: flight-test results at 2 and 10 μm[J]. Applied Optics, 35, 7117-7127(1996).

[4] Leindecker N, Marandi A, Byer R L, et al. Octave-spanning ultrafast OPO with 2.6-6.1µm instantaneous bandwidth pumped by femtosecond Tm-fiber laser[J]. Optics Express, 20, 7046-7053(2012).

[5] Lippert E, Fonnum H, Arisholm G, et al. A 22-watt mid-infrared optical parametric oscillator with V-shaped 3-mirror ring resonator[J]. Optics Express, 18, 26475-26483(2010).

[6] Jin Lin, Liu Pian, Huang Haitao, et al. High average power of Q-switched Tm: YAG slab laser[J]. Optics Communications, 372, 241-244(2016).

[7] Kwiatkowski J. Power and spectral analyses in diode-pumped c-cut Pbnm Tm: YAP laser[J]. Chinese Optics Letters, 18, 091401(2020).

[8] Na Quanxin, Xu Changwen, Huang Zhiyang, et al. High-power and high-efficiency short wavelength operation of a Tm: YLF laser at 1.83 μm[J]. Optics Letters, 44, 4403-4406(2019).

[9] Li Shutao, Niu C, Wen Y, et al. Laser characteristics of LD end-pumped CW and Q-switched Tm: LuYAG laser[J]. Infrared Physics & Technology, 111, 103559(2020).

[10] Sottile A, Damiano E, Rabe M, et al. Widely tunable, efficient 2 µm laser in monocrystalline Tm³⁺: SrF₂[J]. Optics Express, 26, 5368-5380(2018).

[11] Berthomé Q, Grisard A, Faure B, et al. Actively Q-switched tunable single-longitudinal-mode 2 µm Tm: YAP laser using a transversally chirped volume Bragg grating[J]. Optics Express, 28, 5013-5021(2020).

[12] Liu Jian, Dong Jifei, Wang Yinyin, et al. Tm: YAG single-crystal fiber laser[J]. Optics Letters, 46, 4454-4457(2021).

[13] Shaw L B, Chang R S F, Djeu N. Measurement of up-conversion energy-transfer probabilities in Ho: Y₃A1₅O₁₂ and Tm: Y₃A1₅O₁₂[J]. Physical Review B, 50, 6609-6619(1994).

[14] Zhang Zhen, Guo Xinsheng, Wang Jingya, et al. High-efficiency 2 μm continuous-wave laser in laser diode-pumped Tm³⁺, La³⁺: CaF₂ single crystal[J]. Optics Letters, 43, 4300-4303(2018).

[15] Ma Fengkai, Su Fang, Zhou Rongfu, et al. The defect aggregation of RE³⁺ (RE = Y, La ～ Lu) in MF₂ (M = Ca, Sr, Ba) fluorites[J]. Materials Research Bulletin, 125, 110788(2020).

[16] Doualan J L, Camy P, Moncorgé R, et al. Latest developments of bulk crystals and thin films of rare-earth doped CaF₂ for laser applications[J]. Journal of Fluorine Chemistry, 128, 459-464(2007).

[17] Liu Jingjing, Zhang Cheng, Zhang Zhen, et al. 1886-nm mode-locked and wavelength tunable Tm-doped CaF₂ lasers[J]. Optics Letters, 44, 134-137(2019).

[18] Wang Yangxiao, Liu Wenxin, Zhang Zhonghan, et al. Laser-diode-pumped Tm: SrF₂ single crystal for high efficiency CW laser operation at ～2 µm[J]. Optics Letters, 47, 1117-1120(2022).

[19] Liu Wenxin, Zu Yuqian, Wang Yangxiao, et al. Active Q-switching operation of a Tm: SrF₂ single crystal fiber laser near 2 µm[J]. Optical Materials Express, 11, 2877-2882(2021).

[20] Ma Weiwei, Qian Xiaobo, Wang Jingya, et al. Highly efficient dual-wavelength mid-infrared CW Laser in diode end-pumped Er: SrF₂ single crystals[J]. Scientific Reports, 6, 36635(2016).

[21] Camy P, Doualan J L, Renard S, et al. Tm ³⁺: CaF₂ for 1.9 μm laser operation[J]. Optics Communications, 236, 395-402(2004).

[22] Degnan J J. Theory of the optimally coupled Q-switched laser[J]. IEEE Journal of Quantum Electronics, 25, 214-220(1989).