[1] Zhu J Q, Zhu H, Xu H L, et al. Ge-based mid-infrared blocked-impurity-band photodetectors [J]. Infrared Physics & Technology, 2018, 92: 13-17.
[2] Woyessa G, Kwarkye K, Dasa M K, et al. Power stable 1.5-10.5 µm cascaded mid-infrared supercontinuum laser without thulium amplifier [J]. Optics Letters, 2021, 46(5): 1129-1132. doi:  10.1364/OL.416123
[3] Wu T, Kong W P, Wang M Y, et al. Compact hollow waveguide mid-infrared gas sensor for simultaneous measurements of ambient CO2 and water vapor [J]. Journal of Lightwave Technology, 2020, 38(16): 4580-4587. doi:  10.1109/JLT.2020.2990977
[4] Pi M Q, Zheng C T, Zhao H, et al. Mid-infrared CHG-on-MgF2 waveguide gas sensor based on wavelength modulation spectroscopy [J]. Optics Letters, 2021, 46(21): 4797-4800.
[5] Dodge M J. Refractive properties of magnesium fluoride [J]. Applied Optics, 1984, 23(12): 1980-1985. doi:  10.1364/AO.23.001980
[6] Murphy E J. Integrated optical circuits and components: design and applications [M]. Boca Raton: CRC Press, 1999.
[7] McNab S J, Moll N, Vlasov Y A. Ultra-low loss photonic integrated circuit with membrane-type photonic crystal waveguides [J]. Optics Express, 2003, 11(22): 2927-2939. doi:  10.1364/OE.11.002927
[8] Jia Y C, Wang S X, Chen F. Femtosecond laser direct writing of flexibly configured waveguide geometries in optical crystals: fabrication and application [J]. Opto-Electronic Advances, 2020, 3(10): 190042. doi:  10.29026/oea.2020.190042
[9] Jia Y C, Wang L, Chen F. Ion-cut lithium niobate on insulator technology: Recent advances and perspectives [J]. Applied Physics Reviews, 2021, 8: 011307. doi:  10.1063/5.0037771
[10] Yang Q X, Liu H L, He S, et al. Circular cladding waveguides in Pr: YAG fabricated by femtosecond laser inscription: Raman, luminescence properties and guiding performance [J]. Opto-Electronic Advances, 2021, 4(2): 200005. doi:  10.29026/oea.2021.200005
[11] Liu T, Yao Y C, Liu F R, et al. Enhanced Raman intensity in ZnS planar and channel waveguide structures via carbon ion implantation [J]. Optical Materials, 2021, 112: 110733. doi:  10.1016/j.optmat.2020.110733
[12] Li R, Sun L F, Cai Y J, et al. Near-infrared lasing and tunable upconversion from femtosecond laser inscribed Nd, Gd: CaF2 waveguides [J]. Chinese Optics Letters, 2021, 19(8): 081301. doi:  10.3788/COL202119.081301
[13] Li R, Nie W J, Lu Q M, et al. Femtosecond-laser-written superficial cladding waveguides in Nd: CaF2 crystal [J]. Optics & Laser Technology, 2017, 92(1): 163-167.
[14] Zhang L M, Guo T Y, Ren Y Y, et al. Cooperative up-converted luminescence in Yb, Na: CaF2 cladding waveguides by femtosecond laser inscription [J]. Optics Communications, 2019, 441(15): 8-13.
[15] Jia Y C, Chen F, Vazquez de Aldana J R, et al. Femtosecond laser micromachining of Nd: GdCOB ridge waveguides for second harmonic generation [J]. Optical Materials, 2012, 34(11): 1913-1916. doi:  10.1016/j.optmat.2012.05.032
[16] Jia Y C, Dong N N, Chen F, et al. Continuous wave ridge waveguide lasers in femtosecond laser micromachined ion irradiated Nd: YAG single crystals [J]. Optical Materials Express, 2012, 2(5): 657-662. doi:  10.1364/OME.2.000657
[17] Tan Y, Luan Q F, Liu F Q, et al. Swift carbon ion irradiated Nd: YAG ceramic optical waveguide amplifier [J]. Optics Express, 2013, 21(12): 13992-13997. doi:  10.1364/OE.21.013992
[18] Siebenmorgen J, Petermann K, Huber G, et al. Femtosecond laser written stress-induced Nd: Y3Al5O12 (Nd: YAG) channel waveguide laser [J]. Applied Physics B, 2009, 97: 251-255. doi:  10.1007/s00340-009-3697-3