掺铥钼酸钆钡晶体1.9μm腔面膜的研制

Design and fabrication of cavity surface coatings on the Tm^(3+)∶BaGd_2(MoO_4)_4 crystal for 1.9 μm laser emission

根据Tm^(3+)∶BaGd_2(MoO_4)_4激光晶体的发光特性,以厚度为1.1 mm的该晶体为基底,选择Ta_2O_5和SiO_2作为高低折射率膜料,通过电子枪蒸镀的物理沉积方式分别在晶体两端面设计并镀制了输入膜系和输出膜系,同时采用霍尔离子源辅助沉积来增强晶体与膜层之间的结合力。镀膜后的晶体输入端面795 nm透过率大于90%,1.9μm透过率小于0.2%;输出端面795 nm透过率小于10%,1.9μm透过率等于6.55%。通过采用795 nm波长的半导体激光泵浦镀膜后的晶体,实现了1.9μm准连续激光输出,结果表明该激光输入输出膜系的镀制满足激光器实验的使用要求。

According to the luminescence properties of Tm^3＋∶BaGd2（MoO4）4 laser crystal,choosing Ta2O5 and SiO2 as high and low refractive index materials,the cavity surface coatings are prepared on the Tm^3＋∶BaGd2（MoO4）4 crystal with thickness of 1.1mm by electron-beam evaporation system,and Hall ion source assisted deposition is used to enhance the bonding force between the crystal and the coatings. On the incident surface of the crystal after coating film,the transmittance is above 90% at 795 nm wavelength,and the transmittance is less than 0. 2% at 1900 nm. The transmittance of the opposite surface is less than 10% at 795 nm,and the transmittance is 6. 55% at 1900 nm. Using a coated crystal as the gain medium and a fiber-coupled 795 nm diode laser as the pumping source,the quasi-CW1. 9 μm laser operation is realized. The test results show that the cavity surface coatings meet the requirements of the laser experiment.