Abstract: 2 μm laser is one of the most important eye-safe lasers, and has important potential and practical applications in military and civilian fields such as medical treatment, materials processing, infrared detection/IR-counter measurement, and atmospheric environment monitoring. Due to their broad absorption and emission band in 2 μm range, high thermal conductivity, and low phonon energy, Ho³⁺ doped sesquioxide ceramic materials are important type of 2 μm laser materials. In addition, through forming the solid solution, much wider absorption and emission band can even be achieved, which give them the possibility to be the excellent mid-infrared solid-state laser materials. In this work, vacuum pressureless sintering combined with hot isostatic pressing sintering treatment was applied to prepare the 0.5%Ho∶(Y_0.7Sc_0.3)₂O₃ transparent ceramics by using commercial available Y₂O₃, Sc₂O₃ and Ho₂O₃ powders as the starting materials. By adding ZrO₂ as the sintering aid, grain growth of the Ho∶(Y_0.7Sc_0.3)₂O₃ ceramic at high sintering temperature was effectively inhibited. The effect of ZrO₂ doping ranged from 0~1.0% on the densification process, its further effect on the optical properties of Ho∶(Y_0.7Sc_0.3)₂O₃ laser ceramics was studied thoroughly. After pre-sintered at 1 690 ℃ for 4 h in vacuum and then hot isostatic sintered at 1 600 ℃/190 MPa for 3 h, the transmittance of 1.0%ZrO₂ doped Ho∶(Y_0.7Sc_0.3)₂O₃ ceramic reaches 79.1% at 1 100 nm (4.4 mm in thickness), which is close to its theoretic value.

Key words: Ho∶(Y_0.7Sc_0.3)₂O₃, laser ceramics, optical property, ZrO₂, hot isostatic pressing