The research team of transparent and optical functional ceramics led by Li Jiang, a researcher from the Shanghai Institute of Ceramics, Chinese Academy of Sciences to make progress in the research of Yb: Lu2O3 laser ceramics.
Research Background
High-power solid-state lasers have been widely used in the fields of defense and military, high-end equipment manufacturing, and scientific research. At present, the most widely used high-power solid-state laser gain media are Nd / Yb-doped laser materials. Compared with Nd-doped laser materials (such as Nd: YAG), the advantages of Yb-doped laser materials include: Yb3 + absorption band is effectively coupled with laser diode (LD), the absorption line width is large; low quantum loss, high theoretical quantum efficiency; Low thermal load caused by no radiation relaxation; no excited state absorption and up-conversion, high light conversion efficiency; long fluorescence lifetime, conducive to energy storage.
Therefore, Yb-doped transparent ceramics are suitable for use as high-power, high-energy solid-state laser gain media. The matrix material determines the physical and chemical properties of the gain medium. For high-power laser matrix materials, high thermal conductivity is one of the most important properties. Lu2O3 has higher thermal conductivity than YAG, but its single crystal melting point is as high as 2490 degrees Celsius. It is difficult to prepare high-quality, large-sized Lu2O3 single crystals in the prior art, but high optical quality Lu2O3 can be obtained at a lower sintering temperature. Transparent ceramic.
Therefore, Lu2O3-based transparent laser ceramics have become very promising candidates. Because the ionic radius and atomic mass of Yb3 + and Lu3 + are very close, the phonon energy of Yb: Lu2O3 is low, and the thermal conductivity has little change with the increase of the doping concentration of Yb3 + (high concentration doping can be achieved); at the same time, the thermal expansion coefficient of Lu2O3 Low, excellent thermal shock resistance, so Yb: Lu2O3 laser ceramics with high optical quality are considered to be a kind of high power solid laser gain medium with great development potential.
Research progress
Using the Yb: Lu2O3 nano-powder prepared by the co-precipitation method as the raw material, the team successfully prepared high-quality Yb: Lu2O3 transparent ceramics by using vacuum pre-firing and hot isostatic post-treatment process. The fiber-coupled laser diode (LD) was used to perform quasi-continuous (QCW) pumping at 929.4nm, achieving a maximum laser power output of 8.15W at 1033.4nm, and the slope efficiency was as high as 58.4%.
Sesquioxide ceramics (Sc2O3, Lu2O3, Y2O3) are very promising high-performance laser gain media due to their high thermal conductivity, good thermomechanical properties, excellent optical properties, and wide-band transparency. The thermal conductivity of Sc2O3 is as high as 17W / m × K, and the ground state of Yb: Sc2O3 material is large. It has a wide emission band and can be tuned with a wide wavelength to achieve ultra-short pulse amplification.
The team used the co-precipitation method to synthesize Yb: Sc2O3 nano-powders with high dispersion and high sintering activity. The vacuum sintering technology was used to obtain high-quality Yb: Sc2O3 transparent ceramics. Fiber-coupled 968nm laser diode (LD) pumped Yb: Sc2O3 ceramics to achieve 2.44W continuous laser output at 1040nm, with a slope efficiency of 35%, and a tunable laser wavelength range of 55nm (J. Eur. Ceram. Soc., 2018, 38: 1632-1638).
Relevant research work has been funded by the Chinese Academy of Sciences Key Research Program of Frontier Science (the Academy's Young Top Talent Project), the National Natural Science Foundation of China, the National Key R & D Program, and the Shanghai Institute of Ceramics Key Discipline Construction Project.
中国科学院上海硅酸盐研究所透明与光功能陶瓷研究团队