Recently, a research team from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences successfully grew a high-entropy garnet-structured oxide crystal and achieved enhanced laser performance at the 2.8 μm wavelength band. By introducing a high-entropy design into a garnet crystal system, the team obtained a wide emission band near 2.8 μm and continuous-wave laser output with improved average power and beam quality, demonstrating the material’s strong potential as a high-performance gain medium for mid-infrared ultrashort-pulse lasers.
The results were published in Crystal Growth & Design.
Mid-infrared ultrashort-pulse lasers around 2.8 μm are of great interest for applications such as space communication and planetary exploration. However, existing laser crystals operating in this wavelength range often suffer from narrow emission bandwidths, low efficiency, or insufficient radiation resistance, making it difficult to meet the demands of efficient and stable laser operation in harsh space radiation environments.
In this study, the researchers combined the advantages of garnet-structured oxide crystals with a high-entropy design strategy, breaking through the long-standing challenge of growing high-entropy crystal materials. They successfully synthesized a 30 at.% erbium-doped gadolinium–lutetium–yttrium–scandium–gallium garnet crystal (Er:GdLuYSGG). The synergistic regulation of multiple cations induced lattice distortion, leading to the local field modulation that broadened both the absorption band at 966 nm and the fluorescence emission band near 2.8 μm.
Using a semiconductor laser for end-pumping, the team achieved continuous-wave laser emission at 2.8 μm with an average output power of 1062 mW and beam quality factors of 1.35 and 1.37. Compared with the conventional Er:LuYSGG crystal, the high-entropy Er:GdLuYSGG crystal showed a significant performance enhancement, with the maximum average output power increased by approximately 16.8%.
This study provides important material support for the development of mid-infrared ultrashort-pulse lasers and further advances both fundamental research and practical applications of high-entropy oxide crystal materials.
Summary diagram of high-entropy Er:GdLuYSGG crystal (Image by ZHANG Huili)
