Investigation on shock-induced luminescence of transparent alumina nanocrystalline ceramics

High-density nanocrystalline transparent ceramics of cubic alumina (γ-Al2O3) were fabricated using nanocrystalline γ-Al2O3 powder as the starting material under a temperature–pressure condition of 4.2 GPa and 300 °C. Subsequently, the optical transmission and shock-induced luminescence performance of the as-fabricated transparent ceramics, serving as optical window materials, were characterized under varying shock pressures via plate impact experiments on a two-stage light gas gun. The experimental results show that, in contrast to the optical signal attenuation observed in single-crystal sapphire under shock loading, the γ-Al2O3 nanocrystalline transparent ceramic windows still maintain good optical transparency for 1550 nm wavelength laser within the shock pressure range of approximately 36–96 GPa. Meanwhile, at similar shock pressures, the absolute radiance of the intrinsic shock-induced luminescence from the nanocrystalline γ-Al2O3 transparent ceramics is an order of magnitude lower than that of c-cut single-crystal sapphire. This demonstrates that the nanocrystalline alumina window material possesses superior shock optical transparency and weaker shock-induced luminescence compared to single-crystal sapphire.