Shock Induced Emission from Sapphire in High-Pressure Phase of Rh₂O₃ (II) Structure

A distinct optical emission from the Rh₂O₃ (II) structural sapphire is observed under shock compression of 125, 132, and 143GPa. The emission intensity continuously increases with the thickness of shocked sapphire. The colour temperature is determined to be about 4000K, which is obviously smaller than the reported value of the alpha phase alumina at the pressures below 80GPa. The present results suggest that the structural transformation will cause an
obvious change of optical property in sapphire.