LUMINESCENCE PROPERTIES OF DEFORMED CAO CRYSTALS

In deformed CaO crystals, the predominant optical-absorption band at 270 nm and the corresponding luminescence band at 450 nm have been investigated. The absorption coefficient increases linearly with deformation up to approximately 5% whereas the luminescence intensity saturates earlier. Thermal annealing indicates that appreciable decrease in the absorption begins at approximately 600 K. In contrast, the luminescence intensity diminishes very rapidly at temperatures not much above room temperature. Time-resolved luminescence indicates that the 450-nm band is composed of two bands: a 475-nm band with lifetimes of. < 3 ns and approximately 10 mus, and a 440-nm band with a lifetime of approximately 1 ms at room temperature. In a test for laser action no optical gain was observed in a deformed CaO crystal.