Light Amplification due to Population Inversion between the Valence and Outermost-Core Bands

利用UVSOR环的强起伏辐射作为泵浦源，研究了BaF_2的光致发光（184-240 nm）。结果表明，当调整反射镜使其达到最佳准直状态时，发射强度增强，衰减时间变快。这些事实表明，由于价带和最外芯带之间的粒子数反转的光放大的可能性。

Photoluminescence (184-240 nm) of BaF_2 has been investigated with use of an intense undulatory radiation from the UVSOR ring as a pumping source. It is found that the emission intensity is enhanced and the decay time becomes fast when a mirror is adjusted for best collimation. These facts suggest a possibility of the light amplification due to a population inversion between the valence and outermost-core bands.