Nd/Cr:YAG媒質における蛍光と反転分布形成の理論的解析

摘要

The Nd/Cr:YAG medium is very useful for the flash lamp or sunlight pumped lasers. Theoretical analysis demonstrates that the fluorescence lifetime of the Nd ions depends on the ratio of the population inversion of the Cr and Nd ions. The ratio of population inversion remarkably changes due to such factors as the pumping rate, the pumping time, and the dopant concentration. Therefore measuring the effeectivelifetime ofNd ions is difficult. The benefit of the Cr ions may not appear soon after the start of pumping until short period of the lifetime of the Nd ions. When the medium is pumped by the short pulse at the absorbed wavelength of the Cr ions, the gain peak is delayed from the end edge of the pump light. The energy transfer rate to the Nd ions from the Cr ions is a crucial parameter. We suggest a method for calculating the transfer rate from two kinds of fluorescence.