激光晶体YAG中Er^(3+)的辐射跃迁

RADIATIVE TRANSITIOTS OF YAG:Er LASER CRYSTALS

本文讨论和分析了激光晶体YAG中Er^(3+)离子的激光上能级的~4S_(3/2)、~4I_(11/2)和~4I_(13/2)辐射跃迁的有关因素。

YAG: Er laser crystals were grown by Czochralski technique with Er3+ ion concentrations of 1.635×1021/cm3, 1.156 ×1021/cm3, 0.044×1021/cm8 and 0.029×1021/cm3 respectively. The spectral properties of YAG:Er3 + crystals were studied and the absorption cross sections were obtained. It is noted that YAG:Er3+ laser is optically pumped because there is absorption exsting in ultraviolet, visible and near infrared ranges. The energy gaps between some pairs of Er3 + levels in the YAG:Er3+ coincide each other,which can cause the cross relaxation process.By analysing the spectra of YAG:Er3+ crystal, the actions of radiative transition from 4S3/2, 4I9/2,4I11/2 and 4I13/2 to 4I15/2 levels are discussed.The cross relaxation process between certain pairs of Er3+ levels in YAG:Er3+ is a nonradiative process under multipole interaction, in which dipole-dipole interactions are considered to play a dominant role. The fluorescence of 4I9/2 and 4S3/2 levels is quenched with the increase of Er3+ concentration, and that of 4I11/2 level presents an increase. For 4S3/2, 4I9/2 and 4I13/2 there is an optimum concentration.