ErYLF晶体中Er^（3＋）离子的光谱特征

Spectral Characteristics of Er 3+ Ions in Er∶YLF Crystal

利用居地－奥非脱（Ｊｕｄｄ－Ｏｆｅｌｔ）［２，３］理论计算了Ｅｒ３＋离子在氟化钇锂（ＬｉＹＦ４简写为ＹＬＦ）晶体中的辐射跃迁几率ＡＪＪ′，无辐射跃迁几率ωＪＪ′及激发态荧光寿命τＪ，并根据荧光动力学方程计算出各激发态布居数ＮＪ与掺杂浓度ｘ的关系。对２．７μｍ激光（４Ｉ１１／２→４Ｉ１３／２）来说，掺杂浓度要大于～３ａｔ．％，才能实现布居数反转，对波长为１．７３μｍ的４Ｉ１３／２→４Ｉ１５／２跃迁，存在荧光强度最大的掺杂浓度ｘｏｐ，在泵浦几率为１０３～１０５ｓ－１范围内，ｘｏｐ为１．８～３．０ａｔ．％。文中还计算了ＥｒＹＡＧ晶体的光谱特征参数。

The radiative transition probabilities A JJ′ , nonradiative transition probabilities ω JJ′ and fluorescence lifetimes τ J of excited levels of Er 3+ ions in YLF crystal are calculated by using the Judd Ofelt theory. On the basis of equations of fluorescent dynamics the populations w J of excited levels, dependented on doped concentrations x, are calculated too. For 4I 11/2 → 4I 13/2 transition (at wavelength of 2.7 μm), only if doped concentration is bigger than 3 at.% the population inversion can be, and the fluorescence strength and doped concentration are increased. But for 4I 13/2 → 4I 15/2 transition (at wavelength of 1.73 μm), there is a optimal doped concentration for which the fluorescent strength is maximal. When the pump probabilty is 10 3￣10 5 s -1 , the x op is 1.8￣3.0 at.%. The spectral characteristic parameters of Er 3+ ions in YAG crystal are calculated. Based on the comparison the advantages of Er 3+ ∶YLF as a laser crystal are discussed.