Optical transitions in Mn3+-doped garnets
Optical transitions in Mn3+-doped garnets
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DOI：
10.1103/physrevb.57.2203
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发表时间：
1998-01-15
影响因子：
3.7
通讯作者：
Petermann, K
中科院分区：
文献类型：
--
作者：
Kuck, S;Hartung, S;Petermann, K
掺杂Mn 3+的石榴石晶体的光谱揭示了E-5基态的约1900 cm（-1）的大Jahn-Teller稳定化能量，以及激发态的较小Jahn-Teller稳定化能量，即，对于T-5（2），约为325 cm（-1），对于T-1（2）节段，约为180 cm（-1）。吸收光谱由自旋允许的E-5 → T-5（2）跃迁控制。在低温下，从T-1（2）能级到Jahn-Teller分裂基态和T-3（1）中间能级的发射发生。随着温度的升高，T-5（2）能级变得热布居，并且发射光谱由自旋允许的T-5（2）-> E-5跃迁主导。发射寿命几乎与探测波长无关，但强烈依赖于温度和基质晶格。在12 K时，所有晶体的寿命都接近6 ms，而在室温时，Mn ~（3+）：Y_3Al_5 O_（12）的寿命在1.1ms和Mn ~（3+）：Gd_3Sc_2Ga_3 O_（12）的< 0.5 μ s之间。T-1（2）和T-5（2）能级的辐射寿命分别约为6 ms和16 μ s。由于奇宇称和全对称声子的耦合以及T-5（2）能级的热化，辐射和非辐射速率都与温度有关。由于T-5（2）-T-3（1）能隙更小，T-5（2）能级的布居数更高，因此晶体场强越低，非辐射衰减越明显。激发态吸收跃迁产生于能量较低的T-1（2）在较高的单重态能级覆盖整个光谱范围的发射，因此在室温下的激光振荡是不可能的Mn 3+掺杂石榴石。
The optical spectra of Mn3+-doped garnet crystals reveal a large Jahn-Teller stabilization energy of about 1900 cm(-1) for the E-5 ground state, and smaller Jahn-Teller stabilization energies for the excited states, i.e., approximate to 325 cm(-1) for the T-5(2), and approximate to 180 cm(-1) for the T-1(2) level. The absorption spectra are dominated by the spin-allowed E-5 --> T-5(2) transition. At low temperatures, the emission occurs from the T-1(2) level to the Jahn-Teller-split ground state and the T-3(1) intermediate level. With increasing temperature the T-5(2) level becomes thermally populated and the emission spectrum is dominated by the spin-allowed T-5(2) --> E-5 transition. The emission lifetime is nearly independent of the detection wavelength, but strongly dependent of the temperature and the host lattice. At 12 K the lifetime is approximate to 6 ms for all crystals, while at roam temperature it is between 1.1 ms for Mn3+:Y3Al5O12 and < 0.5 mu s for Mn3+:Gd3Sc2Ga3O12 The radiative lifetimes of the T-1(2) and T-5(2) levels were determined to be about 6 ms and 16 mu s, respectively. Both the radiative and the nonradiative rate are temperature dependent due to the coupling of odd-parity and totally-symmetric phonons, and the thermalization of the T-5(2) level. The nonradiative decay is more pronounced for lower crystal-field strengths, because of the smaller T-5(2)-T-3(1) energy gap and the higher population of the T-5(2) level. Excited-state absorption transitions arising from the energetically lower T-1(2) in higher lying singlet levels cover the entire spectral range of the emission; therefore laser oscillation at room temperature is unlikely in Mn3+-doped garnets.