Influence of energy-transfer-upconversion on threshold pump power in quasi-three-level solid-state lasers.
Influence of energy-transfer-upconversion on threshold pump power in quasi-three-level solid-state lasers.
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DOI：
10.1364/oe.17.011935
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发表时间：
2009-07
期刊：
影响因子：
3.8
通讯作者：
J. Kim;J. Mackenzie;W. Clarkson
中科院分区：
文献类型：
--
作者：
J. Kim;J. Mackenzie;W. Clarkson
本文导出了考虑能量转移上转换效应的端面泵浦准三能级固体激光器阈值泵浦功率的简单解析表达式。该表达式表明ETU可以显著提高阈值泵浦功率，特别是在低增益激光器和具有明显三能级特征的激光器中，这是由于在上流形中需要高激发密度才能达到阈值。该分析已被应用于Er：YAG激光器工作在1645 nm的带内泵浦的Er，Yb光纤激光器在1532 nm。作为铒掺杂浓度的函数的阈值泵浦功率的预测值与测量值非常吻合。结果表明，非常低的铒掺杂水平（约0.25at.%或更少）以避免由于ETU导致的性能降低，即使在Er：YAG中的连续波激光条件下。
A simple analytical expression for threshold pump power in an end-pumped quasi-three-level solid-state laser, which takes into account the influence of energy-transfer-upconversion (ETU), is derived. This expression indicates that threshold pump power can be increased dramatically by ETU, especially in low gain lasers and lasers with pronounced three-level character due to the need for high excitation densities in the upper manifold to reach threshold. The analysis has been applied to an Er:YAG laser operating at 1645 nm in-band pumped by an Er,Yb fiber laser at 1532 nm. Predicted values for threshold pump power as a function of erbium doping concentration are in very good agreement with measured values. The results indicate that very low erbium doping levels (approximately 0.25 at.% or less) are required to avoid degradation in performance due to ETU even under continuous-wave lasing conditions in Er:YAG.