Critical separation for efficient Tm3+ -Tm3+ energy transfer evidenced in nanostructured Tm3+: Al2O3 thin films.
Critical separation for efficient Tm3+ -Tm3+ energy transfer evidenced in nanostructured Tm3+: Al2O3 thin films.
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DOI：
10.1364/ol.33.000608
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发表时间：
2008-03
期刊：
影响因子：
3.6
通讯作者：
Zhisong Xiao;Rosalía Serna;Fei Xu;Carmen N. Afonso
中科院分区：
文献类型：
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作者：
Zhisong Xiao;Rosalía Serna;Fei Xu;Carmen N. Afonso
采用交替脉冲激光沉积法制备了掺Tm 3+的纳米非晶Al_2 O_3薄膜。的Tm 3+离子已被沉积在层与深度分离范围从0.75至6 nm。薄膜显示出两个宽的发射带，分别来自Tm ~（3+）~ 3 H ~ 4 → ~ 3F ~ 4和~ 3F ~ 4 → ~ 3 H ~ 6跃迁。它们的强度以相似的速率增加，并且当层间距减小到1.5 nm时，寿命没有改变，这表明没有浓度猝灭。在1.5nm的临界值处，Tm 3 + -Tm 3+能量转移的开始由发射强度和寿命的急剧下降证明。在这个临界值以下，3F 4-> 3 H6跃迁的强度增加速率比3 H4-> 3F 4跃迁的强度增加速率高得多，证明3 H4-> 3F 4跃迁通过交叉弛豫机制猝灭。Tm 3+离子在纳米尺度上的控制允许证明离子之间的能量转移过程的开始，并提供了一条优化紧凑的光子增益集成器件的途径。
Nanostructured amorphous Al oxide (a-Al2O3) thin films doped with Tm3+ were synthesized by alternate pulsed laser deposition. The Tm3+ ions have been deposited in layers with in-depth separation ranging from 0.75 to 6 nm. The films show two broad emission bands originated from the Tm3+ 3H4-->3F4 and 3F4-->3H6 transitions. Their intensity increases at a similar rate and the lifetimes are not modified as the layer separation decreases down to 1.5 nm, suggesting that there is no concentration quenching. At the critical value of 1.5 nm the onset of Tm3+ -Tm3+ energy transfer is evidenced by a sharp decrease of the emission intensity and lifetime. Below this critical value, the rate at which the intensity increases for the 3F4-->3H6 transition is much higher than that for the 3H4-->3F4 transition, evidencing quenching of the 3H4-->3F4 transition through a cross-relaxation mechanism. The control of the Tm3+ ions in the nanometer scale allows evidencing the onset of energy transfer processes among ions and offers a route to optimize compact photonic gain integrated devices.