De Michele Vincenzo, Sciortino Alice, Messina Fabrizio, Cannas Marco, Boukenter Aziz, Marin Emmanuel, Girard Sylvain, Ouerdane Youcef
Opt Lett. 2021 Apr 1;46(7):1736-1739. doi: 10.1364/OL.420198.
We report a set of femtosecond (fs) transient absorption (TA) measurements following the dynamics of the so-called nonbridging oxygen hole center in silica, a model color center in wide bandgap amorphous solids, characterized by a very large Stokes shift between the UV excitation and its associated red emission at 1.9 eV. The changes in the TA spectrum were probed in the UV-visible range at various delays after photoexcitation and analyzed as a function of the UV excitation energy, in single-photon absorption conditions. The combination of the experiments helps to clarify the defect photocycle, highlighting how TA measurements with tunable UV excitation could represent a powerful tool to investigate the dynamics of color centers embedded in transparent materials.
我们报告了一组飞秒（fs）瞬态吸收（TA）测量结果，该测量跟踪了二氧化硅中所谓的非桥氧空穴中心的动力学过程。二氧化硅是宽带隙非晶态固体中的一种模型色心，其特征在于紫外激发与其在1.9 eV处相关的红色发射之间存在非常大的斯托克斯位移。在单光子吸收条件下，在光激发后的不同延迟时间，在紫外-可见光范围内探测TA光谱的变化，并将其作为紫外激发能量的函数进行分析。这些实验的结合有助于阐明缺陷光循环，突出了可调谐紫外激发的TA测量如何能够成为研究嵌入透明材料中的色心动力学的有力工具。
