Grupo de Fotônica e Fluidos Complexos, Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió, Alagoas, Brazil.
J Chem Phys. 2010 Jul 21;133(3):034507. doi: 10.1063/1.3457926.
Pump and thermally induced color tunabilities were demonstrated in Yb(3+)/Tm(3+) codoped low silica calcium aluminosilicate (LSCAS) glass under anti-Stokes excitation at 1.064 microm. The effects of pump intensity and sample's temperature on the upconversion emissions and mainly on the color tunabilities (from 800 to 480 nm) were investigated. The results revealed a 20- and a threefold reductions at 800/480 nm ratio as, respectively, the pump intensity and sample's temperature were increased from 27 to 700 kW/cm(2) and from 296 to 577 K. These behaviors with pump intensity and temperature (a strong increase of the 480 nm emission in comparison with the 800 nm one) were attributed to the several efficient processes occurring in the LSCAS system (Yb(3+)-->Tm(3+) energy-transfer processes, easy saturations of the Yb(3+) and Tm(3+) excited states, and radiative emissions). Besides these assigns, the temperature dependence is mainly assigned to the temperature-dependent effective absorption cross section of the ytterbium sensitizer through the so-called multiphonon-assisted anti-Stokes excitation process. Theoretical analyses and fits of the experimental data provided quantitative information.
在反斯托克斯激发下，研究了掺铥和掺镱的低硅钙铝硅酸盐（LSCAS）玻璃在 1.064μm 处的泵浦和热诱导颜色可调谐性。研究了泵浦强度和样品温度对上转换发射的影响，主要是对颜色可调谐性（从 800nm 到 480nm）的影响。结果表明，当泵浦强度从 27kW/cm(2)增加到 700kW/cm(2)，而样品温度从 296K 增加到 577K 时，在 800nm/480nm 比上分别有 20 倍和 3 倍的降低。这些与泵浦强度和温度相关的行为（与 800nm 相比，480nm 发射的强烈增加）归因于 LSCAS 系统中发生的几个有效过程（Yb(3+)到 Tm(3+)的能量转移过程、Yb(3+)和 Tm(3+)激发态的容易饱和以及辐射发射）。除了这些分配，温度依赖性主要归因于通过所谓的多声子辅助反斯托克斯激发过程， ytterbium 敏化剂的温度相关有效吸收截面。理论分析和实验数据的拟合提供了定量信息。
