【摘要】 在 978nm激光二极管的激发下 ,Mo掺杂的TiO2 材料表现出很强的宽带上转换发光 ,该发光来源于 [MoO4]2 - 基团的激发态3T1 ,3T2 能级到基态1 A1 能级的电子跃迁 .通过研究发光强度与抽运功率的关系及上转换发光的上升时间曲线 ,发现TiO2 ∶Mo体系的上转换发光中存在着雪崩机制 ,应用转换函数理论分析了光子雪崩的产生条件和主要特征 ,理论结果和实验数据很好地符合更多还原

【Abstract】 The Mo-doped titania exhibits a visible broadband emission under a 978 nm laser diode excitation. The luminescence has been assigned to the transitions from the excited states 3T 1, 3T 2 to the ground state 1A 1 of the [MoO 4] 2- radical. In TiO 2∶Mo system, the power dependence of the upconversion-luminescence intensity exceeds a quadratic dependence, and the time evolution of the upconversion luminescence after the onset of continuous wave excitation is characterized by a rise time of 63 ms. These properties show the typical fingerprints of a photon avalanche. No luminescence was observed from the sample when excited with a pulsed laser (1064 nm) from a Nd∶YAG or a pulsed Raman-shift laser (953 6nm) pumped by a second harmonic of the Nd∶YAG. Regardless of the energy mismatch between the pulsed laser and the continuous wave diode laser, another reason may be that the duration time of a single laser pulse (10 ns) is much shorter than the rise time of the photon avalanche. The fluorescence “transfer function” theory is used to study the luminescence dynamics, which provides a good description of the experimental data.更多还原