温度对氟氧化物玻璃陶瓷中Tm3+荧光强度的影响

采用不同波长的红色脉冲光, 激发镶嵌有LaF₃:Tm³⁺纳米晶体颗粒的透明氟氧化物玻璃陶瓷样品, 测量了不同环境温度下样品的荧光发射谱, 记录了荧光发射强度随环境温度的变化规律.实验结果显示, 在643.2 nm 脉冲光激发下, 上转换454 nm 在100~200 K 的温度范围内有很强的荧光发射, 并且荧光强度随着环境温度的降低先增强而后减弱; 当采用656.0 和638.0 nm 脉冲光激发样品时, 上转换荧光发射强度随环境温度的降低而逐渐增强, 其中643.2 和638.0 nm 脉冲光激发下的上转换效率高于656.0 nm 激发时的结果, 表明波长接近于激发态吸收的激发光泵浦样品时, 更容易实现Tm³⁺的频率上转换. 最后, 从基质声子分布特点等方面对实验结果给出了合理的解释.

Influence of temperature on the fluorescence intensity of Tm~(3+) doped in oxyfluoride glass ceramics

The sample of transparent oxyfluoride glass ceramics was excited by a red pulsed laser which had a tunable wavelength between 602 and 660 nm. The fluorescence intensities of Tm³⁺ ion under different temperatures were measured, and the relationship between them was also recorded. It was shown that the upconversion emission at 454 nm was very strong at 100–200 K under the excitation at 643.2 nm. The upconversion intensity increased initially and then decreased with the decrease of temperature, and the fluorescence intensities increased with the decrease of temperature under the excitations at 656.0 and 638.0 nm. Additionally, the efficiencies of the upconversion under 643.2 and 638.0 nm excitations exceeded that of 656.0 nm, which suggested us that it was easy to complete the upconversion when the excitation wavelength was resonant with the excited state absorption, and a proper theoretical explanation was proposed based on the upconversion mechanism of Tm³⁺, phonon energy, and so on.