掺Tm激光晶体的可见与红外发光转换及双稳多色开关

理论研究了648nm激光抽运掺Tm晶体的可见与红外发光转换和发光双稳特性.根据系统的耦合速率方程理论，推导了发光转换阈值的解析表达式，数值研究了Tm³⁺能级布居数，辐射光谱以及发光强度等随抽运光强的变化.数值结果表明，648nm激光抽运下可以实现452/469nm蓝光与1716 nm红外光谱的发光转换.在光子雪崩阈值附近，可以观察到掺Tm晶体的辐射光谱双稳，荧光色度双稳和发光强度双稳等现象.利用掺Tm晶体的可见与红外发光转换与双稳特性，可以实现抽运功率控制的全固态发光转换器和双稳波长 关键词： 光学双稳 多色开关 掺Tm晶体 光子雪崩

Chromatic bistability and luminescence switching of visible-infrared emission in Tm-doped laser crystal

Optical bistability and luminescence switching of visible-infrared emission in Tm-doped laser crystal pumped at 648nm avalanche wavelength is predicted theoretically and studied numerically. The analytical formula of luminescence switching threshold is deduced using the theory of nonlinear rate equations. The evolutions of populations of Tm³⁺ energy levels, emission spectrum and fluorescence intensity versus pump power are investigated numerically. The numerical results predict that the luminescence switching between 452/469nm blue and 1716nm infrared spectra can be experimentally realized under 648nm laser pumping. Moreover, the bistability of emission spectra, chromatic fluorescence and luminescence intensity in Tm-doped crystal can be observed in the vicinity of photon avalanche threshold. The characteristics of chromatic bistability and luminescence switching in Tm-doped crystal allow for the tailoring of pump-controlled all-solid luminescent switcher and bistable wavelength switch operating in visible-infrared spectral range.