Tb，Tm：YVO4晶体的激光性能分析

Tm：YVO4和Tb，Tm：YVO4晶体中激活离子之间或激活离子与敏化离子间的交叉弛豫、与无辐射跃迁及激光上能级的辐射跃迁的几率是相近的，对这种双掺离子晶体的激光阈值理论估算式中必须同时考虑离子间交叉弛豫。从激活离子能级跃迁速率方程和激光、抽运光传输方程推导出端面抽运的包含交叉弛豫几率等光学参量的激光阈值的理论估算式。用这些方程讨论了Tm：YVO4和Tb，Tm：YVO4的1．5μm和1．9μm波长的激光性能，并论述了Tb3 离子的作用。结果表明。Tb3 离子的的掺入，增加1．5μm波段激光的强度，降低阈值能量，但对1.9μm波长激光有负面作用。

The Study on Lasing Performance of Tb,Tm∶YVO4 Crystal

The order of magnitude of the cross relaxation propability between active ions and sensitive ions in Tb,Tm∶YVO 4 crystal and the cross relaxation among active ions in Tm∶YVO 4 are close with that of the non radiating transition probability and the radiant transition probability of higher level to lower level. The formula to estimate the laser threshold in the crystal including two sort codoped ions must take into account the cross relaxation among the ions. The estimated formula of the laser threshold including the probability of the cross relaxation among the ions is deduced from the transition rate equations and transmission equations of lasing and pumping light for end-pumped laser. The lasing performance of Tm∶YVO 4 and Tb,Tm∶YVO 4 at 1.5 μm and 1.9 μm wavelengths is discussed with these threshold equations, the action of Tb 3+ ions is also expounded. The results show that doping Tb 3+ ions in Tm∶YVO 4 increases intensity of lasing light and minifies the laser threshold at 1.9 μm wavelength.