采用提拉法生长了最大尺寸为25 mm×(30-40)mm优质透明的Tm^3+∶GGG、Yb3+/Tm^3+∶GGG、Cr^3+/Tm^3+∶GGG、Tm^3+/Ho^3+∶GGG和Cr^3+/Tm^3+/Ho^3+∶GGG共五种晶体。在室温下测试了这些晶体的吸收光谱、荧光光谱及荧光衰减曲线等,详细研究了光谱性能,对部分晶体进行了Judd-Ofelt理论计算,得到强度参数等重要的光谱参数。计算了-2.0μm附近荧光峰值波长处相应的能级跃迁的发射截面、量子效率等。研究表明:Yb3+和Cr^3+的掺入分别使得Tm∶GGG晶体在980 nm附近和451 nm、628 nm附近的吸收大大增强,有利于商业激光二极管和闪光灯泵浦。在Tm激活的Tm^3+∶GGG、Yb3+/Tm^3+∶GGG、Cr^3+/Tm^3+∶GGG晶体中,-2.0μm波段附近发射强度和发射截面值最大的峰值对应的波长为2000 nm;而在Ho激活的Tm^3+/Ho^3+∶GGG和Cr^3+/Tm^3+/Ho^3+∶GGG晶体中,发射强度和发射截面最大的峰值对应的波长为2080 nm。用氙灯抽运键合的尺寸为5 mm×45 mm Cr^3+/Tm^3+/Ho^3+∶Gd3Ga5O12晶体,在2.086-2.102μm波段实现了平均功率为170 mW的激光输出。
High quality Tm^3+∶GGG,Yb3+/ Tm^3+∶GGG,Cr^3+/ Tm^3+∶GGG,Tm^3+/Ho^3+∶GGG and Cr^3+/Tm^3+/Ho^3+∶GGG crystals with the largest size 25 mm×(30-40) mm have been grown by Czochralski method.The absorption spectra,fluorescence spectra as well as fluorescence decay curves of all these crystals were measured at room temperature.The spectral properties were discussed,and Judd-Ofelt theory was used on some crystals to obtain intensity parameters and other important spectral parameters.The emission cross-sections,quantum efficiency of the transitions corresponding to ~2.0 μm wavelength were calculated.The results show that the codopant Yb3+ and Cr^3+ made the absorption of Tm∶GGG crystal in the bands with peaks near 980 nm and near 451 nm,628 nm much stronger,which are suitable for pump by LD and Xenon lamp effectively.In the Tm^3+ activated crystals,e.g.Tm^3+∶GGG,Yb3+/Tm^3+∶GGG,Cr^3+/Tm^3+∶GGG crystals,the strongest emission locates at ~2.0 μm;while in the Ho^3+ activated crystals,e.g.Tm^3+/Ho^3+∶GGG,Cr^3+/Tm^3+/Ho^3+∶GGG crystals,the strongest emission locates at ~2.08 μm.Laser characteristics of Cr^3+/Tm^3+/Ho^3+∶Gd3Ga5O12 crystal with size 5 mm×45 mm were measured using the Xenon flash-lamp as the pumping source and 170 mW laser output was achieved within the range of 2.086-2.102 μm.