Cr^(3+):GdAl_3(BO_3)_4晶体生长和光谱特性的研究

Study on the Growth and Spectral Characteristics of Cr^(3+):GdAl_3(BO_3)_4 Crystal

采用顶部籽晶法从K2 Mo3 O10 +B2 O3 助熔剂体系生长出尺寸为 30mm的Cr3 + :GAB晶体 ,吸收谱测试表明 :Cr3 + 离子在晶体中有两个宽且强的吸收带及一个微弱的吸收线 ,两宽带中心的波长为 4 2 0和 5 95nm ,对应于 4A2 →4T1和4A2 →4T2 两个具有相同的总自旋能级之间的跃迁 ,在4A2 →4T2 吸收宽带的长波边缘处有个很小的吸收峰 ,其波长为 6 81nm ,对应于 4A2 → 2 E(R线 )的跃迁。荧光测试表明 :Cr3 + :GdAl3 (BO3 ) 4(CGAB)晶体荧光宽带和一个较弱的荧光线峰并存 ,宽带范围为 6 5 0～ 85 0nm ,峰值波长为 72 3nm ,对应于4T2 → 2 E ,4A2 的联合能级跃迁 ,荧光线峰波长约为 70 0nm ,其强度较弱。计算了晶场强度和Racah参数 ,其中Dq/B =2 371,晶体属于中阶场介质。研究表明 ,CGAB晶体具备可调谐激光晶体的基本光谱要求 ,且有良好的物化性能 ,可以实现宽频带可调谐激光输出。它又具有较大的倍频系数 ,有望实现 35 0nm附近紫外的自倍频激光输出。

The Cr 3+ :GdAl_3(BO_3)_4 crystals with the sizes up to 30 mm were grown from the K_2Mo_3O_ 10 +B_2O_3 solvent system by using the TSSG method. The absorption spectrum shows that there are two strong absorption wideband peaks and one weak absorption peak belonging to Cr 3+ ion in the crystal. The peak wavelengths of the two strong absorption wideband peaks are 420 and 595 nm, which correspond to 4 A _2→ 4 T _1 and 4 A _2→ 4 T _2 transitions respectively. The weak absorption peak at 681 nm corresponds to 4 A _2→ 2 E ( R line) transition. The fluorescence spectrum shows that one emission wideband peak ranging from 650 to 850 nm coexists with one weak emission peak at 700 nm corresponding to 4 T _2→ 2 E transition. The peak wavelength of the emission wideband is 723 nm, which corresponds to 4 T _2→ 4 A _2 transition. The crystal field and Racah parameters wre calculated. The result shows that this crystal may be useful as a tunable red laser and as a tunable UV laser at about 350 nm.