摘要
采用提拉法从近化学计量比的熔体中生长出尺寸为20mm×50mm的优质LiNbO3:Cr:ZnO(CZLN)晶体,其光学均匀度为7.59(10-5)。进行了吸收和荧光光谱的测定研究。吸收谱测试表明:Cr3+离子在晶体中有2个宽且强的吸收带及1个微弱的吸收线,两宽带中心波长分别为480和660nm,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727nm,对应于4A2→2E(R线)的跃迁。荧光测试表明:当激发波长为660nm时,CZLN晶体荧光宽带和1个较弱的荧光线峰并存,宽带范围为802～988nm,峰值波长为871nm,对应于4T2→2E,4A2的联合能级跃迁,荧光线峰波长约为754nm,其强度较弱,相应于2E→4A2(零声子线)能级跃迁。计算了晶场强度和Racah参数,其DqB=2.72,晶体属于强场介质。研究表明,CZLN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420nm附近紫外的自倍频激光输出。
The LiNbO3 ：Cr：ZnO crystals with the size up to φ20 min×50 mm were grown by the Czochralski technique. The absorption spectrum shows that there are two strong absorption wideband peaks and one weak absorption peak of to Cr^3 ＋ ion in the crystal. The peak values of the two strong absorption wideband peaks are 480 and 660 nm, which correspond to ^4A2→^4T1 and ^4A2→^4 T2 transitions, respectively. The weak absorption peak at 727 nm corresponds to ^4A2→^2 E（R line） transition; The fluorescence spectrum shows that one emission wideband peak ranging from 802 to 988 nm coexists with one weak emission peak at 754 nm corresponding to ^4T2 →^2E transition. The peak value of emission widehand is at 871 nm, which corresponds to ^4T2→^4A2 transition. The crystal field and Racah parameters were calculated, and Dq/B = 2.72 indicates that it has an stronger crystal field. The result shows that the wideband tunable lair can be obtained from this crystal because it not only has the necessary spectral characteristics required for tunable laser crystal but also has good physical chemical properties. Furthermore, the UV laser at about 420 nm can also be obtained from the crystal by its self-frequency doubling because it has a higher frequency-doubling coefficient.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2006年第1期1-5,共5页
Spectroscopy and Spectral Analysis
基金
福建省科技资助项目(2002I016)
