摘要
用提拉法成功生长出了优质的Cr3^＋：Gd，Sc2Ga2O12晶体，测定了室温下的吸收光谱和不同温度下的荧光光谱，计算了晶场参数，发现荧光峰值及晶场参数与以前文献报道的均不相同。吸收光谱中，在458．5nm和642．5nm出现了较强的宽带吸收峰，分别对应于Cr3^＋的^4A2→^4T1和^4A2→^4T2孔的吸收跃迁，在678nm处又叠加了一个非常弱的吸收峰，对应于^4A2→^4T1的吸收跃迁。测试了晶体从7K到室温的荧光光谱和荧光寿命，在650～850nm范围内出现了宽带荧光，对应于Cr^3＋的^4T2→^4A2的发射跃迁。随着温度的升高，荧光峰向长波方向移动，荧光峰半高宽增大，室温下其荧光峰值在732nm，半高宽约为80nm。低温（7K）下的荧光谱中，在694nm处观察到了尖而锐的R线（零声子线），对应于Cr^3＋的^2E→^4A2的发射跃迁。由于温度猝灭效应，随着温度升高，晶体的荧光寿命降低，室温下荧光寿命约为114μs。计算了晶场强度参数Dq／B=2．49,^4T2零声子能级与^2E能级的间距AE为204cm^-1，这些参数表明Cr^3＋处在较弱的晶场中，有利于^4T2→^4A2的宽带跃迁，Cr：GSGG晶体是较为理想的可调谐激光工作物质。
The Cr：GSGG crystal with high quality was successfully grown by CZ method. The absorption and fluorescence spectra were measured and the crystal field parameters were calculated. It was discovered that the fluorescence peak wavelength and crystal field strength values of our crystal are different from the ones reported in the literature. The absorption spectrum shows that there are two strong absorption wideband peaks and a weak absorption peak belonging to Cr^3＋ ions wavelengthes are 458.5, 642.5 and 678nm, which correspond to ^4A2→^4T1,^4A2→^4T2 and ^4A2→^2T1 transitions respectively. The fluorescence spectrum at room temperature consists of only a broad band in the range of 650-850nm, corresponding to ^4T2→^4A2 transition. The emission peak shifts toward long the wavelength and the half width of fluorescence band increases with the increasing temperature at room temperature, the fluorescence peak locates at 732nm and the half width of fluorescence band is 80nm. At 7K temperature, a sharp emission peak locates at 694nm, corresponding to ^2E→^4A2 transition. The fluorescence lifetime decreases with the increasing temperature due to the temperature quenching effect, and the value is 114μs at room temperature. The results of crystal field parameters calculation indicate that the Cr^3＋ ions locate at a weak crystal field, which is helpful to the ^4T2→^4A2 transition with a board band, therefore, the Cr：GSGG is a very promising tunable laser medium.
出处
《人工晶体学报》
EI
CAS
CSCD
北大核心
2006年第1期114-118,共5页
Journal of Synthetic Crystals
基金
国家自然科学基金(No.50472104No.60478025)
关键词
Cr:GSGG晶体
吸收光谱
荧光光谱
荧光寿命
Cr： GSGG crystal
absorption spectra
fluorescence spectra
fluorescence lifetime
