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用提拉法成功生长出了优质的Cr3+:Gd3Sc2Ga3O12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→2T1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Cr3+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Cr3+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ΔE为204 cm-1,这些参数表明Cr3+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。
Cr3 +: Gd3Sc2Ga3O12 crystals were successfully grown by the Czochralski method. The absorption spectra at room temperature and the fluorescence spectra at different temperatures were measured. The crystal field parameters were calculated. The fluorescence peak and the crystal field parameters were found to be similar to those reported in the literature the same. In the absorption spectrum, the strong absorption band at 458.5nm and 642.5nm, corresponding to the absorption transitions of 4A2 → 4T1 and 4A2 → 4T2 of Cr3 +, respectively, and a very weak absorption peak at 678nm, which corresponds to 4A2 → 2T1 absorption transition. Fluorescence spectra and fluorescence lifetime of crystals from 7K to room temperature were tested. Broadband fluorescence appeared in the range of 650 ~ 850nm, corresponding to the emission transition of 4T2 → 4A2 of Cr3 +. With the increase of temperature, the fluorescence peak shifts to the direction of longwave, the FWHM of the fluorescence peak increases, its fluorescence peak at room temperature is 732nm, and the FWHM is about 80nm. In the fluorescence spectrum at low temperature (7K), a sharp R line (zero phonon) was observed at 694 nm, corresponding to the emission transition of 2E → 4A2 of Cr3 +. Due to the temperature quenching effect, as the temperature rises, the fluorescence lifetime of the crystal decreases, and the fluorescence lifetime at room temperature is about 114 μs. The calculated field strength parameter Dq / B = 2.49, 4T2 pitch phonon level and 2E level spacing ΔE of 204 cm-1, these parameters indicate that Cr3 + in a weak crystalline field, which is conducive to 4T2 → 4A2 Broadband transition, Cr: GSGG crystal is the ideal tunable laser working substance.