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用提拉法成功生长出3种不同掺Eu3+浓度的优质Yb,Er,Eu:YAP激光晶体,并对其光谱特性进行了研究。测量了晶体在320~3 000nm波段内的吸收光谱,晶体在978nm附近有强的吸收峰和宽的吸收带。用波长为975nm的LD连续激光和OPO光参量脉冲激光激发分别获得了晶体的稳态和瞬态荧光光谱,采用单指数衰减拟合得到2.7~3.0μm激光上下能级寿命。与单掺Er:YAP晶体的光谱参数进行了比较,对Yb3+的敏化及Eu3+的退激活机理进行了分析。结果表明,Yb3+和Eu3+可分别作为Er3+的敏化剂和退激活剂,增宽978nm附近的吸收带和降低激光下能级(4I13/2)与上能级(4I11/2)寿命的比值(4.1,3.1和2.7);而在单掺Er:YAP晶体,下能级与上能级寿命的比值高达10.8,不利于激光性能的提高。因此,Yb,Er,Eu:YAP是一种更适合LD泵浦,有望实现低阈值、2.7~3.0μm高效率激光输出的新型激光晶体。
Three kinds of high quality Yb, Er, Eu: YAP laser crystals with different concentrations of Eu3 + were successfully grown by Czochralski method and their spectral characteristics were studied. The absorption spectrum of the crystal in 320-3000 nm band was measured. The crystal has a strong absorption peak near 978 nm and a broad absorption band. The steady-state and transient fluorescence spectra of the crystals were obtained by using the laser of 975nm wavelength and the OPO optical parametric pulsed laser excitation respectively. The lifetimes of 2.7 ~ 3.0μm laser were obtained by single exponential decay. Compared with the single-doped Er: YAP crystal, the sensitization of Yb3 + and the deactivation mechanism of Eu3 + were analyzed. The results show that Yb3 + and Eu3 + can be used as sensitizers and deactivators of Er3 +, respectively, widening the absorption band near 978 nm and reducing the ratio of the lifetime under the laser (4I13 / 2) to the upper (4I11 / 2) 4.1, 3.1 and 2.7). However, in single-doped Er: YAP crystals, the ratio of the lower level to the upper level is as high as 10.8, which is unfavorable to the enhancement of laser performance. Therefore, Yb, Er, Eu: YAP is a new type of laser crystal that is more suitable for LD pumping and is expected to achieve a low threshold, high efficiency laser output of 2.7 ~ 3.0μm.