Tm:YAP激光晶体光谱参数的计算

采用丘克劳斯基(Czochralski)法生长了Tm:YAP晶体,研究了该晶体在室温下的吸收光谱和荧光光谱.结果表明,Tm:YAP晶体在689.5 nm和795 nm左右有较强的吸收峰,分别对应于3H6→3F3和3H6→3H4的能级跃迁,半峰全宽(FWHM)分别为22.5 nm和30 nm,吸收截面分别为1.89×10-20 cm2和1.35×10-20 cm2.荧光光谱表明Tm:YAP晶体发射波长为1.89μm,相应的荧光寿命为13.90 ms,发射截面为1.58×10-19 cm2.根据乍得-奥菲特(Judd-Ofelt)理论计算了Tm3+在Tm:YAP晶体中的强度参数:Ω2=1.4560×10-20cm2,Ω4=2.0673×10-20 cm2,Ω6=0.3181×10-20 cm2.结果表明,Tm:YAP晶体具有宽的吸收峰、长荧光寿命和较大的积分发射截面的性质,非常适合于激光二极管(LD)抽运,有利于获得低阈值高效率的2μm波段激光输出.

Spectral Properties of Tm:YAP Laser Crystal

Tm:YAP crystals doped with 4 at.-% Tm3+ ions have been obtained by the Czochralski technique. Absorption and fluorescence spectra of the crystals have been measured at room temperature. The most intensive absorption peaks occur around at wavelengths of 689.5 nm and 795 nm, which are corresponding to the transitions of Tm3+ ions 3H6→3F3 and 3H6→3H4, respectively. The absorption cross sections are 1.89×10-20 cm2 and 1.35×10-20 cm2 with full width of half maximum (FWHM) of 22.5 nm and 30 nm respectively. The strong emission peak is centered at about 1.89 μm, the fluorescence lifetime is about 13.90 ms, and emission cross section is 1.58×10-19 cm2. According to Judd-Ofelt theory, the intensity parameters Ωt (t=2,4,6) of Tm3+ ion have been calculated as Ω2=1.4560×10-20 cm2, Ω4=2.0673×10-20 cm2, and Ω6=0.3181×10-20 cm2. Experimental results show that Tm:YAP crystal is a potential candidate for compact, efficient mid-infrared lasers at 2 μm output with laser diode (LD) pumping.