利用窄得-奥菲特理论研究Tm:Lu2SiO5晶体的光谱特性

采用丘克拉斯基(Czochralski)技术生长了掺铥硅酸镥(Tm∶Lu2SiO5,Tm∶LSO)晶体;测量了LSO晶体在室温下的非偏振吸收光谱和非偏振荧光光谱;利用窄得-奥菲特(Judd-Ofelt)理论计算了Tm∶LSO晶体的窄得-奥菲特强度参数、振子强度、自发辐射概率、辐射寿命、积分吸收截面和积分发射截面.Tm∶LSO晶体的强度参数为Ω2=9.1355×10-20cm2,Ω4=8.4103×10-20cm2,Ω6=1.5908×10-20cm2;Tm∶LSO晶体在1.9μm附近有明显的发射峰(3F4→3H6跃迁),相应的辐射寿命为2.03 ms,积分发射截面为5.81×10-18cm2,半峰全宽(FWHM)为250 nm.用Tm∶LSO晶体在77 K温度下实现了激光运转.利用792 nm的激光二极管(LD)作为抽运源,获得中心波长为1960 nm的激光输出,抽运阈值为2.13 kW/cm2.

Judd-Ofelt Analysis of Spectroscopic Properties of Tm3+ Doped Lu2SiO5 Crystals

A new silicate laser crystal, Tm:Lu2SiO5 (Tm:LSO) crystal, has been obtained by the Czochralski technology. Absorption spectra and fluorescence (un-polarized) spectra of Tm:LSO have been measured at room temperature. Parameters such as Judd-Ofelt intensive parameters, oscillator strength, spontaneous radiation rate, fluorescence lifetime, integrated absorption cross-section, integrated emission cross-section were calculated by Judd-Ofelt theory. Intensive parameters were calculated to be Ω2=9.1355×10-20 cm2, Ω4=8.4103×10-20 cm2, Ω6=1.5908×10-20 cm2. Some main emission peaks exist around 1.9 μm, corresponding to 3F4→3H6 transition. Fluorescence lifetime and integrated emission cross-section, corresponding to 3F4→3H6 transition, were calculated to be 2.03 ms and 5.81×10-18 cm2, respectively. Laser actions have been obtained by use of Tm:LSO crystal at the temperature of 77 K. The central laser wavelength of 1960 nm and pumping threshold of 2.13 kW/cm2 were obtained.