利用窄得-奥菲特理论研究Tm:Lu_2SiO_5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.

A new silicate laser crystal, Tm:Lu<inf>2</inf>SiO<inf>5</inf> (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 Ω<inf>2</inf> = 9.1355 × 10^-20 cm², Ω<inf>4</inf> =8.4103 × 10^-20 cm², Ω<inf>6</inf> = 1.5908 × 10²⁰ cm². Some main emission peaks exist around 1.9μm, corresponding to ³F<inf>4</inf> &rarr ³H<inf>6</inf> transition. Fluorescence lifetime and integrated emission cross-section, corresponding to ³F<inf>4</inf> &rarr ³H<inf>6</inf> 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.