【摘要】 用坩埚下降法生长了Tm³⁺掺杂浓度分别为0.8%和1.3%的优质大尺寸LiYF₄（LYF）单晶体。测定了单晶体的吸收光谱、发射光谱,并计算了³F₄能级的的最大吸收截面与最大发射截面分别为0.25×10^-20 cm²和0.33×10^-20 cm²。以796 nm半导体激光器（LD）为泵浦源,采用短平板腔结构模型研究了Tm掺杂LYF单晶体在～2.0μm波段的激光输出性能。当LD泵浦功率为3.4 W时,Tm∶YLF晶体的最大激光输出功率为1.88 W,相应的光光转换效率和斜率效率分别为51%和57%。使用半导体可饱和吸收镜抽运Tm掺杂LYF单晶体,测试其在～2.0μm波段连续波锁模激光运转。当最大抽运功率为3.5 W时,获得锁模激光的最大平均输出功率为200 mW,此时锁模脉冲宽度～20 ps,对应的重复频率63.86 MHz,中心谱线为1.88μm。结果表明,Tm掺杂LYF单晶体是一种具有较好物理性能的～2μm波段超快激光晶体。更多还原

【Abstract】 High quality LiYF₄（LYF） single crystals in big size doped with Tm³⁺ in 0.8% and 1.3% concentrations were grown by Bridgman method. The absorption spectra and emission spectra were measured. The maximum absorption cross section and maximum emission cross section of ³F₄ level were calculated to be 0.25×10^-20 cm² and 0.33×10^-20 cm², respectively. The laser output of Tm³⁺ doped LYF crystals in the ～2.0 μm band was carried out by using short flat-flat cavity taking 796 nm semiconductor laser as pumping source. A maximum CW output of 1.88 W at an absorbed pump power of 3.4 W was achieved from the Tm³⁺ doped LYF single crystal, and the corresponding conversion efficiency and slope efficiency for the laser output were 51% and 57%, respectively. A Tm-doped LYF single crystal was pumped using a semiconductor saturable absorption mirror, and its operation in a ～2.0 μm band CW laser was tested. When the maximum pump power is 3.5 W, the maximum average output power of the mode-locked laser is 200 mW. At this time, the mode-locked pulse width is about 20 ps, the corresponding repetition frequency is 63.86 MHz, and the center line is 1.88 μm. The results show that the Tm-doped LYF single crystal is a～2 μm band ultrafast laser crystal with good physical properties.更多还原