Efficient tri-wavelength actively Q-switched Yb:GAGG laser

An efficient acousto-optic Q-switched Yb-doped Gd₃Al_xGa_5−xO₁₂ (GAGG) (x = 0.5) laser is demonstrated. Under the absorbed pump power of 7.4 W, the maximum average output power of 1.4 W is obtained at the pulse repletion rate of 1 kHz , with the slope efficiency as high as 32%. The pulse width of 40 ns is achieved with the pulse energy and peak power of 1.4 mJ and 35 kW, respectively. What’ more, the output spectrum shows itself tri-wavelength in either CW or Q-switching mode. To our knowledge, this is the first time for realizing simultaneous tri-wavelength Yb:GAGG laser actively Q-switched operation.     

被动锁模复合环形腔掺饵光纤激光器的自启动分析

本文对被动锁模复合环形腔掺饵光纤激光器的自启动工作特性进行了分析，指出谐振腔内残余反射面的存在是阻碍激光器实现自启动锁模的主要原因。利用半导体激光器有源区的折射率随注入电流的变化而改变的特性，在谐振腔中获得了一个可移动腔镜，克服了腔内残余反射面的影响，实现了锁模的自启动。     

Wide-band,passively Q-switched Yb- and Tm-doped fibre laser using WSSe saturable absorber

A wide-band, passively Q-switched fibre lasers based on ytterbium- and thulium-doped fibre gain medium are proposed and demonstrated. The lasers employ a transition metal dichalcogenide, tungsten sulphoselenide as a saturable absorber (SA) which is prepared by mechanical exfoliation technique. By integrating the SA in the laser cavities, self-starting Q-switched at 1038 and 1982?nm are obtained. The generated pulses exhibit a microsecond pulse duration with few kilohertz repetition rate. The proposed SA has high potential as a new material to cater to the needs of various scientific, industrial and biomedical applications.     

输出镜透过率对Cr∶YAG被动调Q激光器的影响

对LDA端面泵浦Cr∶YAG被动调Q Nd∶YAG激光器的输出特性进行了深入细致的研究,重点分析了输出耦合镜的透过率(T=3%、8%、20%、30%、40%)对平均输出功率、脉冲宽度、重复频率、以及单脉冲能量和峰值功率的影响。研究结果表明:在特定的激光参数下,Cr∶YAG被动调Q Nd∶YAG激光器的某些输出参数由输出镜透过率决定。T=8%时可以获得最大输出功率与重复频率,而T=20%时,可以获得最窄脉冲宽度、最高峰值功率以及最大单脉冲能量。     

Tm,Ho声光调Q激光系统理论与实验研究

利用激光速率方程理论,对Tm,Ho激光系统计算预测得出最佳耦合输出透过率和调Q激光脉冲宽度.实验采用Tm, Ho:LuLF为增益介质,三向侧面泵浦,环形腔声光调Q.选用透过率20%和30%的输出镜作对比.在透过率20%耦合输出时,得到调Q激光脉冲能量最大为58.0 mJ,对应光光转换效率为1.45%;在透过率30%耦合输出时,得到调Q激光脉冲能量最大为62.9 mJ,对应光光转换效率1.57%,并且获得了最大动静比48.7%.激光脉冲宽度在注入能量3.25 J时为417.2 ns.与理论计算结果较为一致.     

LD端面泵浦的1.57μm内腔式OPO

1.57 μm波长激光为人眼安全波长激光。将KTP晶体置于一个由LD端面泵浦、声光调Q的Nd:YVO4晶体双凹谐振腔内,利用KTP表面镀膜建立了内腔式OPO,实现了重复率在5～40 kHz范围内1.57 μm脉冲激光的稳定输出。实验结果表明,激光的阈值将随声光调Q器重复率的增加而升高,重复率为5 kHz时得到最低阈值1.52 W。重复率为15 kHz、泵浦功率为3.7 W时,输出光平均功率为305 mW,脉冲宽度50 ns,峰值功率400 W。     

主动驱动/被动箝位型压电精密步进驱动器研究

提出一种基于直线动子主动驱动和定子被动箝位的新型的压电精密步进驱动器。该驱动器以仿生运动的原理，以压电陶瓷叠堆为动力源，采用双薄壁柔性铰链微变形结构，提高了该驱动器箝位的稳定性和步进旋转的稳定性。通过理论分析和实验研究，深入的揭示了该驱动器的运动特性。     

Investigation of continuous-wave and Q-switched microchip laser characteristics of Yb:YAG ceramics and crystals

Continuous-wave and passively Q-switched microchip laser performance of Yb:YAG ceramics and single-crystals was investigated. Highly efficient continuous-wave Yb:YAG laser performance was observed at 1030 nm and 1049 nm for both Yb:YAG ceramics and crystals with different transmissions of output couplers. The laser performance of Yb:YAG ceramic is comparable to that of Yb:YAG single crystal. Meanwhile, the laser performance of laser-diode pumped Yb:YAG/Cr⁴⁺:YAG all-ceramics- and all-crystals-combination passively Q-switched microchip lasers were investigated. Sub-nanosecond laser pulses with peak power over 150 kW were obtained with different Yb:YAG/Cr⁴⁺:YAG combinations. Linearly polarized laser was observed in Yb:YAG/Cr⁴⁺:YAG all-crystals combination and circular polarized laser was obtained in Yb:YAG/Cr⁴⁺:YAG all-ceramics combination. The best laser performance was obtained with Yb:YAG/Cr⁴⁺:YAG all-crystals combination.     

Q开关Nd:YAG激光治疗黑色文身的临床研究

目的：探讨Q开关Nd：YAG激光治疗黑色文身的临床效果。方法：采用Q开关Nd：YAG激光治疗黑色文身200例,能量密度4～8J/cm~2,脉冲宽度5～6ns,重复频率5Hz,光斑直径2～3mm。根据文身的性质需1～7个疗程,疗程间隔6～8周。结果：200例文身中190业余性文身经1～5次治疗,治愈率100%,10例专业性文身经4～7次治疗,治愈率90%。随访3～12个月,无一例发生继发性疤痕和永久性色素改变。结论：Q开关Nd：YAG激光能安全有效去除黑色文身,达到极佳的美容效果。     

Er3+2.79μm激光器转镜调Q系统的特性分析

当YSGG、GGG、GSGG、YAG、YLF作为基质材料时，Er3+的4I11/2 能级和4I13/2 能级之间能够跃迁产生2.7~3μm的激光，该波段激光在医疗、军事等方面有着重要的应用价值。在790nm泵浦光作用下，Er:YSGG作为工作物质可产生2.79μm激光。通过构建Er:YSGG能级跃迁的速率方程，对转镜调Q激光器的系统特性进行了理论分析，并在此基础上进行数值模拟，得出了在给定激光工作物质参数的情况下，系统的各个变量对转镜调Q激光器性能的影响。这些结论将为类似实验的设计和改进提供理论指导。