High stability and low noise laser-diode end-pumped Nd:YAG ceramic passively Q-switched laser at 1123 nm based on a Ti_(3)C_(2)T_(x)-PVA saturable absorber

We report a high repetition frequency, high power stability and low laser noise laser-diode(LD) end-pumped Nd: YAG ceramic passively Q-switched laser at 1123 nm based on a Ti_(3)C_(2)T_(x)-polyvinyl alcohol(PVA) film as a saturable absorber(SA). A Brewster polarizer(BP) and a birefringent crystal(BC) are incorporated to enable frequency selection and filtering for the passively Q-switched 1123 nm pulsed laser to improve the power stability and reduce the noise. When the pump power is 5.1 W, an average output power of 457.9 m W is obtained, corresponding to a repetition frequency of 1.09 MHz,a pulse width of 56 ns, a spectral line width of 0.65 nm, a power instability of ±0.92%, and a laser noise of 0.89%.The successful implementation of the “Ti_(3)C_(2)T_(x)-PVA film passively Q-switching” combined with “frequency selection and filtering of BP + BC” technology path provides a valuable reference for developing pulsed laser with high repetition frequency, high stability and low noise.

High-peak-power passively Q-switched 1.3 μm Nd:YAG/V^(3+):YAG laser pumped by a pulsed laser diode

We demonstrate a high-pulse-energy, short-pulse-width passively Q-switched（PQS） Nd：YAG∕V3t：YAG laser at 1.3 μm, which is end-pumped by a pulsed laser diode. During the PQS regime, a maximum total output pulse energy of 3.3 m J is obtained under an absorbed pump pulse energy of 21.9 m J. Up to 400 μJ single-pulse energy is realized with the shortest pulse width of 6.16 ns and a pulse repetition frequency of 34.1 k Hz,corresponding to a peak power of 64.9 k W. The high-energy laser pulse is operated in the dual wavelengths of 1319 and 1338 nm, which is a potential laser source for THz generation.

Three-nanosecond-equal interval sub-pulse Nd:YAG laser with multi-step active Q-switching

We demonstrate a three-nanosecond equidistant sub-pulse multi-step Q-switched Nd:Y3 Al5 O12(Nd:YAG) laser.In the time interval of 100–1000 ns, three pulses with the same nanosecond interval and the same peak power are obtained at the pulse width of 24 ns, 28 ns, and 36.6 ns, respectively.The energy is 32.5 m J, and the optical efficiency is 10.8%.The multi-step Q-switched method does not require the insertion of other optical elements into the traditional Q-switched laser, and it is very suitable to obtain pulse group output with several nanosecond pulse intervals.

Fabrication of narrow pulse passively Q-switched self-stimulated Raman laser with c-cut Nd:GdVO_4

Combining the self-stimulated Raman scattering technology and saturable absorber of Cr^(4+):YAG, a 1.17 μm c-cut Nd:GdVO_4 picosecond Q-switched laser is demonstrated in this paper. With an incident pump power of 10 W, the Q-switched laser with average power of 430 mW for 1.17 μm, pulse width of 270 ps, repetition rate of 13 kHz and the first order Stokes conversion efficiency of 4.3% is obtained. The Q-switched pulse width can be the narrowest in our research. In addition, the yellow laser at 0.58 μm is also achieved by using the LiB_3O_5 frequency doubling crystal.

High-repetition-rate 1.5 μm passively Q-switched Er:Yb:YAl3(BO3) 4 microchip laser

End-pumped by a 976 nm diode laser,a high-repetition-rate Er:Yb:YAl3(BO3)4 microchip laser passively Q-switched by a Co2+:MgAl2 O4 crystal is reported.At a quasi-continuous-wave pump power of 20 W,a 1553 nm passively Q-switched laser with the repetition rate of 544 kHz,pulse duration of 8.3 ns,and pulse energy of 3.9 μJ was obtained.To the best of our knowledge,the 544 kHz is the highest reported value for the 1.5 μm passively Q-switched pulse laser.In the continuous-wave pumping experiment,the maximum repetition rate of 144 kHz with the pulse duration of 8.0 ns and pulse energy of 1.7 μJ was obtained at the incident pump power of 6.3 W.

LD泵浦Er^(3+)/Yb^(3+):Lu_(2)Si_(2)O_(7)晶体kHz微型激光器

目前1.5μm LD泵浦的铒镱共掺玻璃/晶体被动调Q微型激光器广泛应用于激光测距、激光雷达等领域。随着激光器输出能量和重频的增加,玻璃面临突出的热效应问题,晶体的热导率是玻璃的10倍以上,有望能够实现比玻璃基质更大脉冲能量和更高重频的激光输出。文中报道了一种采用LD脉冲端面泵浦、铒镱共掺焦硅酸镥晶体为增益介质的1537 nm被动调Q微型激光器。通过优化泵浦光斑大小、输出镜透过率与调Q晶体初始透过率相匹配,实现激光输出重频与泵浦重频一致。最终实现了输出重频为1 kHz、单脉冲能量35μJ、脉冲宽度7 ns、峰值功率为5 kW、光束质量因子M^(2)=1.33的激光输出。以及输出重频为10 kHz、单脉冲能量10μJ、脉冲宽度10 ns、峰值功率为1 kW、光束质量因子M^(2)=1.51的激光输出。结果表明,Er^(3+)/Yb^(3+):Lu_(2)Si_(2)O_(7)晶体是实现高重频1.5μm激光输出的优良介质。文中研究结果对LD脉冲端面泵浦的kHz铒镱共掺晶体被动调Q人眼安全微片激光器具有重要的参考意义。

1.9 ns LD端面泵浦Nd:YVO_4/GaAs被动调Q激光器

研究了激光二极管端面泵浦Nd:YVO4/Ga As被动调Q激光器的输出特性。在连续光运转和调Q运转情况下,得到的激光最高输出斜效率分别为41.5%和11.4%。用一片700μm厚的Ga As薄片作为饱和吸收体,对1.06μm激光透过率为6.5%的平面镜作为15 mm谐振腔的耦合输出镜,得到的最短脉宽仅为1.9 ns。在泵浦功率由0.5 W上升到5.6 W的过程中,用T为6.5%和20%的输出镜得到的脉冲重复频率从18.7和23.9 k Hz分别上升到53和41.3 k Hz。两种输出镜透过率下得到的最大脉冲能量分别为8.5和13.3μJ,相应的峰值功率高达4.45和4.6 k W。此激光器具有非常高的振幅稳定性,在高泵浦功率下调Q脉冲振幅波动小于3%。

9 W级高功率SESAM锁模Nd∶YVO_4激光器

通过LD端面泵浦Nd∶YVO4晶体,以半导体可饱和吸收镜(SESAM)作为被动锁模器件,利用ABCD传输矩阵法和MATLAB软件设计具有良好热稳定性和超大稳区的X-型五镜折叠谐振腔,实现了高效率和高功率的连续稳定锁模运转.在泵浦功率30 W时得到1 064nm波长最大9W的稳定锁模输出,脉冲重复频率为108.28MHz,脉宽为9.53ps,对应最大单脉冲能量84.04nJ,激光器的斜效率达到31.7%.以此为种子源放大可直接获得百瓦级高功率锁模激光输出.

基于Nd:YAG陶瓷的被动锁模激光器研究

Nd:YAG陶瓷具有可大尺寸、低成本制备的特点,但基于Nd:YAG陶瓷的锁模激光器尚未得到大量验证。采用Nd:YAG陶瓷作为增益介质、半导体可饱和吸收镜(SESAM)作为锁模元件,优化设计了W型谐振腔。在泵浦功率为11.49 W时,获得了波长为1.06μm、重复频率为144 MHz和输出平均功率为1.25 W的稳定连续锁模激光,锁模激光的脉冲宽度为33.6 ps,单脉冲能量为8.7 nJ,峰值功率为0.26 kW。实验结果表明:Nd:YAG陶瓷作为增益介质,可应用于被动锁模超快皮秒激光器中。

准连续波泵浦Yb∶KYW/Cr^(4+)∶YAG调Q激光脉冲产生特性的研究

从被动调Q速率方程出发,理论上研究了准连续波激光二极管(LD)泵浦Yb∶KYW/Cr^(4+)∶YAG激光器时泵浦参数对脉冲输出特性的影响,通过数值计算解析了调Q脉冲延时、脉冲宽度、子脉冲序列等特性与泵浦速率的关系,从而获得最优化泵浦光占空比,有效减少连续波泵浦产生的热效应。进一步,在实验上采用高重频LD泵浦源,通过调控泵浦参数实现了被动调Q激光的重复频率、脉冲延时、脉冲串子脉冲个数等输出特征的准确锁定和控制。当采用泵浦功率为15.6 W、占空比分别为6.50%、8.00%和9.65%时,获得单脉冲、双脉冲和三脉冲的稳定输出,提高了泵浦脉冲和激光脉冲的耦合共振,实验结果与理论计算吻合较好。

脉冲抽运被动调Q激光器脉冲间隔特性研究

采用数值模拟和实验相结合的方法对脉冲激光二极管(LD)抽运Nd:YAG被动调Q激光器输出脉冲间隔特性进行分析。从被动调Q速率方程出发,结合脉冲LD抽运的特点,考虑剩余反转粒子数密度的影响,推导出输出调Q脉冲间隔时间的计算公式。重点分析了抽运脉宽、输出镜反射率、抽运功率和Cr4+:YAG初始透射率对输出脉冲间隔时间的影响。结果表明,数值模拟与实验结果基本吻合。