热退偏损耗完全补偿的千赫兹电光调QNd:YAG激光器

为了同时补偿固体增益介质的热致双折射及热透镜效应,进一步提高重复频率1 kHz激光二极管(LD)侧向抽运高平均功率电光调Q Nd:YAG激光器的输出功率,设计了一种完全消除热退偏损耗的双调Q开关谐振腔结构,此结构在传统调Q谐振腔的基础上沿着偏振片的退偏方向增加了一个调Q谐振支路,并使得激光从增益介质方向输出。实验结果表明,此激光器的单脉冲能量比单Q开关结构的非补偿腔输出能量高出74.7%。当侧面抽运的激光二极管输出脉冲能量达到307 mJ时,激光输出能量达到26.2 mJ,光-光转换效率为8.5%,光束发

高重复率窄脉宽Nd∶YVO_4板条激光器

部分端面抽运的混合腔板条激光器是一种新型的全固态激光器,采用这种结构,实现了高重复率调Q运转。在脉冲抽运情况下,1kHz运转时,得到脉宽4.6ns,单脉冲能量4.5mJ的激光输出。在连续抽运调Q输出情况下,5kHz高重复率运转时,获得了脉宽6ns,单脉冲能量3.1mJ的脉冲序列输出,平均功率超过15W;当重复率高达25kHz时,得到脉宽9.5ns,单脉冲能量1.2mJ的激光输出,平均功率达30W。实验结果表明,输出水平还有很大的提升空间。

高重复频率、窄脉宽全固态光纤放大器种子源

高重复频率、窄脉宽的全固态激光器种子源级联光纤放大器是获得高功率脉冲激光输出的有效手段.短上能态寿命的Nd∶YVO4晶体在连续抽运、高重复频率Q开关工作时容易得到接近连续性能的平均输出功率.理论分析了声光(AO)调Q器件中影响输出能量和脉宽大小的主要因素,优化配置了腔型参数.利用激光二极管(LD)光纤耦合模块端面抽运Nd∶YVO4晶体,实现了声-光调Q重复频率100 kHz以上,脉宽20 ns以下,波长1064 nm的激光输出.在抽运功率5.7 W时,得到了脉宽15.3 ns,重复频率150 kHz的种子光输出,在级联单级光纤放大器后,得到了20 W的输出.

传导冷却的全固态zigzag板条激光器

报道了激光二极管泵浦的被动传导冷却的Q开关Nd:YAG zigzag 板条激光器，谐振腔采用平平腔和非稳腔。在20Hz运转时，得到脉宽均为10ns的150 mJ，光光效率19%的多模输出和100 mJ、13%光学效率的单模输出，并进行了相关的热效应测试，结果表明该激光器具有效率高、结构紧凑、光束质量好，在空间环境应用具有很好的发展潜力。

考虑激光下能级弛豫过程的调QNd：YAG速率方程理论分析

本文比较了考虑与不考虑激光下能级弛豫过程的两种形式的调Q速率方程，并以二极管激光侧面泵浦电光调QNd：YAG为例，分别采用两种形式的调Q速率方程，分析了调Q过程中上、下能级粒子数变化过程，计算了输出调Q激光脉冲波形、峰值功率以及能量，进行了比较分析，并解释了调Q“子脉冲”与拖尾现象。

20-W average power, high repetition rate, nanosecond pulse with diffraction limit from an all-fiber MOPA system

In this article, we report an all-fiber master oscillator power amplifier (MOPA) system, which can provide high repetition rate and nanosecond pulse with diffraction-limit. The system was constructed using a (2 + 1) X 1 multimode combiner. The Q-Switched, LD pumped Nd:YVO4 solid-state laser wets used (is master oscillator. The 976-nm fiber-coupled module is used as pump source. A 10-m long China-made Yb3+-doped D-shape double-clad large-mode-area fiber was used as amplifier fiber. The MOPA produced as much as 20-W average power with nanosecond pulse and near diffraction limited. The pulse duration is maintained at about 15 its during 50-175 kHz. The system employs a simple and compact architecture and is therefore suitable for the use in practical applications such as scientific and military airborne LIDAR and imaging. Based oil this system. the amplification performances of. the all fiber amplifier is investigated. (C) 2008 Wiley Periodicals, Inc.

Growth of excellent-quality Nd : LuVO4 single crystal and laser properties

High-quality Nd:LuVO4 single crystal was successfully grown by Czochralski method. The assessment of the crystalline quality by the chemical etching method and Conoscope image was reported. The absorption spectra from 300 to 1000 nm and emission spectra from 960 to 1450 nm of Nd: LuVO4 were measured. Laser performance was achieved with Nd:LUVO4 crystal for the transition of F-4(3/2) -> I-4(11/2) (corresponding wavelength 1065.8 nm) in an actively Q-switched operation, and the average output power reached 5.42 W at a pulse repetition frequency (PRF) of 40 kHz under pump power of 18 W, giving an optical conversion efficiency of 30.1%. The pulse energy and peak power reached 138 mu J and 16.2 kW at PRF of 25 kHz under pump power of 14.2 W, and the pulse duration was 8.5 ns. (c) 2005 Elsevier B.V. All rights reserved.

Characterization of diode-pumped laser operation of a novel Yb : GSO crystal

We report what is believed to be the first demonstration of the laser action of Yb3+ -doped Gd2SiO5 (Yb:GSO) crystal pumped by a 940-nm laser diode at room temperature. The threshold of laser generation is only 0.85 kW/cm(2), which is smaller than the theoretic threshold of Yb:YAG (1.54 kW/cm(2)). The laser wavelength is 1090 mn. With a 2.5% output coupler, the maximum output power is 415 mW under a pump power of 5 W. By using the SESAM, the Q-switched mode locking and CW mode-locked operations are demonstrated.

铬、钕双掺钆镓石榴石（Cr^4＋，Nd^3＋）：Gd3Ga5O12激光晶体光学性能的研究

用提拉法生长了掺铬、钕的钆镓石榴石(Cr^4+，Nd^3+：GGG)自调Q激光品体。报道了室温下的吸收光谱和荧光光谱特性。分析了Cr离子浓度对光谱性质的影响。比较了Cr^4+：GGG，Nd^3+：GGG和(Cr^4+，Nd^3+)：GGG晶体吸收光谱的关系。测量了(Cr^4+，Nd^3+)：GGG晶体和Nd^3+：GGG晶体的荧光寿命，它们分别是33μs和250μs。实验表明，(Cr^4+，Nd^3+)：GGG晶体是一种非常有潜力的自调Q激光晶体，可以实现大功率激光器的小型化和全固态化。

Room-temperature cw and pulsed operation of a diode-end-pumped Tm:YAP laser

We report the continuous-wave and acousto-optical Q-switched operation of a diode-end-pumped Tm:YAP laser. Continuous-wave output power of 3.5 W at 1.99 mu m was obtained under the absorbed pump power of 14 W. Under Q-switched laser operation, the average output power increased from 1.57 W to 2.0 W, with an absorbed pump power of 12.6 W, as the repetition rate increased from 1 kHz to 10 kHz. The maximum Q-switched pulse energy was 1.57 mJ with a repetition rate of 1 kHz. The minimum pulse width was measured to be about 80 ns, corresponding to a peak power of 19.6 kW.

高真空室中的水蒸气对HfO2薄膜性能的影响

本文研究了在镀膜过程中真空室内水蒸气的含量对HfO2薄膜物理性能的影响。用电子束蒸发和光电极值监控的方法在BK7基底上制备HfO2薄膜。利用残余气体分析仪在线监测了真空室内的残余气氛组成。分别用Lambda 900光谱仪、X射线衍射方法、表面热透镜技术和1064nm的激光器测试了薄膜的光学性能、微结构、吸收和激光损伤阈值。实验发现，附加冷阱装置有助于我们有效控制镀膜过程中的水汽含量，且在水蒸气含量较少的真空室内镀制的薄膜具有较高的折射率，较小的晶粒尺寸，较低的弱吸收值和较高的损伤阈值。

A Diode-Side-Pumped Dynamic Fundamental Mode Nd:YAG Laser

A fundamental mode Nd YAG laser is experimentally demonstrated with a stagger pumped laser module and a special resonator. The rod is pumped symmetrically by staggered bar modules. A dynamic fundamental mode is achieved with the special resonator under different pump levels. A maximal continuous wave output of 61 W (M-2 = 1.4) is achieved with a single rod. An average output of 47 W, pulse width of 54 ns, pulse energy of 4.7 mJ and peak power of 87 kW are obtained under the Q-switched operation of 10 kHz.

Experimental study of a pulsed ytterbium-doped fibre laser with fast and slow saturable absorbers in a linear cavity

We present a linear-cavity stretched-pulse fibre laser with mode locking by a nonlinear polarization rotation and by semiconductor saturable-absorber mirrors. A Q-switched mode-locking cw train and a mode-locking pulse train are obtained in the experiment. We investigate the effects of the equivalent fast saturable absorber and the slow saturable absorbers in experiment. It is found that neither the nonlinear polarization evolution effect nor a semiconductor saturable absorber mirror is enough to produce the stable cw mode-locking pulses in this experiment. A nonlinear polarization evolution effect controls the cavity loss to literally carve the pulses; semiconductor saturable absorber mirrors provide the self-restarting and maintain the stability of the mode-locking operation.

Experimental and theoretical analysis of nondegenerate ultrabroadband chirped pulse optical parametric amplification

Experimental investigations of nondegenerate ultrabroadband chirped pulse optical parametric amplification have been carried out. The general mathematical expressions for evaluating parametric bandwidth, gain and gain bandwidth for arbitrary three-wave mixing parametric amplifiers are presented. In our experiments, a type-I noncollinear phase-matched optical parametric amplifier based on lithium triborate, which was pumped by a 5-ns second harmonic pulses from a Q-switched Nd:YAG operating at 10 Hz, seeded by a 14-fs Ti:sapphire laser at 800 nm, was presented. The 0.85 nJ energy of input chirped signal pulse with 57-FWHM has been amplified to 3.1 muJ at pump intensity 3 GW/cm(2), the corresponding parametric gain reached 3.6 x 10(3), the 53 nm-FWHM gain spectrum bandwidth of output signal has been obtained. The large gain and broad gain bandwidth, which have been confirmed experimentally, provide great potentials to amplify efficiently the broad bandwidth femtosecond light pulses to generate new extremes in power, intensity, and pulse duration using optical parametric chirped pulse amplifiers pumped by powerful nanosecond systems.