高光学质量,高平均功率非稳腔Nd：YAG激光器

在分析含热透镜的非稳腔固体激光器普遍特性的基础上，分别定义了几何放大率和输出曲率半径的热敏感度，结合腔镜失调敏感度而成为设计该类谐振腔的重要依据，据此，进一步改善和发展的新型的棒成像非稳腔。     

高斯反射率输出镜改善光束质量的实验研究

非稳腔能产生大体积基模,具有好的空间选模特性,但在固体调Q激光器中,由于孔径光阑和热畸变的影响,非稳腔输出的横模并不光滑.使用高斯反射率耦合输出镜可较好地改善其输出光束质量,设计了平-凸非稳腔,使用Nd:YAG,电光调Q固体激光器进行实验,获得了较为平滑的远场光强分布,实验结果表明高斯反射率输出镜可较好地改善固体激光器中非稳腔输出光束质量.     

连续波DF化学激光器光斑上下游光谱测量

通过分析非稳腔DF化学激光器光腔内激光路径特性,指出非稳腔DF化学激光器输出光斑上下游光谱振荡路径不同导致输出光谱存在一定差异。试验测量了一台连续波DF化学激光器光斑上下游光谱,结果表明:非稳腔DF化学激光器光斑上下游光谱主要谱线成分未见显著差异;光斑上下游谱线相对强度存在一定差异;光斑上游各谱带相对强度最大值谱线转动量子数趋向于各谱带低转动量子数方向。根据实测光谱,对光斑上下游光谱所表征光腔温度和相对粒子数范围进行了估算,得到光腔上游平均温度要低于光腔下游平均温度。     

交叉棱镜腔Nd:YAG板条激光器

对稳定和非稳共焦型Nd:YAG板条激光器的特性作了理论分析和实验研究.证实了使用交叉棱镜腔的流动空气-水混合冷却板条激光器有高的光束质量和对棱镜失调的不灵敏性,可望获得某些实际应用.关键词:交叉棱镜腔,板条激光器.     

硬边非稳腔平面波导激光器的光束特性

基于衍射理论和坐标变换,采用数值模拟的方法分析了硬边非稳腔平面波导激光器的光束特性,研究了存在非均匀抽运和增益饱和时,输出激光的光束质量.在端面抽运和边缘抽运时,比较了正支和负支非稳腔的输出光束特性.结果表明:利用优化的离轴硬边非稳腔可以得到近衍射极限的输出.在相同的抽运不均匀性情况下,对于边缘抽运和端面抽运,正支非稳腔的光束质量因子M2分别为3.9和2.3,而相同条件下负支非稳腔的M2因子为1.8和1.7.     

球面角锥棱镜非稳腔钕玻璃激光器

为了将虚共焦非稳腔输出光束质量高和角锥棱镜谐振腔具有免调试的优点结合到一起,提出了用球面角锥棱镜构成虚共焦非稳腔的方案。利用已有虚共焦非稳腔钕玻璃激光器,设计加工了一球面角锥棱镜非稳腔钕玻璃激光器。模拟计算了两谐振腔输出光束的模式分布,然后对两钕玻璃激光器进行了实验对比研究。结果表明:实验得到的模式分布与模拟计算结果相吻合,球面角锥棱镜非稳腔钕玻璃激光器与虚共焦非稳腔钕玻璃激光器分别获得了最大2176.9J和2340.6J的能量输出,二者的电光效率与束散基本相同,分别为4.3%,0.30mrad和4.6%,0.26mrad。     

多棒串接固体激光器谐振腔的研究

运用矩阵光学的方法对多棒串接固体激光器的谐振腔参数及其在平平腔时的热稳条件进行了研究，并计算了六棒串接平平腔固体激光器的稳定区.结果证明：多棒串接固体激光器的稳定区和非稳区相互间隔，在平平腔总腔长、激光棒数量n和棒间距L一定的条件下，当采用对称结构时(L₁=L₂)，则谐振腔的每段稳定区均达到最大；且只要 平平腔满足L₁=L₂=L/2以及热焦距f在大于某个下限值f_m时，稳定性条件01< 关键词： 多棒串接固体激光器 稳定区 热稳条件     

非稳腔输出环状激光束的传输特性

本文从菲涅耳衍射积分公式出发研究了激光器非稳腔输出环状光束在空间的传输规律.由轴上光强的极值点位置给出了划分非稳腔传输空间的近场、中场和远场区域公式.理论计算结果表明,非稳腔输出端环状光束在中场区域激光能量逐渐向轴心方向转移,而在远场变为爱里型圆盘状光束的过程.在非稳腔脉冲TEA CO_2激光器上测得的实验结果与理论计算结果很好地符合.     

大功率TEA CO2激光器非稳腔的设计与实验

相比于传统稳腔高功率TEA CO2激光器,如何在不降低功率的基础上,改善其光束质量一直研究者关心的问题。本文在原有稳腔激光器的基础上,设计了三组望远镜虚共焦腔镜,给出了完整的设计过程并进行了理论分析。同时对不同组的非稳腔激光器进行了对比实验研究,结果表明非稳腔能够在保证高单脉冲能量的基础上极大地改善激光远场发散角,其中最佳腔镜组合能够达到单脉冲能量13.7J,其发散角为1mrad（稳腔为2.4mrad）,激光脉宽50ns（稳腔为98ns）。这就为此种类型激光器应用于激光制造领域奠定了基础。     

用薄层处理法模拟有源共焦非稳

 采用FFT方法和增益介质近腔镜簿层处理法研究了非稳腔下具有非均匀流动介质的高功率气体激光器的光束特性和光束质量,证实了该方法在小扰动、低放大率、低增益器件的腔型中是适用的。     

高效全固化紫外四倍频激光器的研究

用半导体激光器抽运的调Q YLF倍频激光器抽运掺钛蓝宝石激光器，用LBO晶体在腔内产生二次谐波，再聚焦到BBO晶体上产生四次谐波深紫外激光。为了提高谐波转换效率，在腔内分别插入了单片、组合双折射滤光片和聚焦透镜，在平均功率为3.6W，波长为527nm的抽运光下得到410mW，417nm的蓝光。用长焦距的透镜聚焦二次谐波，得到34mW，208nm的紫外脉冲激光。从实验上详细研究了基频光的线宽对二次谐波效率的影响，二次谐波的线宽对四次谐波效率的影响、基频光的波长对四次谐波产生效率的影响。全面地分析了单片和组合大拆射滤光片及抽运功率对钛蓝宝石激光器基频光的脉宽、线宽等参量的影响。     

A diode-pumped linear intracavity frequency doubled Nd:YAG rod laser with 40 ns pulse width and 73 W green output power

We analyzed a linear cavity for intracavity frequency doubling of a diode-pumped acousto-optic Q-switched Nd:YAG rod laser, and showed that a green laser beam with a short pulse width can be generated efficiently. A green laser output power of 73 W corresponding to the 83.9% of maximum IR output power was obtained with a 40 ns pulse width at a 10 kHz repetition rate. A green output power of 40 W with a 35 ns pulse width was measured at a 5 kHz repetition rate. Minimum laser pulse width of approximately 32 ns was obtained around 1 kHz repetition rate for both green and IR laser beams.     

Theoretical and experimental investigations of quasi-continuous wave diode array side-pumped Yb＇YAG slab laser

An analytical model of quasi-continuous wave (quasi-CW) diode array side-pumped slab laser for Yb:YAG oscillator in long-pulse free-running has been developed based on the CW model. In this model we first introduce a new parameter, pump pulse width, and make the model available for use in the quasi-CW model. We also give an analytical equation of laser delay time to calculate the laser pulse width. A detailed model is also presented for a new structure laser design, taking account of the geometry of Yb:YAG slab. A quasi-CW diode array side-pumped Yb:YAG slab laser is investigated theoretically and experimentally. Experiments yield a quasi-CW output energy up to 20.36 mJ with the laser pulse width of 654.55 μs at 1049 nm when the diode arrays operate at 25 Hz and 1 ms pulse width. The crystal dimensions are 3 mm×8 mm×1 mm and the doping density is 10 at.%. The experimental results are in good agreement with the predictions of the theoretical model.     

脉冲单频Nd:YVO4激光器及其倍频输出特性研究

为了研制激光干涉成像所需的主振荡功率放大(MOPA)结构脉冲单频激光器,本文完成MOPA激光器的种子源即声光调Q脉冲单频1 064 nm激光器的特性研究,同时完成种子源腔外倍频绿光特性研究。脉冲单频激光器采用声光调Q模块实现脉宽约20 ns的1 064 nm脉冲激光输出,采用环形腔设计并采用一组不同厚度的标准具实现单纵模运转。实验研究基频1 064nm和倍频532 nm激光脉冲的线宽,得出在全脉宽范围内都具有较高时间相干性的结论。实验分别获得脉宽约28 ns峰值功率约6.5 kW的1 064 nm脉冲单频激光和脉宽约20 ns、峰值功率约0.5 kW的532 nm脉冲单频激光,腔外倍频效率为5.6%。实验同时也验证了腔外倍频的激光脉宽压缩效应。     

高重复频率LD端面抽运声光调Q腔内倍频绿光激光器

利用LD端面抽运声光调Q Nd∶YVO4激光器作为抽运源,采用线性腔实现了KTP腔内倍频高效绿光激光的输出.在调Q脉冲重复频率为40 kHz、1 064 nm输入光的功率为1 608 mW的条件下,获得了999 mW单横模（TEM00模）的绿光输出,相应的光-光转换效率为62.1%.绿光激光器输出光谱的半峰宽小于0.11 nm,其输出功率的不稳定度为±1.2%.     

斩波法在激光微能量计标定中的应用

针对激光微能量测量的问题,提出一种激光微能量计标定新方法与装置。研究内容包括使用稳功率连续激光作为光源,通过基于斩波的脉冲发生器组件产生微能量的脉冲激光,分别使用脉冲宽度测量组件与功率测量组件进行采集、软件分析,计算微能量值及通过比对给出待标定能量计的修正系数,计算机自动控制。结果表明,该方法获得的脉冲激光波形稳定,脉冲宽度测量不确定度为0.08%,激光功率测量不确定度为0.25%,实现了对0.1 pJ～1 mJ的激光能量进行准确复现和传递。     

新型非临界相位匹配KTA-OPO 2 μm激光器

首次提出了一种基于非临界相位匹配KTA光参量振荡的新型2 m脉冲激光技术。采用激光二极管(LD)端面泵浦Nd:YVO4晶体实现1.3 m振荡,腔内泵浦非临界相位匹配切割的KTA晶体,初步实现了超过1 W的2.1 m波段激光输出,光光转化效率10%,脉宽3.4 ns (30 kHz)。相对于其他方式获得的2 m波段激光,具有脉宽窄、峰值高、谱线纯等优点,是一种获得2 m波段激光的有效新途径。     

High-power near diffraction-limited 1 064-nm Nd:YAG rod laser and second harmonic generation by intracavity-frequency-doubling

We present a near diffraction-limited 1 064-nm Nd:YAG rod laser with output power of 82.3 W(M~2≈1.38). The power fluctuation over two hours is better than±1.1%.Pulsed 1064-nm laser with an average power of 66.6 W and pulse width of 46 ns are achieved when the laser is Q-switched at a repetition rate of 10 kHz.The short pulse duration stems from the short cavity as well as the high-gain laser modules. Using intracavity-frequency-doubling,a 35.0-W near diffraction-limited 532-nm green laser(M~2≈1.32) is achieved with a pulse width of 43 ns.     

Acousto-optic Q-switched self-frequency-doubling Er:Yb:YAl3(BO3)4 laser at 800 nm

Actively Q-switched self-frequency-doubling laser at 800 nm was first reported in an Er:Yb:YAl3(BO3)4 crystal by using an acousto-optical modulator. At incident pump power of 16 W and pulse repetition frequency of 1 kHz, 1600 nm fundamental pulse laser with energy of 130 μJ and width of 170 ns, and self-frequency-doubling 800 nm pulse laser with energy of 20 μJ and width of 96 ns were respectively achieved in a hemispherical resonator end-pumped by a 970 nm laser diode. Pulse characteristics of fundamental and self-frequency-doubling lasers at different pulse repetition frequencies were also investigated.     

YAG laser percussion drilling of a functional multi-layer thin plate

An Au-coated Fe–Ni alloy thin plate was laser drilled by a pulsed Nd:YAG laser. The influences of laser parameters on the diameter of perforation, the outer diameter of crater and the roundness of the perforation have been investigated by employing scanning electron microscopy. The diameter of perforation increases gradually with an increase in pulse width from 0.3 to 8 ms at the fixed average laser power and frequency, and increases with an increase in average laser power from 10 to 25 W at the fixed pulse width and frequency. Some craters are found around the perforations because of the heat affecting of laser beam to the non-irradiated zone. The diametric difference of the perforation between the incident and the effluent sides is very small under the shortest pulse width of 0.3 ms. Good roundness of the perforation can be achieved at either the lowest pulse width or the lowest laser power.