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Output beam drift and deformation in high-power COIL 总被引:1,自引:0,他引:1
During the operation of a chemical oxygen iodine laser (COIL) with an unstable resonator of a large Fresnel number, as the output power increases, an instability of the output laser beam will appear, behaving mainly as far-field beam spot drift and deformation. In order to interpret this phenomenon, thermal expansion analysis on the scraper with finite element analysis method and a simulation of the output beam mode of this kind of laser by the method of Fast Fourier Transform were developed. From the experimental measurement and the calculation, we proposed that the presence of the nonuniform temperature distribution of scraper causes the front surface of the scraper to tilt and bulge due to thermal expansion. As the output power is increasing, all the mirror surfaces, especially the scraper's, will absorb more and more heat, causing thermal expansion of the mirror front surface to occur more seriously, thus resulting in the tilting and deformation of the far-field beam spot. The initial misalignment of the direction is also an important factor leading to the far-field beam spot drift and deformation. 相似文献
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为了获得高功率激光束,提出利用双色镜对典型波长2种不同类型(脉冲、连续)的高能激光进行合束,以实现高功率高能量激光输出。通过对双色镜的热效应和合束光斑远场激光参数进行仿真分析计算,热效应仿真结果表明,在单束激光10 kW、光斑直径15 mm条件下,双色镜面型热形变量均方根值为0.004λ(λ=632.8 nm),满足光学元件面型小于0.03λ精度要求。搭建了一套基于双色镜的光谱合束系统,并分别进行了高功率连续激光与高功率连续激光、高功率连续激光与高能量脉冲激光的合束试验,合束效率高于95%。试验结果表明,光谱合束可有效应用于高能激光领域。 相似文献
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通过等效净吸收功率密度方法获取了强激光反射镜热畸变的干涉图像,提出了热畸变反射镜在平面波照射下近场波面畸变与远场光斑的计算方法,探讨了强激光远场光斑测试的一种新思路。定量分析结果表明,对单晶硅镜,在净吸收功率210W,光照时间为6s时,最大热畸变达到0.76μm,由此造成的近场波面Zernike离焦系数为0.32μm,x方向和y方向彗差分别为0.13μm和0.22μm, x方向倾斜系数上升到0.12μm,光束质量因子达5.7。 相似文献
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为简化高功率激光器谐振腔结构,提高激光谐振腔的稳定性,增加基模体积,改善光束质量,提出了两种新型激光谐振腔结构,分别是带角隅反射镜的激光谐振腔和直角内圆锥面反射镜激光谐振腔。使用高功率脉冲CO2激光器,研究了这两种激光谐振腔的输出特性和腔镜失调的关系,并结合平凹稳定腔,对三种激光谐振腔的抗失调稳定性进行了对比。实验结果表明,随着全反镜或平面输出镜失调角的增加,角隅腔激光器的单脉冲输出能量下降速度小于直角内圆锥面全反镜腔。两种新型谐振腔全反镜的抗失调稳定性都超过平面输出镜。角隅全反镜谐振腔和直角内圆锥面全反镜谐振腔的抗失调稳定性均大大超过平凹稳定腔。 相似文献
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HONG Zhi CHEN Jun 《Chinese Journal of Lasers》2001,10(6):401-405
1 Introduction SemiconductorlaserarrayshavereachedhighoutputpowerofseveralWincontinuous waveoperation[1] ,butduetothepoorspatialcoherenceandbeam profile ,applicationsarelimited .Inordertoenhancethespatialcoherence,thenumberoftransversemodesmustbereduced ,w… 相似文献
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Abstract An external cavity for the laser diode array with a conventional mirror in what we call two-time self-injection operation is presented. The external cavity consists of two lenses, a flat external mirror(EM) in the image plane of the array and a prism that is used as an output coupler. The single-lobed near diffraction-limited far field beam of a 1 W 10-stripe gain-guided LD array lies at 6.4°~9° with the external cavity operation in two-time self-injection mode, whereas at 2.5°~3.0° for its normal feedback operation. The width of the far field beam (FWHM) is 0.43° and 0.63° at driving current of 2 and 3.2 ×Ithr, respectively, much narrower than that in normal feedback operation, but at the expense of lower output power. The output of the system is very stable and insensitive to the tilt and position of the EM. 相似文献
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针对激光光斑漂移设计了一套光斑漂移检测系统。利用该系统实现了对He-Ne激光器出射光束漂移的检测。它采用CCD摄像头和图像采集卡采集激光器输出光斑,通过专门软件对数字图像进行处理,得出光斑漂移的大小;另外,利用几何光学方法得到了激光光束在X方向、Y方向以及空间立体角上的漂移大小。分析了引起光束漂移的原因。结果表明:He-Ne激光器出射光束的指向主要受温度、环境振动、空气扰动和激光器自身结构的影响。该系统能准确地测量出激光器出射光束的漂移大小,实现光束漂移的控制。 相似文献
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A hybrid metallic mesh multilayer dielectric coating mirror has been developed for use as an output mirror for optically pumped far infrared lasers. The metallic mesh provides a high reflectance in the far infrared while the multilayer dielectric coating is chosen to provide a maximum reflectivity at the pump wavelength (10 μm). This hybrid mirror has increased the output power of a CH3F waveguide laser at 496 μm by a factor of 350 over that obtained with a hole coupling mirror. In addition, this mirror results in a far infrared output beam which has a minimum angular divergence limited only by the particular oscillating transverse waveguide mode (the EH11 mode for this experiment). 相似文献
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圆形高斯镜平凹腔腔镜变形时激光模场分析 总被引:3,自引:2,他引:1
把圆形高斯镜平凹腔自再现模的衍射积分方程转化为有限阶的矩阵方程,在平面输出镜呈高斯分布的镜面变形时,数值计算了激光场模式的场强、相位分布和模式本征值。结果表明,当变形量较小时,随着变形量的增加,镜面上光场的分布范围增大,也就说明模体积增大,但镜面光场仍保持拉盖尔-高斯光束基模特征,相位由平面慢慢变得凸起,远场分布变化不明显。当变形量较大时,光场分布开始发生畸变。从模式本征值的变化看,在一定的变形范围内,本征值下降不多,说明较小的变形量对激光损耗影响不大,仍能使激光较稳定输出。在圆形高斯镜平凹腔输出镜发生不大的高斯状变形的情况下,仍有维持输出高质量激光束的能力。 相似文献
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发现和分析了氧碘化学激光中的增益光导效应。碘注入的不均匀等导致增益在该方向的不均匀。采用预混模型和Fabry Perot腔模型,推导了碘不均匀分布情况下的单重态氧的产额和激光束横向分布的解析表达式。计算结果表明,由于增益光导效应,引起激光横向分布的变化,可导致光束在碘注入方向的倾斜,以及输出功率的下降。 相似文献
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Periodic adjustment of the position of a laser beam spot on a semiconductor saturable absorber mirror in a passively mode-locked solid-state laser 下载免费PDF全文
A laser diode end-pumped passively mode-locked Nd:YVO4 solid-state laser with a semiconductor saturable absorber mirror (SESAM), in which the intracavity laser beam spot on the SESAM can be adjusted periodically, is investigated. Inserting a rectangular prism (RP) into the laser cavity is a promising approach towards the goal of periodically moving the position of the focus spot of the intracavity pulse on the SESAM surface to avoid the long-time irradiation of the laser beam on the same position, thereby solving a series of problems caused by damage to the SESAM and greatly prolonging its usage life. The adjustment of the rectangular prism in the laser cavity does not break the stable continuous wave (CW) mode-locked condition. The laser generates a stable picosecond pulse sequence at 1064 nm with an output power of 3.6 W and a pulse width of 14 ps. The instabilities of the output power and the pulse width are 1.77% and 4.5%, respectively. 相似文献
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输出环状光束的新型激光谐振腔 总被引:3,自引:0,他引:3
提出一种输出环状光束的新型激光谐振腔,即在稳定激光谐振腔中采用外环耦合方式得到环状光束的输出。利用For-Li数值迭代算法求解此类激光谐振腔的积分方程,通过计算机编程计算了平面一凹球面稳定谐振腔的输出端平面镜在不同半径的情况下,谐振腔镜面上和衍射耦合输出场基模的振幅和相位分布。计算结果预示了当输出端平面镜半径小于通常的稳定腔的基模半径时,衍射耦合输出场有稳定的环状光束输出。实验中TEA CO2激光器采用印刷电路板预电离结构,增益长度90cm,腔长5m,球面全反射镜曲率半径20m,输出端平面镜半径4.5mm,得到了内环半径为4.5mm、外环半径为5.5mm的基模环形光斑输出。从而在理论上和实验上证实了该方案产生环状光束的可行性。 相似文献