共查询到20条相似文献,搜索用时 863 毫秒
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基于建立的纳秒脉冲激光与金属铝相互作用的二维轴对称模型,仿真研究了光束整形对纳秒脉冲激光烧蚀金属铝过程中蒸发烧蚀动力学的影响.结果表明:等离子体屏蔽对靶材的烧蚀特性具有显著影响,屏蔽效应主要体现在脉冲的中后期.对于3种激光轮廓,高斯光束的屏蔽效果最强,随着整形后的平顶光束直径的增大,屏蔽效果逐渐减弱.平顶光束与高斯光束作用下,靶材温度的二维空间分布较为不同.高斯光束作用时,靶材中心最先升温,随后温度沿径向和轴向扩散.由于平顶光束的能量分布更加均匀,因此一定径向范围内的靶材同时升温.光束整形对靶材的蒸发烧蚀动力学影响较大.对于高斯光束,靶材中心先烧蚀,随后产生径向烧蚀.由于整形后平顶光束的能量密度降低,因此靶面蒸发时间较高斯光束延后,并且一定径向范围内的靶材同时发生蒸发烧蚀.3种激光轮廓下,靶材的蒸发烧蚀形貌与光束的强度分布类似,其中高斯光束的烧蚀坑呈中间深两边浅的特点,平顶光束的烧蚀坑较为平坦. 相似文献
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文章提出一种横向激发的任意线偏振高斯光束,该光束场量的模与传统的任意线偏振高斯光束具有相同的模,在源场区,其满足自由空间无源场的场方程。同时利用瑞利—索末菲衍射积分对该高斯光束的非傍轴传输特性进行了解析研究,给出了空间光强分布、束腰和远场发散角的解析通式,发现该类光束的远场光强呈一平顶空心光束。 相似文献
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This paper studies the method of automatic optimization design of Gaussian beam shaping. Firstly, the principle of Gaussian beam shaping was studied theoretically and the flattened Lorentzian function (FL) is chosen as the distribution of flattened beam. The mapping function of arbitrary ray in incident plane and image plane was deduced based on the law of conservation of energy. And then, according to the characteristics of this system, Zemax programming language (ZPL) was used to compile ZPL macro orders to optimize the Gaussian beam shaping automatically. Finally, optical analyzing software was used to test the aspheric lens system. The method is not only simple but also practical with high efficient energy conversion and significant engineering application value. 相似文献
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A method for a beam shaping optics is proposed to convert a laser beam profile into arbitrary required intensity distribution.
Surface profile of the beam shaping optics is designed by using Snell's law to convert the required intensity distribution
at the beam irradiation plane from the input intensity distribution. A computerized numerical control (CNC) lathe is employed
to fabricate the beam shaping optics, and acrylic resin is used for the material. The acrylic resin plate is cut by a ball
type of grinding wheel tool consisted on diamond powder and polished by a cone type felt buff with alumina ceramics powder.
The CNC lathe is powerful tool to control the position of these tools. The fabricated beam shaping optics is aspheric shape
with 4 mm of thickness and it works to convert the intensity distribution of multi-mode beam profile with 13 mm of diameter
into a flat top cylinder with 1 mm of diameter. A working distance of the beam shaping optics is 60 mm, and its transmittance
is over 98%. It succeeds to fabricate uniform melting mark of 0.6 mm diameter on a steel target by the YAG laser process. 相似文献
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A light pipe based laser beam shaper is proposed as a low loss approach to transfer a Gaussian laser beam into a long line
beam with uniform distribution along the line direction for the applications of illumination or material processing. A telecentric
relay optics has been used for solving the radiometric issues in the wide angle optics. In addition, the length of the light
pipe is used as a parameter for manipulating irradiance distribution at the outlet to compensate for the non-uniformity resulting
from the partial reflection at the optical interface in the relay optics, so as to achieve a highly uniform line beam at the
target plane. The proposed scheme provides an economical and versatile solution for the wide angle beam shaping problem. 相似文献
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实验研究了平顶激光光束经微透镜阵列在熔融石英中成丝的演化以及超连续辐射的产生,并进一步与高斯光束的成丝和超连续辐射进行了对比研究.分别对这两种光束的多丝传输进行了横向和纵向成像.结果表明,使用平顶光束可以获得更为均匀的多丝分布,成丝的起点也更为一致;尤其重要的是,相对于高斯光束,平顶光束可以使用更高的入射激光脉冲能量而不会造成介质的损伤,从而可以获得更高脉冲能量和更高转换效率的超连续辐射. 相似文献
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利用双折射透镜组实现激光束空间整形 总被引:2,自引:0,他引:2
为了提高惯性约束聚变高功率激光系统的整体效率和充分利用光能,需要将高斯分布的光束整形为空间均匀分布的平顶光束。本文从球面透镜的琼斯矩阵出发,利用光学传输矩阵对双折射透镜组空间光束整形系统进行了理论分析,数值模拟了整形效果,讨论了透镜组参量的选择以及中心加工厚度误差等因素带来的影响,并对该系统进行了实验研究。在实验中,利用该双折射透镜组整型系统实现了光束的均匀化输出。在神光Ⅱ第九路中,在近场静态工作条件下,可将光束填充因子从原来的66%提高到80%。 相似文献
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任意形状凸粗糙物体高斯光束相干散射研究 总被引:4,自引:3,他引:1
研究了任意形状凸粗糙物体对高斯光束的相干散射特性。由平面波谱展开法推导出粗糙面高斯波束散射场表达式.并根据物理光学近似和稳相法原理得到相干散射截面的理论公式。与平面波解不同的是,在公式中引入了波束因子这一表征波束作用的重要参量,该参量与束腰半径、束腰中心与物体中心距离和物体照射面积以及入射、散射方向有关。最后数值计算了1.06μm激光波束对粗糙球的散射,分析了波束因子.介电常量和极化状态对红外激光相干散射截面的影响,重点讨论了波束因子的变化规律。分析表明.当波束半径远大于物体尺寸时,波束入射的结果可退化到平面波情况。 相似文献
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Analysis of factors affecting beam shaping quality of geometric steady-phase method based on SLM北大核心 下载免费PDF全文
基于几何稳相法求解调制相位,使用傅里叶透镜进行傅里叶变换,在后焦面处聚焦,得到对应的平顶光束,从而将圆形高斯光束整形为方形平顶光束,其中光路参数对整形质量将产生较大影响。实验中发现,方形平顶光束受零级光影响均匀性较差,因此详细分析了零级光产生的原因,提出了有效的解决方法,并对实验结果中出现的零级光通过叠加闪耀光栅直接移除。实验结果表明:移除零级光后方形平顶光束的能量利用率为72.3%,光束均匀性高达97.2%,优于传统整形方法。最后进一步分析了全息图与入射光束偏移量、离焦以及入射光束束腰半径对几何稳相法整形质量的影响,为几何法光束整形的应用提供了便利。 相似文献