排序方式: 共有88条查询结果,搜索用时 265 毫秒
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飞秒脉冲时空变换整形技术 总被引:2,自引:2,他引:2
飞秒激光脉冲通过时空变换技术将时域信息变换到空域,通过空域的处理再返回到时域,是实现飞秒激光脉冲整形、测量和控制的一项重要技术。在应用方面,可产生各种所需要的波形.已广泛应用在飞秒化学、信号处理、安全通信、生物学和医学成像等方面。介绍了飞秒时空变换脉冲整形的几种方法。 相似文献
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A simple modal analysis (MA) method to explain the diffraction process of 0th order nulled phase mask is presented. In MA, multiple reflections of the grating modes at grating interfaces are considered by introducing equivalent Fresnel coefficients. Analytical expressions of the diffraction efficiencies and modal guidelines for the 0th order hulled phase grating design are also presented. The phase mask structure, which comprises a high-index contrast HfO2 grating and a fused-silica substrate, is optimized using rigorous coupled-wave analysis around the 800-nm wavelength, after which the modal guideline for cancellation of the 0th order in a phase mask is verified. The proposed MA method illustrates the inherent physical mechanism of multiple reflections of the grating modes in the diffraction process, which can help to analyze and design both low-contrast and high-contrast gratings. 相似文献
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飞秒激光加工微光学元件的研究 总被引:7,自引:0,他引:7
利用低功率飞秒激光振荡器进行材料表面加工的研究并将其应用于微光学元件的加工制作领域;对飞秒激光倍频光以及飞秒激光与光刻胶材料相互作用进行了实验;以光刻胶作为牺牲层进行表面加工获得了各种玻璃光栅及光掩模板;利用光学显微镜和原子力显微镜(AFM)对实验结果进行检测,得到微米量级的特征线宽;所得光栅的光学性能通过He-Ne激光器进行检测,实验结果与理论值一致。该研究为微光学元件的加工制作提供了新的方法。 相似文献
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现有的飞秒脉冲测量理论是建立在简化的脉冲模型基础上,即只对脉冲的时间特性进行测量,不考虑其空间特性.在实际中脉冲的空间特性和时间特性是相互依赖的,即使在自由空间传播的飞秒脉冲它的时间和空间特性之间也发生着相互的耦合作用.文中提出了飞秒激光脉冲测量理论中的时间-空间耦合脉冲模型.考虑到时间和空间之间的耦合作用,飞秒脉冲模型除了包含时间参量之外,还包含空间参量,即脉冲电场的表达式由E(t)变为E(x,y,z,t),给出了时间-空间耦合模型下的脉冲再现迭代算法.这一理论对飞秒脉冲的测量有重要的指导意义. 相似文献
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Nd-doped phosphate glass is the dominant amplifier material used in solid state high average power laser systems.Surface imperfection and subsurface damage(SSD)of the glass,resulting from the optical fabrica-tion process,limit the increment of laser system energy output.Thus,it is important to enhance the surface damage threshold of Nd-doped phosphate glass surface.The influence of abrasive size,polishing powder,grinding mode,and chemical treatment on the laser-induced damage threshold(LIDT)of Nd-doped phos-phate glass surface is investigated.Results show that the LIDT is affected little by different polishing powders and grinding modes.The LIDT correlates with the abrasive size,which produced different depths of SSD.A suitable acid etching treatment can remove the imperfection and the SSD for improving the LIDT of Nd-doped phosphate glass surface.The combination of several effective techniques and methods,which are low-cost and practical,should be useful to enhance the LIDT of Nd-doped phosphate glass surface. 相似文献
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提出了横电、横磁偏振布拉格角入射下光栅模式的色散方程可进一步分解的理论,证明了分解得到的方程与光栅模式对称性间的等价关系。光栅模式的对称性有助于阐释光栅内部衍射过程的物理图像。通过讨论光栅模式方程的根的分布性质,提出了一种提高有效折射率计算效率的方法。 相似文献