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温度涨落和波长偏离对衍射透镜性能的影响 总被引:1,自引:1,他引:0
根据菲涅耳衍射透镜的特点,阐明了温度色散和波长色散的概念,并建立了相应的数学表达式,给出了衍射效率与温度和波长的关系式,在此基础上做了较为全面系统的理论和数值分析,评估了温度场发生变化以及使用波长和设计波长发生偏离对衍射透镜性能的影响程度.结果表明:波长偏离对衍射透镜性能的影响要比温度涨落明显得多,其中,波长色散具有非线性特征. 相似文献
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用二维时域有限差分法分析条形多层波导 总被引:1,自引:0,他引:1
为精确分析条形多层波导和多量子阱波导,本文提出了一种以二维时 限差分法为基础的全波数值方法,给出了场分布的色散特性的数值结果,并与矢量有限元法已有的结果作了比较;文中还研究了以二维时域有限差分法为基础的标量近似技术,提出了它的有效性和精度的局限性。 相似文献
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使用时域有限差分法,研究了各向异性特异材料(AMM)作为包层的AMM/介质/AMM波导中表面等离子体的共振性质.色散关系表明,当特异材料为负磁导率的always-cutoff型时,AMM/介质/AMM波导支持TE极化的表面等离子体,表面等离子体的波长随着中间介质层的厚度和特异材料磁等离子体频率的减小而变短.在有限长度AMM/介质/AMM波导中,由于两端界面的反射,表面等离子体模在波导中形成Fabry-Perot共振,而实现亚波长的表面等离子体微腔.在共振频率,电场强度在微腔的中部达到最大值,而磁场分别在两端界面处达到最大,电磁能强局域在中间介质层中,这一性质将在可调的具有强局域特性的亚波长微腔及腔量子电动力学中具有潜在的应用. 相似文献
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多台阶圆形衍射微透镜聚焦性能的矢量分析 总被引:2,自引:0,他引:2
给出了基于旋转体时域有限差分法的严格的矢量分析模型,应用该模型分析了多个多台阶圆形衍射微透镜的设计实例.研究了设计参量和制作误差对其聚焦性能的影响.结果表明增加环带数,但保持其他设计参量例如焦距、入射波长不变时,焦点场强增大、焦斑变小、焦深变短;只增加台阶数时,聚光作用加强,但台阶数达到8~10后,聚焦效果趋向稳定,因此建议在实际加工中,台阶数选择8~10.用二元掩模板套刻制作多台阶时,容易产生制作误差.设计了在第三次套刻制成8个台阶过程中产生了对准误差和系统刻蚀误差的两类多台阶微透镜.分析结果表明对准误差对多台阶微透镜聚焦效果的影响较大,加工时要尽量避免,而系统刻蚀误差对多台阶微透镜聚焦效果的影响较小. 相似文献
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Yuling Liu Hua Liu Liangfang He Hanqing Zhou Chenghua Sui 《Optics & Laser Technology》2010,42(8):1286-1293
The broadband dispersion characteristics of diffractive microlenses are studied using the finite-difference time-domain (FDTD) method. The distributions of the diffracted electric fields obtained through a diffractive microlens are presented for illumination wavelengths ranging from 0.35 to 1.30 μm, along with the corresponding broadband dispersion curves. It is shown that both the principal focal length and the diffracted order of the principal focal point are dependent on the illumination wavelengths. The broadband dispersion characteristics of a diffractive microlens may be used to optimise light coupling for a broadband optical fibre source. 相似文献
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Herein, tunable protein harmonic diffractive microlenses (PHDMs) have been constructed by femtosecond laser direct writing from bovine serum albumin. With excellent three-dimensional topography, PHDMs show distinct harmonic diffractive features, such as similarly good imaging performance with smaller thickness than refractive lenses and well controlled minus chromatic dispersion compared with simple diffractive lenses (~5% focal length shift against ~21% of the protein Fresnel zone plate with the same radius under light with wavelength 450-659 nm). Owing to the nature of protein molecules as "building blocks," the focal length of the PHDM can be facilely tuned within seconds by changing the pH value (focal length tunability of up to ~20%). 相似文献
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阐述SPD-I型全息凹面衍射光栅平场摄谱仪的基本工作原理和仪器结构,详细报导了该仪器的适用波长范围、平直谱面长度、倒数线色散率和光谱带宽等主要技术性能的光学测试方法和实验结果。测量结果表明在设计波长范围(400至800mm)内像差校正良好,获得的平直谱面可与光敏面长度为一英寸(23.5cm)的多通道探测器相配;仪器的色散相当均匀(约17nm/mm),在579.96nm波长处测得的光谱带宽为1nm,能满足一般光学多通道分析仪的要求。 相似文献
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A superresolving three-zone plate is applied to a Fresnel diffractive lens. It is shown that for radial incident polarization this combination produces a focal spot approaching superresolution allowed subdiffractive limit of 0.36lambda/NA for focusing. For media responsive to longitudinal field component only, our phase engineering scheme results in a focal spot size of 0.368lambda/NA. When used with a solid immersion lens, the scheme can generate the smallest focal spot available for passive optics. 相似文献
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报道二维纯位相环带衍射光学透镜的研究。结果表明,在确定位置的像平面的光强分布呈现相当理想的光聚焦作用;同时以1.06μm和0.6328μm两种波长为例,对双波长二维成像的环带衍射透镜进行分析计算,结果表明二种波长的光束都能聚焦于同一像平面。这种元件可方便地用于非可见激光中的对焦与光路调整。 相似文献
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In this article, based on the vector diffraction theory, the effect of specially designed phase modulating optical element by means of an incident tightly focused azimuthally polarized Bessel Gaussian beam in the focal region of high NA lens is investigated numerically. It is observed, that a specially designed diffractive optical modulation element (DOE) can generate multiple focal spot segment of transversely polarized in the focal region by controlling the angles of DOE. Such kind of sub wavelength transversely polarized focal spots segment may find wide applications in multiple optical traps and optical manipulation technology. 相似文献
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紫外衍射微透镜阵列的设计与制备 总被引:1,自引:1,他引:0
为了提高紫外焦平面阵列的填充因子,可以通过微透镜阵列与紫外焦平面阵列的集成,以改善紫外焦平面阵列的探测性能。根据标量衍射理论设计了用于日盲型紫外焦平面阵列的128×128衍射微透镜阵列,其工作中心波长为350nm,单元透镜F数为F/3.56。采用组合多层镀膜与剥离的工艺方法制备了128×128衍射微透镜阵列,对具体的工艺流程和制备误差进行了分析,测量了衍射微透镜阵列的光学性能。实验结果表明:衍射微透镜阵列的衍射效率为88%,与理论值95%有偏差,制备误差主要来自对准误差和线宽误差。紫外衍射微透镜阵列具有均匀的焦斑分布,与紫外焦平面阵列单片集成能较好地改善器件的整体性能。 相似文献