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介绍了一种基于计算全息的非对称多台阶衍射光学元件印模制备方法,研究了相位型计算全息的工作原理和设计方法,建立了相应的光学系统和衍射光波模型,设计了求取相位型印模微结构的算法流程。在理论分析的基础上,以叠心图案为例,利用MATLAB分别仿真了2台阶、4台阶、8台阶、16台阶衍射光学元件的相位信息以及表面微结构形貌,并对比了其再现图像的质量,发现台阶数越多,再现图像的质量越好。获得印模空间高度数据以及表面结构分布后,利用单点金刚石车削技术,采用快刀加工方式,分别加工了元件尺寸为6 mm×6 mm,最小特征尺寸为30 um的2台阶和4台阶印模,并获得了实际加工的台阶轮廓曲线以及表面结构轮廓。最后采用紫外固化纳米压印技术实现了4台阶印模的复制过程,并对复制样品进行了图像再现,结果表明该方法能用于非对称低台阶数衍射光学元件印模的制备。 相似文献
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垂直扫描白光干涉法(VSWLI)是一种非接触式三维表面轮廓测量方法。蝙蝠翼作为VSWLI当中一种固有的缺陷,尤其在被测样品的台阶高度小于光源的相干长度时,台阶边缘处的蝙蝠翼尤为显著。相移干涉法不存在这种缺陷,但是存在相位模糊的问题。提出一种将Carré等步长相移算法与快速傅里叶变换(FFT)相干峰值检测技术相结合的白光干涉解调算法。该算法基于逐次变分模态分解(SVMD)与Hausdorff距离(HD)联合去噪。分别以高度为500 nm和1 200 nm的连续台阶器件和高度为10μm的标准台阶作为测试样品,进行实验测量验证。所提出的算法能够有效地抑制台阶高度跳变处的蝙蝠翼,克服相位模糊问题。 相似文献
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建立了数值与物理方法结合的参考透镜法,对离轴数字全息显微系统进行畸变相位校正.对离轴全息图进行频谱分析,通过频谱滤波、移位的数值方法对一次相位畸变进行校正.在参考光路中引入参考透镜,根据频谱中心能量判别参考透镜的轴向最佳位置,利用物理方法对多次相位畸变进行校正.在相位校正理论分析的基础上,结合实验用参考透镜法验证其有效性和准确性.微台阶表面形貌测量结果表明,参考透镜法能够准确校正相位畸变,通过校正的相位可以获取44nm标准微台阶形貌数据,测量标准差能够达到0.8nm,且测量结果与轮廓仪测量结果一致.表明参考透镜法能够有效、准确地校正离轴数字全息显微系统的畸变相位. 相似文献
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为了分析屏蔽电缆在电磁脉冲作用下的时域响应,对基于最小相位法的频域等效方法进行了研究。首先,通过建立转移阻抗测试系统的电路模型,推导系统的频域传递函数,并验证其为最小相位系统与全通系统的级联;其次,采用最小相位法,对测得的幅频曲线进行相位重构,根据推导的传递函数的零、极点分布,对重构的最小相位传递函数进行相位补偿;最后,将补偿后的传递函数与瞬态干扰信号在频域相乘后变换到时域,得到了屏蔽电缆的时域响应。仿真及实验结果验证了该方法的有效性。 相似文献
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大数值孔径衍射透镜的优化设计方法 总被引:4,自引:0,他引:4
本文针对大数值孔径衍射透镜工艺制作难的问题,以菲涅耳衍射透镜为例,研究了相位匹配原理并提出了一种优化设计二元大数值孔径衍射透镜的方法。在菲涅耳衍射透镜原理的基础上,确定了优化设计多相位台阶衍射透镜的结构参数,并给出了一个设计实例,最后对结果元件的衍射效率进行了分析与讨论。 相似文献
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为获得较大的光束电控偏转范围,使用空间分辨力高达8 m的反射式液晶空间光调制器实现了对入射632 nm激光的电控偏转。利用双光束共焦干涉方法测量了液晶空间光调制器的电控相位延迟特性,最大相移量可达3。根据二元光学理论和器件的电控相位延迟特性,设计了周期台阶相位模式和相应的加载灰度图,以最大衍射效率实现对入射光束的闪耀电控偏转。结果表明:相位模式台阶数为8时,可以实现10 mrad的光束偏转,闪耀级次衍射效率可达46%。利用二元光学的衍射模型对影响衍射效率的关键因素进行了分析,认为器件较低的填充因子和周期台阶模式相位重置点诱导的指向矢回程区是限制光束衍射效率的主要因素。 相似文献
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A new method for eliminating the chromatic aberration of a diffractive optical element (DOE) for wideband wavelengths is presented. The wideband-wavelength diffractive optical element (WBDOE) consists of two aligned DOE's. The use of different dispersive materials for the two DOE's eliminates chromatic aberration. The design and simulation of a WBDOE for the visible spectrum are presented. 相似文献
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The diffractive optical element (DOE) is widely used to generate various illumination modes in the projection lithography system. The working principle and design methods of the DOE are discussed in detail in this paper. A mixed multi-region design method is proposed to calculate the phase of DOE based on the poor spatial coherence of excimer laser, using the Gerchberg–Saxton (GS) algorithm. The DOEs generating circular, dipole and quadrupole illumination modes are designed and simulated by three different methods: single region design, repeated multi-region design and mixed multi-region design. The performance of these DOEs are compared and analyzed with these three design methods. The mixed multi-region design method is used to design the DOEs generating three illumination modes, the diffraction efficiencies are greater than 85%, and the non-uniformities of illumination are less than 3%. The analysis results indicate that the DOE designed by the mixed multi-region design can achieve higher diffraction efficiency and illumination uniformity of the far-field intensity distribution without modifying the GS algorithm. 相似文献
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Through researching and validating, a set of optical designs using a diffractive optical element (DOE) and optimization process has been derived in this paper. We put forward a set of theories to solve the numerous quality issues in imaging and applied it to an optical design. For an optical design to be successful, it must comply with the standards of the optical system. Optical designers must also take into consideration imaging quality, wherein the most influential aspects are chromatic aberration and monochromatic aberration. We complied with systemic standards such as effective focal length and total system length. Diffractive Optical Element, based on the theory of wave phase difference, takes advantage of negative Abbe number, which might significantly eliminate chromatic aberrations of optics. Following the advanced technology applied to micro lens and etching process, precisely made micro DOE element now is possible to be manufactured in a large number. A 350× zoom lens with DOE is demonstrated in the proposal. The results show that regardless of whether chromatic aberration is axial or longitudinal, issues concerning the optical lens's chromatic aberration could be significantly reduced. 相似文献
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A method that permits aberration correction and wave-front reshaping with a diffractive optical element (DOE) is described. Two aligned DOE's made of two different dispersive materials are used. The different dispersions of the two materials in addition to freedom in choosing their thicknesses enables the chromatic aberration and the wave fronts to be manipulated. Design and simulation of such DOE's are described. 相似文献
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Kant reported [J. Mod. Optics 47, 905 (2000)] a formulation for solving the inverse problem of vector diffraction, which accurately models high-NA focusing. Here, Kant's formulation is adapted to the method of generalized projections to obtain an algorithm for designing diffractive optical elements (DOEs) that reshape the axial point-spread function (PSF). The algorithm is applied to design a binary phase-only DOE that superresolves the axial PSF with controlled increase in axial sidelobes. An 11-zone DOE is identified that axially narrows the PSF central lobe by 29% while maintaining the sidelobe intensity at or below 52% of the peak intensity. This DOE could improve the resolution achievable in several applications without significantly complicating the optical system. 相似文献
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衍射光学元件较球面、非球面光学元件在校正色差方面具备较大优势,尤其是在红外光学领域,应用衍射光学元件可进一步增加光学系统的设计自由度。随着红外光学市场的进一步增大,常规的衍射光学金刚石车削技术难以满足大规模需求,精密模压技术成为解决上述问题的关键技术。模具设计是实现精密模压的重点,为了缩减模具设计周期,该文采用有限元仿真方法对模具进行预先设计及补偿,并试加工。采用单站式精密模压机对设计的模具进行了精密模压试验。模压试验结果表明:采用合理的工艺参数,能够实现衍射光学元件面形精度PV达到0.56 μm,位置误差<0.011 mm,环带高度误差<0.12 μm,验证了仿真预先补偿在衍射光学模具设计中的有效性。 相似文献