相位阶跃变化型太赫兹波带片

对相位阶跃变化型太赫兹波带片衍射效率进行了理论研究。根据标量衍射理论,相位阶跃变化型波带片可以完成对高斯光束太赫兹波的聚焦。相位阶跃变化型波带片的衍射规律与薄透镜聚焦的规律相似。对其在光轴以及焦平面上太赫兹强度分布及衍射效率进行了模拟,通过与相位连续变化型,台阶型波带片的衍射效率进行对比分析,结果表明相位阶跃变化型波带片具有更好的衍射效率和性能。计算了一种相位阶跃变化型太赫兹波带片的加工尺寸,适合微机械加工法,有很好的应用价值。     

软X线波带片的制作

菲湟尔波带片是一种对衍射率大致为1的软X射线具有透射作用的新型光学元件。本文介绍用电子束曝光制作X线波带片的新方法。通过与反应离子刻蚀配合,能够制成高宽比大、分辨率高的波带片。用试作的波带片聚焦波长为9nm的同步加速器幅射光时,在焦点距离为100mm的位置上,能够将辐射光聚焦成直径为2μm的斑点。     

阵列菲涅耳波带片波前探测性能研究

在高功率激光系统中,激光束小尺度畸变波前探测是实现激光束中频段波前补偿与控制的重要前提。采用阵列菲涅耳波带片作为激光束波前传感的子孔径分割器,研究其聚焦性能,讨论了波带片的结构如阵列数目和阵列尺寸对波前探测精度的影响。仿真结果表明,选取合适的波带片结构参数可以使小尺度畸变波前的重构误差小于十分之一个波长。为了检测阵列菲涅耳波带片作为波前传感器检测波前畸变的性能,实现小尺度波前畸变检测的目的,构建了激光波前畸变检测光路系统。实验结果表明了阵列菲涅耳波带片检测波前畸变的可行性和准确性.     

用衍射场叠加法分析四种误差下的X光波带片

利用叠加所有圆环的解析近似衍射场的方法来计算和分析随机环带位置误差、宽度误差、扩散和粗糙度对X射线波带片的效率和分辨率的影响。用Strehl比来量化和衡量与理想波带片有偏差的波带片的性能，对两个波带片例子分别用Strehl极限确定了其能容许的四种误差极限。以一个Ni软X射线波带片为例，用叠加圆环衍射场的方法分析了随机环带位置误差和宽度误差对主焦点效率和分辨率的影响；以一个SiO2／Ni硬X射线溅射切片波带片为例，计算了两种材料的相互扩散和粗糙度对衍射效率和分辨率的影响。计算结果表明，四种误差越大，主焦点效率越小，分辨率越差，对第一个波带片例子而言，随机环带位置误差均方根和宽度误差均方根小于最外环宽度的30％；而对于第二个波带片例子，扩散区宽度和粗糙度均方根分别小于最外环宽度的105％和50％时，得到的Strehl比在Strehl极限之上。     

电控位相型液晶菲涅耳波带片的特性

利用电场中液晶分子的可控双折射效应对制成电场可调的位相型衍射式菲涅耳波带片。对菲涅耳波带片的原理做了理论分析,测试了其最大衍射效率,给出不同电压Ｆ的不同衍射图像,并对衍射图像的周期性变化做了理论分析。     

一种可用于光学准直的新型波带片

一种可用于光学准直的新型波带片在现代光学技术中，波带片已应用于准直、分束、互连和编码等多种领域。普通波带片的衍射斑中心是一较大的亮点，用于激光准直时，其准直精度不高。Ｊ．Ｏｊｅｄａ－Ｃａｓｔａｎｅｄａ等人［１］提出一种焦点处光强为零的振幅型波带片，利...     

利用铁电畴结构直接写入电控菲涅尔波带片

菲涅尔波带片是光学中的一个基本元件.在本文中,通过带电金属电极在53 μm厚的铌酸锂品体表面的扫描,我们利用铁电畴结构制备出了最大半径为913 μm的菲涅尔波带片.在偏置电压的作用下,我们对菲涅尔波带片的聚焦能力进行了研究.主焦点处的光强随着外加电压的变化而变化,我们得到的最大衍射效率在2.0%左右.     

产生空心高斯光束的改进型菲涅耳波带片

空心高斯光束是一种不携带轨道角动量的空心光束，它的暗斑尺寸较小，函数公式简单，在原子引导、粒子操控、光通信等领域具有潜在应用价值。近年来，关于波带片的研究不断深入，通过使用等效光瞳函数理论，说明了波带片的焦平面复振幅分布函数正比于其等效光瞳函数的傅里叶-贝塞尔变换，可以通过此关系设计产生空心高斯光束的波带片。作为一个应用，分别计算了用来产生一阶、三阶、六阶空心高斯光束的波带片的等效光瞳函数，据此设计了这三个波带片的结构参数，并研究了改变波长和焦距对波带片结构参数和暗斑尺寸的影响。基于瑞利-索末菲衍射积分对这三个改进型菲涅耳波带片的焦平面光场进行仿真模拟，仿真结果与预期相符，验证了使用等效光瞳函数法设计波带片的可靠性和精确性。     

热压印光刻技术复制波带片图形研究

针对只需单次曝光的菲涅尔波带片器件,给出了结合电子束光刻和热压印光刻进行大规模复制的完整工艺路线,即首先采用电子束光刻制作热压印模版,之后用热压印光刻进行波带片的大规模复制,所制得的波带片图形的最外环宽度为250 nm,直径为196μm,环数为196环.初步实验结果表明,这种方法具有很好的重复性和易用性,且可以进行低成本波带片的精确复制.     

LIGA技术制作Fresnel波带片的研究

简要介绍了利用ＬＩＧＡ技术中同步辐射光刻、微电铸技术制作α粒子编码成像波带片的研究,讨论了编码波带片的结构和影响波带片的平面和层析分辨率的参数。根据实验要求设计和研制了一种α粒子编码成像波带片。     

波带板法检测凹非球面的研究

非球面在光学系统中占有重要的地位,但其应用一直受到光学加工和检测技术的限制。波带板（Zone plate）法是对非球面进行检测的重要方法之一。文章详细介绍了波带板检测法的原理以及波带板的计算、制作过程,并针对在实际应用中,由于入射光和反射光两次通过波带板后有多级衍射光,导致不容易判别在什么位置才能方便观察,以及哪一组干涉图样才能正确反映反射镜信息这个问题,对整个检测过程进行了衍射模拟计算,为实验检测提供了参考。最后,通过实验检测,并与其它检测方法得到的结果进行比较,证明了所得结果的正确。     

贝塞尔高斯光束经菲涅尔波带片产生特殊聚焦光强分布

基于衍射光学方法,研究了不同阶数的贝塞尔高斯光束经过环形菲涅尔波带片后,在波带片的焦点附近所形成光强分布。入射光束为高阶贝塞尔高斯光束,聚焦区域获得了空心光强分布,入射光束的阶数越高,空心尺寸越大;菲涅尔波带片的数目越多,空心长度越短。入射光束为零阶贝塞尔高斯光束,在聚焦区域获得了针形光束和局域空心光束。这些具有特殊光强分布的光束在激光加工以及粒子囚禁等领域有着潜在应用价值。     

Offset Fresnel zone plate antennas

The theory of offset Fresnel zone plate antennas is presented. Explicit formulae for the design of the zone boundaries for the offset Fresnel zone plate are given. Theorectical equations and numerical results for the far-field analysis are presented. It is found that when the offset angle increases, the zone boundaries become more elliptic and the plate becomes more asymmetric in the E-plane. With the number of full wave zones and the plate width in the W-plane fixed, the plate width in the E-plane increases with the offset angle, which keeps the projected aperture area constant. Within a limited range of offset angles, the offset configuration can be employed without degrading the radiation performance much. For large offset angles, however, the asymmetry of the configuration may lead to increased sidelobes and decreased antenna directivity. An experiment with one particular phase reversal zone plate antenna with 30° offset angle shows good agreement between the measured antenna pattern and the theoretical prediction.     

DESIGN OF mm-WAVE PHASE-CORRECTING FRESNEL ZONE PLATE REFLECTOR ANTENNA WITH CONTINUOUS STRUCTURE

Based on scalar diffraction optics theory, a new type of mm-wave antenna(diffraction antenna) phase-correcting Fresnel zone plate with continuous structure is described in this paper. It has the advantages of thinner thickness, lighter weight and design flexibility. The design theory and space shadow are discussed in details, and the measured results are presented. The results show that the properties of this kind of antenna is closed to paraboloid reflector.     

Multilayer phase correcting fresnel zone plate reflector antennas

Owing to its flat nature and light weight etc., the Fresnel zone plate antenna is becoming very attractive for such applications as DBS reception and receive-only VSAT. The disadvantages of low efficiency and high sidelobes of the simple and the phase reversing zone plates can be improved by using phase correcting techniques. In this paper, a systematic investigation on the efficiency and sidelobe performance of subzone phase correcting zone plate antennas is presented. The design of a form of multilayer phase correcting zone plate reflector is described. A quarter-wave zone plate reflector constructed with three dielectric layers and metallized rings is reported, with measured peak efficiency of 55 per cent.     

螺旋型波带片成像的空间分辨率研究

研究了1阶螺旋型波带片(SZP)的聚焦特性,提出了一种数值计算SZP空间分辨率的方法。通过数值计算获得SZP的聚焦特性曲线,计算出SZP对刀边图形的响应曲线,根据响应曲线并结合光学相干叠加原理,确定SZP的空间分辨率。理论分析得到模拟计算和实验结果的验证。     

菲涅尔波带片的设计与制作

一种有效的实验用波带片的制作方法，详细说明了波带片的设计与制作过程以及各步骤的注意事项，并由实验给出了测试结果。     

Focusing characteristics of curvilinear half-open Fresnel zone plate lenses: plane wave illumination

A diffraction field-focusing equation based on a specific conical-segment linearization procedure is derived for the Fresnel zone plate (FZP) lens of arbitrary curved profile and is applied for contrasting plane, spherical, parabolic and conical zone plate lenses, convex-side illuminated by a paraxial plane wave front. Two sets of 100-GHz curvilinear and plane FZP lenses are studied numerically with regards to their dimensions, axial focusing intensity and footprint, and frequency bandwidth. For the first set , where the curvilinear and plane lenses share a common lens base aperture and have equal focal lengths, the following new finding has resulted: regardless of their different in shape profiles the FZP lenses have equal zone numbers and produce similar axial focusing. The second set also consists of plane, spherical, parabolic and conical lenses. They share a common apex, and have equal in diameter base apertures and focal lengths but different thicknesses. For such disposition and proportions, the FZP lenses possess different zone numbers and focusing parameters (gain, efficiency, footprint and bandwidth). The belief that the curvilinear FZP have superior (or inferior) electromagnetic characteristics, compared to those of the plane FZP lens with equal number of zones is not in general true. Their relative focusing qualities can vary significantly depending on the lens positioning and dimensions.     

Design of objective lens with reflective spherical Fresnel zone plate

An objective lens composed of a spherical Fresnel zone plate mirror and aspheric mirrors is designed.The Fresnel zone plate with a spherical shape is analyzed, and the method to approximately replace the aspherical mirror with spherical Fresnel zone plate is deduced. The objective lens is designed with a single spherical Fresnel zone plate mirror and three aspherical mirrors. Under the condition of 100 × magnification,2.5 Fresnel number and 120° field angle, the modulation transfer function can reach above 40% at 0.6 line pairs/mm on the magnification side, and the distortion is less than 2.2%. This method can provide a reference for the application of Fresnel zone plate in visible light imaging, and has a bright future with the continuous development of the fabrication technique of Fresnel devices.