Experimental realization of a switchable filter based on a dynamically transformable array

We introduce a geometrically reconfigurable metasurface whose artificial "atoms" will reorient within unit cells in response to a thermal stimulus in the microwave spectrum. It can alternate between two contrasting behaviors under different temperatures and serve as a switchable filter that allows the incident energy to be selectively transmitted or reflected with an excess of 10 dB isolation at certain frequencies for both polarizations. The experimental results are consistent with the theoretical simulations, verifying the availability of an innovative method for manipulating electromagnetic waves with the merits of higher controllability for dynamic behavior and greater flexibility in the design process.     

大口径反射镜高反射膜研究进展

大口径反射镜是大型反射式光学系统中关键的光学元件,在工作波段的反射率直接决定了光学系统的性能。随着地基、天基观测设备的发展,对大口径反射镜高反射膜提出了更宽的工作波段、更高的反射率、更好的环境适应性等要求。针对这些挑战,各种新的膜系结构、新的镀制方法、新的膜层材料纷纷出现,满足了大口径反射镜高反射膜的各种需求。本文对近些年国内外的大口径反射镜高反射膜研究进展予以综述,并预测大口径反射镜高反膜制备的技术趋势将由铝反射膜向银反射膜、由热蒸发向磁控溅射发展。     

离子源辅助电子枪蒸发制备Ge1-xCx薄膜

应用电子枪蒸发纯Ge,考夫曼离子源辅助的方法在Ge基底上沉积了Ge1－xCx薄膜.制备过程中,Ge作为蒸发材料,CH4作为反应气体.通过改变CH4/(CH4+Ar)的气体流量比（G）,制备了G从40％到85％的Ge1－xCx薄膜.应用X射线衍射仪（XRD）测量了Ge1－xCx薄膜的晶体结构,使用傅里叶红外光谱仪（FTIR）测量了2～22 μm的光学透过率,X射线光电子能谱测试（XPS）计算得到C的含量随G的变化关系,用纳米压痕硬度测试计测量了Ge1－xCx薄膜的硬度,原子力显微镜（AFM）测量了G为60％,85％时Ge1－xCx薄膜的表面粗糙度.测试结果表明：制备的Ge1－xCx薄膜在不同的G值下均为无定形结构.折射率随着G值的增加而减小,在3.14～3.89之间可变,并具有良好的均匀性以及极高的硬度.     

Method to accurate calibrate deposition rates of EUV multilayer coatings

Random thickness error is an important factor which effects the calibration accuracies of deposition rates for extreme ultraviolet （EUV） multilayer coatings fabricated by sputter deposition techniques. A least square fitting method is proposed to determine deposition rates and extract random thickness errors accurately. The validity of this method is shown by evaluating two deposition systems with control abilities of -0.1 nm and better than 0.01 nm respectively.     

Frequency selective surface with a flat topped passband

Two frequency selective surface (FSS) configurations with flat topped passband are presented in this paper. One configuration is single layer FSS with,λ/4 thickness dielectric loaded on both sides,and the other is double layers FSS.Based on the modal matching method,the frequency response properties including angle effect and polarization effect of both FSS configurations are analyzed,and the plots of the frequency versus transmission coefficient are obtained for different incident angles and polarizations.It is shown that the structure with the single layer FSS embedded centrally in the ,k/2 thickness dielectric has a wider flat top bandwidth of 6.8 GHz than that of the double layers FSS of 3 GHz.In addition,the fabrication of single layer is relatively easier than the double layers FSS.     

Analysis,fabrication,and measurement of Y aperture element frequency selective surface

The analysis of Y aperture element frequency selective surface (FSS) using the spectral domain method and the moment method is presented.With the vacuum depositing and photolithography,the corresponding Y aperture element FSS was produced,and it was tested in the microwave darkroom.The calculated and measured results are in good agreement.     

Ku/Ka波段双通带频率选择表面设计研究

为了实现双通带频率选择表面(FSS)在较厚介质基底、 较大频带间隔和入射角度下的工程应用, 设计制备了一种性能优良的Ku/Ka波段双频FSS结构. 利用FSS栅瓣图分析了FSS具有稳定滤波特性的条件. 应用矢量模式匹配法计算了基于分形技术和复合图形技术的FSS的传输特性. 根据单元谐振模式和FSS传输特性归纳了厚介质基底、较远双通带FSS的设计原则, 最终优化出一种由方环复合“Y”环单元组成的FSS结构. 结果表明: 该结构在6.7 mm厚介质基底上0°-45°扫描范围内, 在Ku/Ka波段具有稳定的双频传输特性, 透过率均优于75%. 这为设计基底厚度较大、频带间隔较远、入射角度要求较高的双带FSS结构提供了理论参考与实验依据. 关键词： 频率选择表面 双通带 分形结构FSS 复合结构FSS     

等离子辅助镀膜技术

传统的电子束蒸发工艺提供了高速率的沉积，但由于成膜分子的能量较低，使沉积的薄膜排列密度很低，其性能和块材料区别很大，已有不少学者发现了很多金属和氧化物薄膜具有典型的柱状结构，薄膜的低排列密度造成了其光学常数和机械性能不如块状材料，近几年发展起来的高功率等离子体辅助镀膜技术解决了上述问题，本文报道了我国自己研制的等离子体源（GIS）的性能指标，用这个源所做的单层TiO2膜的成膜工艺与质量，以及用等离子辅助沉积的减反射膜的工艺。     

结合傅里叶变换合成法设计均匀薄膜

基于傅里叶变换合成法的基本原理,合成了一个K9基底上的负滤光片,合成的渐变折射率薄膜具有期望光学特性,但实际制备难度很大,因此将其细分为足够多层离散折射率的均匀薄膜,由于实际薄膜材料种类有限,不能获得任意折射率膜层,鉴于两层高低折射率薄层可近似为一层中间折射率膜层的思想,将膜系转化成一个可实际制备的膜系结构:膜系采用ZrO2和SiO2两种膜料,膜层总数为183层,经单纯形调法优化后,膜层总厚度为7.09 μm,通带和截止带内平均透射比分别为97.56%和3.13%,其结果优于直接采用傅里叶方法合成的非均匀膜系,与期望透射比曲线吻合更好.说明通过这种思想设计任意光谱特性的膜系是可行的,也使傅里叶变换合成法设计的薄膜实际制备成为可能.     

非球面碳化硅反射镜的加工与检测

为了获得高精度非球面碳化硅(SiC)反射镜,对非球面碳化硅反射镜基底以及改性后碳化硅反射镜表面的加工与检测技术进行了研究。介绍了非球面计算机控制光学表面成型（CCOS）技术及FSGJ-2非球面数控加工设备。采用轮廓检测法和零位补偿干涉检测法分别对碳化硅反射镜研磨和抛光阶段的面形精度进行了检测,并采用零位补偿干涉检测法及表面粗糙度测量仪对最终加工完毕的碳化硅反射镜的面形精度和表面粗糙度进行检测。测量结果表明：各项技术指标均满足设计要求,其中非球面碳化硅(SiC)反射镜实际使用口径内的面形精度（RMS值）为0.016λ(λ=0.6328μm）,表面粗糙度（RMS值）为0.85nm。