共查询到20条相似文献,搜索用时 15 毫秒
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Ruizhe Zhao Xiaofei Xiao Guangzhou Geng Xin Li Junjie Li Xiaowei Li Yongtian Wang Lingling Huang 《Advanced functional materials》2021,31(27):2100406
The diverse design freedom and mechanisms of metasurfaces motivate the manipulation of polarization in an ultrashort distance with subwavelength resolution and make metasurfaces outperform conventional polarization optical elements. However, in order to enhance the information capability and encryption security of metasurface holograms, polarization manipulation together with multiplexing technologies are still highly desired. Here, a birefringent dielectric metasurface with the capability of encoding a grayscale image in real-space based on Malus's law by utilizing the inhomogeneous polarization distribution and realizing the reconstruction of a vectorial holographic image in k-space with the help of the phase profiles of different polarization components of output light is demonstrated. This novel functionality is realized by exploiting the manipulation of polarization and phase of output light simultaneously offered by the dielectric metasurface. The proposed method may enhance the information capability and security level of applications such as the anticounterfeiting and encryption. 相似文献
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利用计算机全息实现数字图像的全息变换 总被引:5,自引:0,他引:5
利用信息光学原理以及数字图像全息变换的概念,成功实现了黑白点阵图像的全息变换及其逆变换;利用变换过程中的一组参数作为密钥,获得了加密数字图像的一种新方法。 相似文献
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Plasmonic Metasurfaces for Simultaneous Thermal Infrared Invisibility and Holographic Illusion 下载免费PDF全文
Xin Xie Xiong Li Mingbo Pu Xiaoliang Ma Kaipeng Liu Yinghui Guo Xiangang Luo 《Advanced functional materials》2018,28(14)
In 1860s, Gustav Kirchhoff proposed his famous law of thermal radiation, setting a fundamental contradiction between the infrared reflection and thermal radiation. Here, for the first time an ultrathin plasmonic metasurface is proposed to simultaneously produce ultralow specular reflection and infrared emission across a broad spectrum and wide incident angle range by combining the low emission nature of metal and the photonic spin–orbit interaction in spatially inhomogeneous structures. As a proof‐of‐concept, a phase gradient metasurface composed of sub‐wavelength metal gratings is designed and experimentally characterized in the infrared atmosphere window of 8–14 µm, demonstrating an ultralow specular reflectivity and infrared emissivity below 0.1. Furthermore, it is demonstrated that infrared illusion could be generated by the metasurface, enabling not only invisibility for thermal and laser detection, but also multifunctionalities for potential applications. This technology is also scalable across a wide range of electromagnetic spectrum and provides a feasible alternative for surface coating. 相似文献
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Enlightened by holography metasurfaces for controlling the propagation of light, speckle image holography nanostructures were introduced into both fluorescent and phosphorescent OLEDs in order to achieve high efficiency and engineered emission profile. The resulting current efficiency and external quantum efficiency of the nanostructured fluorescent green emission OLEDs were enhanced by up to 99% and 104%, respectively. This enhancement feature is comparable to that of phosphorescent red- and blue-emission OLEDs. Furthermore, the enhancement ratios were retained approximately as a constant when the viewing angle varied from −60° to 60° for all three color devices. Experimental and theoretical results directly prove that the light steering is independent of the emission materials, the wavelength, radiation angle, and the polarization of the emitted light. We anticipate this paradigm may offer new opportunities for high-end optoelectronic designs and applications. 相似文献
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All‐Dielectric Metasurfaces for Simultaneous Giant Circular Asymmetric Transmission and Wavefront Shaping Based on Asymmetric Photonic Spin–Orbit Interactions 下载免费PDF全文
Fei Zhang Mingbo Pu Xiong Li Ping Gao Xiaoliang Ma Jun Luo Honglin Yu Xiangang Luo 《Advanced functional materials》2017,27(47)
The control of polarization and wavefront plays an important role in many optical systems. In this work, a monolayer metasurface is proposed to simultaneously realize circular asymmetric transmission (AT) and wavefront shaping based on asymmetric spin–orbit interactions. Circularly polarized incidence, accompanied with arbitrary wavefront modulation, experiences spin‐selected destructive or constructive interference. An extinction ratio of ≈10:1 and an AT parameter of ≈0.69 at 9.6 µm, as well as a full width half‐maximum of ≈2.9 µm (≈30% of the peak wavelength), are measured with the designed metasurface. These measured results are more than four times of those achieved with previous monolayer chiral structures. As far as it is known, this is the first report on the realization of simultaneous giant AT and arbitrary wavefront modulation with only one metasurface. Due to its fabrication simplicity and the multifunctionality of the designed metasurface, this work may provide a promising route to replace bulky cascading optical components with only one ultrathin metasurface for chiroptical spectroscopy, chiral imaging, optical communication, and so forth. 相似文献
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数字全息再现像的细节显示和视觉畸变矫正 总被引:5,自引:1,他引:5
在分析数字全息系统的最小分辨距离和再现像平面上的采样间隔的基础上,提出了一种在用菲涅耳变换法再现数字全息图时,能清楚显示再现像细节的简单方法,这种方法能有效地提高再现场的显示分辨率。通过给由CCD记录的数字全息图补零,可使再现像平面上采样间隔减小,使再现像具有更多的像素,得到保留了更多记录信息的高质量再现像。用同样的方法,也可以矫正由于CCD靶面尺寸在水平和竖直方向上的不一致造成再现像的视觉畸变。实验结果表明此方法有很好的效果。 相似文献
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Metasurfaces: All‐Dielectric Metasurfaces for Simultaneous Giant Circular Asymmetric Transmission and Wavefront Shaping Based on Asymmetric Photonic Spin–Orbit Interactions (Adv. Funct. Mater. 47/2017) 下载免费PDF全文
Fei Zhang Mingbo Pu Xiong Li Ping Gao Xiaoliang Ma Jun Luo Honglin Yu Xiangang Luo 《Advanced functional materials》2017,27(47)
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针对含有混合噪声的声呐图像,提出了中值滤波与形态学滤波的组合算法,并对常用的图像滤波算法以及算法组合进行了定量分析比较,仿真结果表明,中值滤波和形态学滤波的组合算法对于声呐图像中混合噪声的滤除是较为理想的. 相似文献
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Ad hoc routing protocols that use broadcast for route discovery may be inefficient if the path between any source–destination pair is frequently broken. We propose and evaluate a simple mechanism that allows fast route repair in on demand ad hoc routing protocols. We apply our proposal to the Ad hoc On-demand Distance Vector (AODV) routing protocol. The proposed system is based on the Controlled Flooding (CF) framework, where alternative routes are established around the main original path between source–destination pairs. With alternative routing, data packets are forwarded through a secondary path without requiring the source to re-flood the whole network, as may be the case in AODV. We are interested in one-level alternative routing. We show that our proposal reduces the connection disruption probability as well as the frequency of broadcasts. 相似文献
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分析负反馈电路时,在采用拆环分析(方框图)法的基础上,叠加反馈受控源,可使分析计算直观、简单、易于掌握。若在此基础上再叠加直通受控源,则既可克服计算中由于忽略直通效应引起的误差,同时仍保留分析计算直观简单的特点,其分析计算结果与解析法得出的一致。 相似文献
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纹理图像的特征提取和分类 总被引:7,自引:4,他引:3
文章提出了一种纹理图像特征提取的有效算法.该算法利用纹理信息的频域分布以及尺度特性,并在此基础上进行纹理分类.这里采用了分类性能良好的支撑矢量机作为分类器,实验结果表明该方法提取的特征向量稳定,在类别数目比较大时也能得到较高的分类精度. 相似文献
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介绍了一种新型多路数控增益放大器。该放大器具有8路模拟信号输入通道,采用3位数字信号控制通道位;每个通道均具有256级增益控制,采用8位数字信号控制放大倍数;输入信号采用绝对值处理电路,具备极性判别信号输出。采用多芯片微组装技术实现,体积小、重量轻,可用做小型微机处理电路的模拟接口芯片。简要介绍了基于该放大器的某设备控制与保护系统的应用示例。 相似文献
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在电路的等效变换中,当电路中含受控电源时,电路的化简往往是一个难点,通常的做法是保留控制量支路。本文介绍一种不用保留控制量支路的处理方法,可在处理某些类似问题时显得更简便、灵活。文中给出了算例以及用谊方法求解电路的过程。 相似文献
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在给定参,物光波的偏振态和位相差的关系以后,用光致各向异性介质记录的偏振全息图的光学常数分布便被确定。这样,可以把偏振全息图看作是一种复杂的偏振元件,按照偏振元件的矩阵理论,可以求出偏振全息图的透射短阵,透射矩阵与照明光的琼斯矢量相乘,使可以求出再现光波的琼斯矢量。 相似文献