共查询到20条相似文献,搜索用时 46 毫秒
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基于二氧化钒(vanadium dioxide, VO2)的相变原理,提出了一种“树叶型”复合超构材料,能够实现带宽可调谐的半波片功能。VO2薄膜为绝缘态时,复合超构材料可以看作是空芯“树叶型”金属结构,能够实现双频带的半波片功能。在1.01~1.17 THz和1.47~1.95 THz频带范围内能够将y偏振光转换成x偏振光,偏振转换率大于0.9且平均相对带宽为26%。VO2薄膜为金属态时,实芯“树叶型”金属结构的超构材料在1.13~2.80 THz范围内能够实现反射型的宽频带半波片功能,相对带宽为85%。利用瞬时表面电流分布和电场理论详细地分析了带宽可调谐半波片器件的工作原理。本文所提出的“树叶型”复合超构材料半波片器件在太赫兹成像、传感和偏振探测等领域具有潜在的应用前景。 相似文献
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为克服传统光瞳滤波器的缺点,实现系统光学超分辨性能的可调谐性,设计了一种新型可调谐的位相型光瞳滤波器.该光瞳滤波器包括两个λ/4波片和置于其间的λ/2波片,其中λ/2波片分为两个可作相对旋转的区域.研究结果表明,通过旋转λ/2波片的任意一区域不仅可以实现系统横向光学超分辨能力的可调性,而且可以在横向分辨能力提高的同时实现光学系统轴向焦深的扩展以及轴向焦移.
关键词:
光学超分辨
位相型光瞳滤波器
可调谐 相似文献
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Jing-Jun Wu 《中国物理 B》2022,31(5):54216-054216
Once the metalenses are fabricated, the functions of most metalenses are invariable. The tunability and reconfigurability are useful and cost-saving for metalenses in realistic applications. We demonstrate this tunability here via a novel hybrid metalens with the strategic placement of an ultra-thin VO2 layer. The hybrid metalens is capable of dynamically modulating the focusing intensity of transmitted light at a wavelength of 1550 nm, and demonstrate a 42.28% focusing efficiency of the incident light and 70.01% modulation efficiency. The hybrid metalens' optothermal simulations show an optothermal conversion process of dynamic focusing, and a maximum laser density of 1.76×103 W/cm2 can be handled at an ambient temperature lower than 330 K. The hybrid metalens proposed in this work, a light-dose sensitive tunable smart metalens that can protect other instruments/systems or materials from being damaged, has its specific applications such as in anti-satellite blinding, bio-imaging, etc. 相似文献
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多铁性材料可以实现力、电、磁等多物理场之间的相互耦合,在小尺寸、快速响应和低功耗的磁电器件领域具有重要的应用前景.在应用需求的推动下,以具有磁电耦合效应的多铁性材料为基础的磁电器件在设计、微纳加工和性能优化等方面的研究取得了持续的进展.本文简要介绍了基于磁电耦合效应的几种原型器件的最新进展,包括可调谐电感、滤波器、磁电存储器、能量回收器、磁电传感器和磁电天线等,分析总结了各种磁电器件的工作原理及其性能表现,讨论了当前多铁性磁电器件研究所面临的问题和挑战,并提出了改进磁电器件性能的研究方向. 相似文献
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太赫兹技术在最近30年来得到快速发展, 并在医学、生物、农业、材料、安检、通信、天文等领域得到广泛应用. 从太赫兹源的频谱特性可以分为窄带(单频)太赫兹源和宽带太赫兹源. 从频谱技术方面来说, 相干的宽带和窄带太赫兹谱是一种互补性关系, 具有各自的技术特点和应用范围. 宽带太赫兹谱可以用于快速获取较宽频谱范围的分子振转谱, 实现混合特征谱的快速检测或成像. 窄带太赫兹源具有很好的光谱灵敏度和分辨率, 适用于太赫兹抽运-探测、分子振转能级谱精细结构分辨 以及太赫兹远程探测和成像. 因此研制具有可调谐的高峰值功率的窄带太赫兹源是适用于探测和识别分子振转能级指纹谱的应用需求, 而差频技术是获得高功率和宽调谐窄带太赫兹源最重要的技术之一. 为了突出该技术的最新进展, 本综述引证论文仅仅限于近5 年来基于差频技术产生太赫兹波的研究进展, 分为光学激光差频源和量子级联激光器差频源两大部分. 对于光学激光差频源, 分别对目前文献报道的各种双波长差频源和太赫兹产生用的非线性晶体进行分类介绍, 并给出所采用的技术和实验结果; 对于量子级联激光器差频源, 分别介绍了量子级联激光器中的差频产生技术和波长调谐技术的最新进展. 量子级联激光器差频太赫兹源是目前实现量子级联激光器在太赫兹波段室温运转的惟一技术, 是实现小型化、窄带宽调谐和室温运转太赫兹源的新发展领域, 值得关注. 相似文献
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Lin Yikun Qiu Bingshen Gong Di Guo Bingyin 《International Journal of Infrared and Millimeter Waves》1982,3(4):553-566
Tunable properties of optically pumped FIR lasers have been studied on the basis of sixlevel quantum system approach. The signal flow graph method was used to solve the density matrix equations. A set of tuning characteristic curves has been obtained in good agreement with the experimental results for optically pumped HF FIR lasers given by A. de Martino et al. 相似文献
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A.D. Boardman V.V. Grimalsky Y.S. Kivshar S.V. Koshevaya M. Lapine N.M. Litchinitser V.N. Malnev M. Noginov Y.G. Rapoport V.M. Shalaev 《Laser \u0026amp; Photonics Reviews》2011,5(2):287-307
Metamaterial research is an extremely important global activity that promises to change our lives in many different ways. These include making objects invisible and the dramatic impact of metamaterials upon the energy and medical sectors of society. Behind all of the applications, however, lies the business of creating metamaterials that are not going to be crippled by the kind of loss that is naturally heralded by use of resonant responses in their construction. This review sets out some solutions to the management of loss and gain, coupled to controlled and nonlinear behavior, and discusses some critical consequences concerning stability. Under the general heading of active and tunable metamaterials, an international spectrum of authors collaborates here to present a set of solutions that addresses these issues in several directions. As will be appreciated, the range of possible solutions is really fascinating, and it is hoped that these discussions will act as a further stimulus to the field. 相似文献
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Seyedeh Mahsa Kamali Ehsan Arbabi Amir Arbabi Yu Horie Andrei Faraon 《Laser \u0026amp; Photonics Reviews》2016,10(6):1002-1008
Dielectric metasurfaces are two‐dimensional structures composed of nano‐scatterers that manipulate the phase and polarization of optical waves with subwavelength spatial resolution, thus enabling ultra‐thin components for free‐space optics. While high performance devices with various functionalities, including some that are difficult to achieve using conventional optical setups have been shown, most demonstrated components have fixed parameters. Here, we demonstrate highly tunable dielectric metasurface devices based on subwavelength thick silicon nano‐posts encapsulated in a thin transparent elastic polymer. As proof of concept, we demonstrate a metasurface microlens operating at 915 nm, with focal distance tuning from 600 μm to 1400 μm (over 952 diopters change in optical power) through radial strain, while maintaining a diffraction limited focus and a focusing efficiency above 50%. The demonstrated tunable metasurface concept is highly versatile for developing ultra‐slim, multi‐functional and tunable optical devices with widespread applications ranging from consumer electronics to medical devices and optical communications.
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研制了一台高速波长连续扫描光纤激光器。使用SOA作为增益介质,用高速可调谐法珀滤波器作为波长调谐器件,构成的环形腔激光器。测量结果表明,激光器的平均输出功率2.6mW,波长扫描范围40nm,波长扫描范围内功率波动范围小于±0.4dBm,线宽小于0.01nm,扫描速度达到2kHz。 相似文献