Broadband gradient index microwave quasi-optical elements based on non-resonant metamaterials
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Utilizing non-resonant metamaterial elements, it is demonstrated that complex gradient index optics can be constructed exhibiting low material losses and large frequency bandwidth.Abstract:
Utilizing non-resonant metamaterial elements, we demonstrate that complex gradient index optics can be constructed exhibiting low material losses and large frequency bandwidth. Although the range of structures is limited to those having only electric response, with an electric permittivity always equal to or greater than unity, there are still numerous metamaterial design possibilities enabled by leveraging the non-resonant elements. For example, a gradient, impedance matching layer can be added that drastically reduces the return loss of the optical elements due to reflection. In microwave experiments, we demonstrate the broadband design concepts with a gradient index lens and a beam-steering element, both of which are confirmed to operate over the entire X-band (roughly 8-12 GHz) frequency spectrum.read more
Citations
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Gradient-index meta-surfaces as a bridge linking propagating waves and surface waves
TL;DR: It is demonstrated theoretically and experimentally that a specific gradient-index meta-surface can convert a PW to a SW with nearly 100% efficiency, and may pave the way for many applications, including high-efficiency surface plasmon couplers, anti-reflection surfaces, light absorbers, and so on.
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High-efficiency broadband anomalous reflection by gradient meta-surfaces.
Shulin Sun,Kuang-Yu Yang,Chih Ming Wang,Ta Ko Juan,Wei Ting Chen,Chun Yen Liao,Qiong He,Shiyi Xiao,Wen Ting Kung,Guang-Yu Guo,Guang-Yu Guo,Lei Zhou,Din Ping Tsai,Din Ping Tsai +13 more
TL;DR: This work combines theory and experiment to demonstrate that a carefully designed gradient meta-surface supports high-efficiency anomalous reflections for near-infrared light following the generalized Snell's law, and the reflected wave becomes a bounded surface wave as the incident angle exceeds a critical value.
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Three-dimensional broadband and high-directivity lens antenna made of metamaterials
TL;DR: In this article, a three-dimensional broadband, low-loss, dual-polarization, and high-directivity lens antenna using gradient index (GRIN) metamaterials, which is composed of multi-layer microstrip square-ring arrays.
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Metamaterial-based gradient index lens with strong focusing in the THz frequency range
TL;DR: In this paper, the optical properties of spectrally broadband metamaterial-based gradient index (GRIN) lenses have been studied for terahertz imaging systems with high spatial resolution.
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Metamaterial-based gradient index lens with strong focusing in the THz frequency range
TL;DR: The design, fabrication and the measurement of the optical properties of spectrally broadband metamaterial-based gradient index (GRIN) lenses that allow one to focus terahertz radiation to a spot diameter of approximately one wavelength open the path to a new class of adaptive THz optics by extension of the concept to tunable meetamaterials.
References
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