All-dielectric metasurface absorbers for uncooled terahertz imaging
All-dielectric metasurface absorbers for uncooled terahertz imaging
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DOI：
10.1364/optica.4.000601
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发表时间：
2017-06-20
期刊：
影响因子：
10.4
通讯作者：
Padilla, Willie J.
中科院分区：
文献类型：
--
作者：
Fan, Kebin;Suen, Jonathan Y.;Padilla, Willie J.
由于缺乏高功率源和有效的探测器，在电磁频谱的太赫兹（THz）范围内成像是困难的。几十年来，由于太赫兹成像的大量潜在应用，人们一直在努力设计焦平面阵列。在这里，我们提出并证明了一种替代方法，利用全电介质超颖表面吸收器，作为辐射的通用转换器。入射的太赫兹波被超颖表面吸收，转化为热量，随后被红外摄像机检测到。我们实现了由亚波长圆柱形谐振器组成的超颖表面，该超颖表面在THz频率下实现衍射限制成像而无需冷却。低的导热率和扩散率显著限制了相邻像素之间的热传导，从而提高了空间分辨率和成像时间。与传统的基于金属的超材料类似，我们的全介电超表面吸收体可以扩展到电磁波谱的其他波段，为实现新型非制冷测辐射热成像提供了蓝图。(C)2017美国光学学会
Imaging in the terahertz (THz) range of the electromagnetic spectrum is difficult owing to the lack of high-power sources and efficient detectors. For decades, there has been tremendous effort to fashion focal plane arrays for THz imaging owing to the great number of potential applications. Here, we propose and demonstrate an alternative approach which utilizes all-dielectric metasurface absorbers that act as universal converters of radiation. Incident THz waves are absorbed by the metasurface, converted to heat, and subsequently detected by an infrared camera. We realize a metasurface consisting of sub-wavelength cylindrical resonators that achieve diffraction-limited imaging at THz frequencies without cooling. The low thermal conductivity and diffusivity significantly limit the thermal conduction between neighboring pixels, thus improving the spatial resolution and imaging time. Similar to conventional metallic-based metamaterials, our all-dielectric metasurface absorber can be scaled to other bands of the electromagnetic spectrum, offering a blueprint to achieve novel uncooled bolometric imaging. (C) 2017 Optical Society of America