论文标题
基于石墨烯的插槽天线的成像元面
Imaging Metasurfaces based on Graphene-Loaded Slot Antennas
论文作者
论文摘要
光谱成像仪是彩色相机的一个经典示例，在日常生活中无处不在。但是，大多数此类成像仪都依赖于在每个光谱通道外吸收光的滤芯，对于N通道成像仪产生〜1/N的效率。这在热红外（IR）波长中尤为不可取，其中传感器检测率很低，并且在高度紧凑的系统中，较小的入口瞳孔。衍射光学器件或干涉仪可以实现有效的光谱成像仪，但是对于某些应用，此类系统太大了。我们提出了一个有效且紧凑的热红外光谱成像仪，该光谱仪包括一个由次波长的次曲面组成，该元表面由次波长的间隔，不同调整的插槽天线与光敏元素耦合。在这里，我们使用石墨烯演示了这个想法，该想法具有光响应，直至热IR波长。联合天线共振在超过1/N效率极限的石墨烯中产生宽带吸收。我们为天线的光学特性建立了电路模型，并证明了与全波模拟的一致性。从理论上讲，我们还证明了六频通道元横向面的宽带〜36％的自由空间到含料耦合效率。这项研究为紧凑的CMOS综合热IR光谱成像仪铺平了道路。
Spectral imagers, the classic example being the color camera, are ubiquitous in everyday life. However, most such imagers rely on filter arrays that absorb light outside each spectral channel, yielding ~1/N efficiency for an N-channel imager. This is especially undesirable in thermal infrared (IR) wavelengths, where sensor detectivities are low, as well as in highly compact systems with small entrance pupils. Diffractive optics or interferometers can enable efficient spectral imagers, but such systems are too bulky for certain applications. We propose an efficient and compact thermal infrared spectral imager comprising a metasurface composed of sub-wavelength-spaced, differently-tuned slot antennas coupled to photosensitive elements. Here, we demonstrate this idea using graphene, which features a photoresponse up to thermal IR wavelengths. The combined antenna resonances yield broadband absorption in the graphene exceeding the 1/N efficiency limit. We establish a circuit model for the antennas' optical properties and demonstrate consistency with full-wave simulations. We also theoretically demonstrate broadband ~36% free space-to-graphene coupling efficiency for a six-spectral-channel metasurface. This research paves the way towards compact CMOS-integrable thermal IR spectral imagers.
