Chen Ziwei, Li Dongxiao, Zhou Hong, Liu Tao, Mu Xiaojing
Key Laboratory of Optoelectronic Technology & Systems of Ministry of Education, International R & D center of Micro-nano Systems and New Materials Technology, Chongqing University, Chongqing 400044, China.
Nanoscale. 2023 Sep 1;15(34):14100-14108. doi: 10.1039/d3nr02830e.
Surface-enhanced infrared absorption (SEIRA) has proven its ability to improve the detection performance of traditional infrared spectroscopy at unprecedented levels. However, the resonant frequency of the metamaterial absorber (MA) lacks tunability once the structure is fabricated, which poses a challenge for broadband fingerprint retrieval of molecules. Here, we propose a pixelated and electric tunable hybrid graphene MA with a broadband response for molecular fingerprint retrieval. Loss engineering is employed to optimize the sensing sensitivity of MA. The resonant frequency of MA is approximately linearly modulated with a change in the graphene Fermi level. This design allows a meta-pixel to match multiple characteristic absorption spectra, thereby establishing a one-to-many mapping relationship between spatial and spectral information. The one-to-many mapping relationship greatly reduces the number of meta-pixels. As a concept demonstration, we integrate 9 meta-pixels to achieve full spectral coverage from 1000 cm to 2000 cm. Based on the broadband spectral properties of the sensor, we demonstrate its potential for multi-fingerprint detection, quantitative detection, chemical identification, and compositional analysis. Our proposed hybrid graphene MA can be easily integrated with other on-chip devices, providing a potential platform for optical sensing, infrared spectroscopy, and photodetection.
表面增强红外吸收（SEIRA）已证明其能够以前所未有的水平提高传统红外光谱的检测性能。然而，一旦超材料吸收体（MA）的结构制造完成，其共振频率就缺乏可调性，这对分子的宽带指纹检索构成了挑战。在此，我们提出一种具有宽带响应的像素化且电可调谐的混合石墨烯MA，用于分子指纹检索。采用损耗工程来优化MA的传感灵敏度。MA的共振频率随石墨烯费米能级的变化近似呈线性调制。这种设计允许一个元像素匹配多个特征吸收光谱，从而在空间和光谱信息之间建立一对多的映射关系。这种一对多的映射关系极大地减少了元像素的数量。作为概念验证，我们集成了9个元像素以实现从1000 cm至2000 cm的全光谱覆盖。基于该传感器的宽带光谱特性，我们展示了其在多指纹检测、定量检测、化学识别和成分分析方面的潜力。我们提出的混合石墨烯MA能够轻松地与其他片上器件集成，为光学传感、红外光谱和光电探测提供了一个潜在平台。
