Surface-enhanced infrared absorption (SEIRA) spectroscopy is a competent method to detect trace quantity of molecules and even protein conformational flexibility by enhancing their vibrational modes. To improve the spectroscopy features, we propose a surface with honeycomb-like (HC) arrangement of aluminum equilateral triangles within a metal-insulator-metal configuration. With adjustable geometric parameters, the HC nanoantennas allow a tunable and wide spectral coverage in the IR. The reflectance measurements correlate extremely well with the numerical simulations. Being compact and insensitive to the light polarization, the HC are appealing for boosting the signal-to-noise ratio and increasing the number of hotspots as required for sensing applications. These nanoantennas are thus suitable for accurate and broadband SEIRA sensing via a spectral overlap between the large plasmonic resonances and the narrow IR vibrational modes of our analyte (vanillin). In line with our previously studied bowties nanoantennas, we demonstrate, using HC, SEIRA enhancement factors greater than 107 achieved at a tuning ratio below 1 stating the best spectral overlap. Around 104 molecules are sensed per HC tip. The investigation results are matching the best-reported SEIRA studies. These findings pave the way toward sensitive, adaptable, and miniaturized IR spectroscopy devices for vital applications like biosensing and environmental monitoring.

中文翻译：

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用于表面增强红外吸收传感的蜂窝状铝天线

表面增强红外吸收 (SEIRA) 光谱是通过增强分子的振动模式来检测痕量分子甚至蛋白质构象灵活性的有效方法。为了改善光谱特征，我们提出了一种在金属-绝缘体-金属配置中具有铝等边三角形蜂窝状 (HC) 排列的表面。HC 纳米天线具有可调节的几何参数，可在 IR 中实现可调谐和宽光谱覆盖。反射率测量与数值模拟非常相关。由于结构紧凑且对光偏振不敏感，HC 在提高信噪比和增加传感应用所需的热点数量方面具有吸引力。因此，这些纳米天线适用于通过大等离子体共振和我们的分析物（香兰素）的窄红外振动模式之间的光谱重叠进行精确和宽带 SEIRA 传感。与我们之前研究的蝴蝶结纳米天线一致，我们证明，使用 HC，SEIRA 增强因子大于 107以低于 1 的调谐比实现，说明最佳光谱重叠。大约 104个每个 HC 尖端检测分子。调查结果与报告最好的 SEIRA 研究相匹配。这些发现为开发用于生物传感和环境监测等重要应用的灵敏、适应性和小型化红外光谱设备铺平了道路。