THz sensing offers unique advantages including strong penetrability, low photon energy, and specific recognition of biomolecules and chemicals. However, current label-free THz sensors all operate below 1 THz, severely limiting applications as many drugs and chemicals vibrate at higher THz frequencies. Moreover, the THz detection of analytes at picogram levels is challenging. Here, a modern graphene-enhanced THz metasurface label-free sensor is presented. Its tunable resonance from ∼1.8 to 2.6 THz matches the fingerprint resonant frequencies of various analytes not currently detectable by label-free THz sensing. Quantitative detection of trace 1,3-DNB (absorbing at ∼2.52 THz) is first achieved with a maximum reflectance sensitivity of ∼10% pmol^–1 and a detection limit of 42 pg. The sensor can also be refreshed, minimizing cost and being more environmentally friendly. Our strategy expands application scenarios of label-free THz sensing, enhancing its potential in fields such as the pharmaceutical industry, environmental monitoring, and security.

中文翻译：

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石墨烯增强的可刷新超表面扩展了太赫兹无标记传感的分析物，并实现了皮克级检测限


太赫兹传感具有独特的优势，包括穿透性强、光子能量低以及对生物分子和化学物质的特异性识别。然而，目前的无标记太赫兹传感器都在 1 THz 以下工作，这严重限制了应用，因为许多药物和化学品在更高的太赫兹频率下振动。此外，皮克级分析物的太赫兹检测具有挑战性。在这里，提出了一种现代石墨烯增强的 THz 超表面无标记传感器。其 ∼1.8 至 2.6 THz 的可调谐振频率与目前无标记太赫兹传感无法检测到的各种分析物的指纹谐振频率相匹配。首先以 ∼10% pmol^–1 的最大反射灵敏度和 42 pg 的检测限实现痕量 1,3-DNB（在 ∼2.52 THz 处吸收）的定量检测。传感器还可以更新，从而最大限度地降低成本并更加环保。我们的策略拓展了无标记太赫兹传感的应用场景，增强了其在制药、环境监测和安全等领域的潜力。