Rapid, sensitive, and reliable detection of aromatic amines, toxic manufacturing byproducts, has been previously achieved with molecular vibrations in the mid-infrared (Mid-IR) region. However, Mid-IR spectroscopic tools are hampered by a need to prepare the samples and the sensor cost. Here, we develop an affordable label-free sensor on a chip, operating in near-infrared (NIR) for ultrasensitive detection of absorption line signatures based on molecular vibrations overtones of the aromatic amine N-methylaniline probe molecule. We design a perforated silicon rib waveguide and fabricate it by milling cylindrical inclusions through the waveguide core. The molecular signatures were monitored when waveguides are embedded in toxic N-methylaniline, experiencing a deflected Talbot effect. We observed that when the Talbot effect is deflected, the absorption lines in NIR are enhanced despite the weakly absorbing nature of the probe molecules. This new spectroscopic strategy can potentially be extended to detect other common toxic byproducts in a chip-scale label-free manner and to enhance the functionality of chemical monitoring.

中文翻译：

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偏转的Talbot介导的近红外泛音光谱作为芯片上的无标签传感器。

以前，通过在中红外（Mid-IR）区域进行分子振动，可以快速，灵敏且可靠地检测芳香胺（有毒的生产副产品）。然而，由于需要准备样品和传感器成本，中红外光谱工具受到了阻碍。在这里，我们开发了一种价格合理的无标记传感器芯片，该传感器以近红外（NIR）操作，可基于芳香胺N-甲基苯胺探针分子的分子振动泛音对吸收线特征进行超灵敏检测。我们设计了一个穿孔的硅肋形波导，并通过在波导芯中铣削圆柱形夹杂物来制造它。当波导嵌入有毒的N中时，对分子标记进行监测-甲基苯胺，经历偏转的Talbot效应。我们观察到，当Talbot效应发生偏转时，尽管探针分子的吸收性质较弱，但NIR中的吸收线仍会增强。这种新的光谱策略可以潜在地扩展为以无芯片级标签的方式检测其他常见的有毒副产物并增强化学监测的功能。