论文标题
指纹中红外区域的宽带量子光谱法
Broadband quantum spectroscopy at the fingerprint mid-infrared region
论文作者
论文摘要
许多分子在指纹红外（IR）区域表现出独特的吸收带，从而允许化学鉴定和检测。这使得红外光谱是生物医学诊断，传感和材料表征的必不可少的工具。但是，由于性能相对较差，对低温冷却的需求以及红外光源和光电探测器的高成本，IR范围的测量值是具有挑战性的。在这里，我们证明了使用常规的硅光电探测器从接近IR范围内的测量中揭示样品的MID-IR指纹。我们的方法依赖于以强频率非分类参数下转换产生的相关光子对的量子干扰。我们的技术同时测量了宽指纹区域中的吸收系数和折射率，其精度很高。作为概念验证，我们在7.4-8.4μm波长范围内执行一氧化二氮气体的光谱，并在865-877 nm范围内进行检测。这项工作扩展了量子干涉仪的适用性，包括大气污染物，呼吸诊断，化学安全等的检测。
Numerous molecules exhibit unique absorption bands in the fingerprint infrared (IR) region, allowing chemical identification and detection. This makes IR spectroscopy an essential tool in biomedical diagnostics, sensing, and material characterization. However, measurements in the IR range are challenging due to the relatively poor performance, need for cryogenic cooling, and high cost of IR light sources and photodetectors. Here, we demonstrate that the mid-IR fingerprints of the sample can be revealed from measurements in the near-IR range using conventional silicon photodetectors. Our approach relies on the quantum interference of correlated photon pairs produced in strongly frequency non-degenerate parametric down-conversion. Our technique simultaneously measures the absorption coefficient and refractive index in the broad fingerprint region with high accuracy. As a proof-of-concept, we perform spectroscopy of nitrous oxide gas in the 7.4-8.4 μm wavelength range, with the detection in the 865-877 nm range. This work extends the applicability of quantum interferometry to a range of broad practical appeals, such as detection of atmosphere pollutants, breath diagnostics, chemical safety, and others.
