In this study, an innovative approach based on fiberoptically coupled substrate-integrated hollow waveguide (iHWG) gas cells for the analysis of low sample volumes suitable for remote broad- and narrow-band mid-infrared (MIR; 2.5–20 μm) sensing applications is reported. The feasibility of remotely addressing iHWG gas cells, configured in a double-pass geometry via a reflector, by direct coupling to a 7-around-1 mid-infrared fiber bundle is demonstrated, facilitating low-level hydrocarbon gas analysis. For comparison studies, two iHWGs with substrate dimensions of 50 × 50 × 12 mm (L × W × H) and geometric channel lengths of 138 and 58.5 mm, serving as miniature light-guiding gas cells, were fiber-coupled to a Fourier transform infrared spectrometer enabling broadband MIR sensing. In addition to the fundamental feasibility of this concept, the achievable sensitivity toward several gaseous hydrocarbons and the reproducibility of assembling the fiber-iHWG interface were investigated.

中文翻译：

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光纤耦合基片集成空心波导：中红外远程气体传感器的创新方法

在这项研究中，一种基于光纤耦合衬底集成空心波导（iHWG）气室的创新方法可用于分析少量样品，适用于远程宽带和窄带中红外（MIR; 2.5–20μm）传感应用被报道。演示了通过直接耦合到7围1左右的中红外光纤束，通过反射器对以双通几何结构配置的iHWG气室进行远程寻址的可行性，这有助于进行低级烃类气体分析。为了进行比较研究，将两个衬底尺寸为50×50×12 mm（L×W×H）且几何通道长度分别为138和58.5 mm的iHWG光纤耦合至傅里叶变换红外光谱仪实现宽带MIR感应。除了这个概念的基本可行性之外，