Miniaturizing gas sensors combining mid-infrared interband cascade light emitting diodes with substrate-integrated hollow waveguides

In this study, we report a compact and versatile gas sensor system combining mid-infrared interband cascade light emitting diodes (MIR-ICLEDs) with substrate-integrated hollow waveguides (iHWGs) toward miniaturized gas sensors. Two readily exchangeable MIR-ICLEDs with center emission wavelengths of 3.4 µm (2941 cm−1) and 5.7 µm (1754 cm−1), respectively, were integrated into a modular sensor system using the iHWG simultaneously as a miniaturized gas cell. The performance of the sensor system for quantitative analysis was evaluated based on calibration functions established for four analytes (i.e., methane, isobutane, acetone, and acetaldehyde) within the respective spectral regions. The utility of such a sensor system as a non-dispersive infrared sensor was tested for various scenarios, including the application of spectral filters, the performance of the individual ICLEDs, and in the analysis of gas mixtures. Furthermore, we demonstrated that the modularity of the sensor design facilitates flexible adaptation to target gas species and available sample volumes, differentiating individual components within gas mixtures.