Towards miniaturized gas sensors based on substrate-integrated hollow waveguides and interband cascade light emitting diodes

In this study, we report the first combination of mid-infrared (MIR) interband cascade light emitting diodes (ICLEDs) with a central emission wavelength at 4.0 mu m and 3.4 mu m, respectively, combined with a substrate-integrated hollow waveguide (iHWG) for the detection of CO2 and CH4 analyzing the antisymmetric stretching of CO2 at 2345 cm-1, and the CH stretching rovibrational mode of CH4 at 3020 cm-1. The obtained calibration functions in the concentration range from 1000 to 10 000 ppmV enabled deriving detection limits in the range of 386-407 ppmV for CO2, and of 302-338 ppmV for CH4. The combination of iHWG and ICLED technology is a pioneering step toward a new generation of miniaturized and low-cost mid-infrared optical sensing devices for rapid gas diagnostics and exceedingly small sample volumes. We report the first combination of MIR ICLEDs combined with a substrate-integrated hollow waveguide for gas detection. This combination is a pioneering step toward a new generation of miniaturized and low-cost MIR optical sensing devices.