A Dual-Spectroscopy Platform Combining Lanthanide Photoluminescence and Mid-Infrared Spectroscopy for Gas Sensing

Mid-infrared (MIR) absorption and photoluminescence (PL) spectroscopy have independently demonstrated outstanding performance for gas sensing. Here, the potential of each technique is illustrated through two representative examples. MIR spectroscopy is exemplified by the laser-based air quality analyzer (LAQA), which combines miniaturized substrate-integrated hollow waveguides (iHWGs) and quantum cascade lasers (QCLs) for the selective detection of CO₂, CO, and SO₂ under real underground mining conditions. In parallel, PL spectroscopy is represented by a terbium-based lanthanide complex (TbHPMIDA), a solid-state sensing material for detecting volatile organic compounds such as acetone and limonene. Building on these advances, a miniaturized iHWG-based platform integrating MIR and PL spectroscopy is presented. Using acetone as a model analyte, simultaneous and sequential measurements demonstrate that both spectroscopic techniques operate without mutual interference, highlighting the potential of this orthogonal approach for future portable environmental and biomedical gas sensing.