Carbon dioxide mid-infrared sensing based on Dy³⁺-doped chalcogenide waveguide photoluminescence

Climate-active gases, notably carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O), display fundamental absorption bands in the mid-infrared (mid-IR). The detection and monitoring of those gases could be enabled by the development of mid-IR optical sources. Broadband mid-IR on-chip light emission from rare-earth-doped chalcogenide photonic integrated circuits could provide a compact, efficient, and cost-effective gas sensing solution. Mid-IR photoluminescence of dysprosium-doped selenide ridge waveguides obtained under optical pumping at a telecommunication wavelength (∼1.3 µm) is investigated for Dy³⁺ ion concentrations in the 2500-10,000 ppmw range. CO₂ detection at around 4.3 µm is then demonstrated based on absorption of this broadband mid-IR emission.