Trace Sensing with Miniaturized Mid-Infrared Sensors

Optical chemical sensor technology in the mid-infrared (MIR) spectral range (3-20 mum) is gaining importance in process monitoring, environmental analysis, security/surveillance applications, and the biomedical field due to the increasing demand for robust sensor technology with inherent molecular specificity. Interfacing IR-transducers with continuous measurement situations in the gas and liquid phase becomes increasingly feasible with the advent of appropriate waveguide technology (e.g., MIR transparent optical fibers and planar waveguides), protective surface coatings (e.g., diamond-like carbon, sol-gels, polymers, etc.), and the availability of advanced light sources such as room-temperature operated quantum cascade lasers (QCLs) leading to miniaturized IR diagnostics.