Miniaturized Mid-Infrared Sensor Technology:
 Potential and Applications

State-of-the-art sensing platforms ideally benefit from miniaturized and integrated optical technologies providing direct access to molecule-specific information. With point-of-care and personalized medicine becoming more prevalent, detection schemes eliminating reagents or labeled constituents facilitate localized on-site analysis close to real-time.”

However, decreasing the analytically probed volume may adversely affect the associated analytical figures of merit such as the signal-to-noise-ratio, the representativeness of the sample, or the fidelity of the obtained analytical signal. Consequently, the guiding paradigm for the miniaturization of optical diagnostic devices should be creating chem/bio sensing platforms that are as small as still useful, rather than as small as possible, and that smartly capitalize on integrated photonics.”

Mid-infrared (MIR; 3-20 μm) sensor technology is increasingly adopted in environmental analysis, process monitoring and biodiagnostics due to the inherent molecular specificity enabling the discrimination of molecular constituents at ppm-ppb concentration levels in condensed and vapor phase media. Recently emerging strategies taking advantage of innovative substrate-integrated waveguide technologies such as mid-infrared transparent fiberoptics, hollow waveguides and planar semiconductor waveguides (e.g., MIR Mach-Zehnder interferometers) in combination with highly efficient light sources such as miniaturized IR spectrometers and broadly tunable quantum cascade lasers facilitate compact yet robust MIR diagnostic platforms for label-free chem/bio sensing and diagnostics that may readily combine with complementary analytical tools.”