Perspective on thin film waveguides for on-chip mid-infrared spectroscopy of liquid biochemical analytes.

Miniaturized spectrometers offering low cost, low reagent consumption, high throughput, sensitivity and automation are the future of sensing and have significant applications in environmental monitoring and food safety, biotechnology, pharmaceuticals and healthcare. Mid-infrared (MIR) spectroscopy employing complementary metal oxide semiconductor (CMOS) compatible thin film waveguides and microfluidics shows great promise towards highly integrated and robust detection tools and liquid handling. This perspective provides an overview of emergence of thin film optical waveguides used for evanescent field sensing of liquid chemical and biological samples for MIR absorption spectroscopy. The state of the art of new material and waveguide systems used for spectroscopic measurements in MIR is presented. An outlook on the advantages and future of waveguide-based MIR spectroscopy for application in clinical settings for point-of-care biochemical analysis is discussed.