Mid-Infrared chemical sensing using a chalcogenide integrated transducer.

Summary Mid-Infrared (2-20 µm) spectroscopic techniques are widely used to identify chemicals substances, allowing quantitative real-time measurements in gases, liquids and solids. The current trend heads to the miniaturization of optical sensors, replacing bulky laboratory instruments (FTIR, monochromators, ATR etc.) by lab-on-chip devices providing portability, mechanical stability, immunity to electromagnetic noise and the potential for batch production. In recent years, optical integrated devices have been fabricated using different technologies such as GaAs, Si, Si3N4 and Ge. Chalcogenide glasses have also emerged as good candidates to manufacture Mid-Infrared photonic integrated circuits thanks to their ability to be deposited as thin films, their broad transparency (up to 20 µm), their potential to be doped with rare earth ions and their refractive index tunability obtained by varying glass composition.