Filterless non-dispersive infra-red gas detection: A proof of concept

For the first time, we demonstrate the detection of carbon dioxide (CO
₂
) using a non-dispersive infra-red (NDIR) technique that does not require an expensive CMOS-incompatible optical filter. This is achieved by employing a differential IR thermopile detector with micro-engineered (plasmonic) optical properties, fabricated in a commercially available standard CMOS MEMS process. The proof of concept demonstrated here represents a milestone in low-cost gas sensing spectroscopy, and has the potential to impact profoundly in the entire IR field; many consumer electronics applications (wearables, smartphones, tablets and portable medical devices) will become viable, leading to high volume commercial applications for plasmonic devices.