Optical fiber-top microcavity sensor for CO2 detection

In the paper, we present a miniature fiber-optic CO2 sensor by in-situ printing of a special polymer Fabry-Pérot (FP) microcavity on the end facet of standard single-mode optical fiber. A photo-crosslinkable poly(ionic liquid)s (PILs) with high CO2 adsorption capability has been developed to fabricate the polymer optical microcavity via an optical 3D µ-printing technology. Experimental results show that such an optical CO2 microsensor has very high sensitivity and fast response and thus is very promising for environment and exhaust gas monitoring applications.