Alcohol Vapor Sensor Based on Fluorescent Dye-Doped Optical Waveguides

This paper presents an alcohol vapor sensor realized using stretchable optical waveguides doped with commercially available fluorescent dyes. The fabrication technology is based on a cost-efficient replication method, employing polydimethylsiloxane materials mixed with the dye Nile red. Upon introduction of ethanol vapors, the fluorescent emission was found to have a wavelength shift of ~20 nm with a response time of ~10 s. Observing the fluorescence intensity of the shifted emission spectrum in a periodically varying environment inside a gas-sensing setup showed a respective variation with introduction of ethanol vapor. The intensity variation also showed the reversibility of the sensor. The sensing platform is found to hold much promise for further integration and multiplexing.