Functionalized Lateral Surface Coated Lasers for Chem-Bio Detection

We present a class of compact, monolithic, photonic sensors consisting of multiple section edge emitting lasers with functionalized lateral surface coatings for low level detection of chemical or biological agents. Specifically, we discuss 8 mum times 250 mum Pd-coated H₂ sensors and configurations to reduce the minimum detection limit from 138 ppm for passive sensors to 1 ppm for active sensors. Compared with conventional optical H₂ sensors that use fiber gratings, surface plasmon resonances, or surface reflectance, our sensors offer the advantages of smaller size, wider dynamic range, monolithic integration of laser source and detector, and 2-D scalability to arrays of sensors that are functionalized to detect different agents.