title: Ultrasensitive gas-phase chemical sensing based on functionalized photonic crystal nanobeam cavities.
abstract: Photonic crystal nanobeam cavities with high-quality factors are very sensitive to the changes of the dielectric properties of their surroundings. Utilizing this high sensitivity and by applying chemical functionalization, an ultrasensitive chemical sensor for gases based on a nanobeam cavity was demonstrated. A limit of detection of 1.5 parts-per-billion (ppb) in ambient conditions, determined from the noise level of the system, was achieved for nerve agent simulant methyl salicylate. The nanobeam cavity's nonlinear thermo-optical bistability is also utilized to realize a threshold detector for cumulative chemical exposure.
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
authors.forename: William S
authors.initials: WS
authors.lastname: Fegadolli
authors.forename: William M
authors.initials: WM
authors.lastname: Jones
authors.forename: Axel
authors.initials: A
authors.lastname: Scherer
authors.forename: Mo
authors.initials: M
authors.lastname: Li