Chemical microanalysis with cavity-enhanced optical waveguide devices
Authors: Loock H-P, Barnes J. A., Bescherer K., Brzezinski A., Gagliardi G., Gribble A., Janz S., Ma R., Munzke D., Ongo G., Saunders J., Waechter H., Xu D.-X.
Autors Affiliation: Department of Chemistry, Queen’s University, Kingston, ON, K7L 3N6, Canada;
Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica (INO), Via Campi Flegrei, 34 I-80078 Napoli, Italy;
Institute for Microstructural Sciences, National Research Council, Ottawa, ON, K1A 0R6, Canada
Abstract: Three examples of cavity-enhanced measurements of refractive index and optical absorption are discussed. Using microphotonic silicon-on-insulator ring-resonators we determine the concentration of cyclohexane and m-xylene at detection levels of 300-3000 ppm. The gases are first absorbed into a siloxane polymer and its refractive index change is detected by a characteristic wavelength shift of the cavity resonance. In a second device phase-shift cavity ring-down spectroscopy is applied to simultaneously measure the optical absorption at two wavelengths of either a dye, nucleic acids or a pharmaceutical component. Multiplexing the ring-down measurement permits dual wavelength absorption spectroscopy without the use of a dispersion element. Finally, a combination of resonance wavelength measurements and cavity ring-down spectroscopy is used to simultaneously determine the change in refractive index and the absorption induced by adsorption of ethylene diamine on a 300 µm silica sphere. A whispering gallery mode of the microsphere resonator is excited with intensity modulated light and the intensity and AM modulation phase of the Rayleigh backscattered light is measured.
KeyWords: Cavity enhanced spectroscopy; Cavity ring-down; Microphotonics; Microsphere resonators; Silicon-on-insulators; Waveguide cavity; Adsorption; Ethylene; Light absorption; Microspheres; Nucleic acids; Resonators; Silica; Spectroscopy; Spheres; Wavelength; Refractive indexDOI: 10.1117/12.920231Citations: 1data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2020-08-02References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here