An alignment-free fiber-coupled microsphere resonator for gas sensing applications
Appl. Phys. Lett., vol. 96, no. 231102 (2010).
© 2010 American Institute of Physics. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the American Institute of Physics..
In this paper we report on the assembly of a robust sensor system consisting of a polystyrene microsphere resonator attached to an optical fiber taper. Since the sphere is only supported by the micrometer-sized fiber no further alignment is necessary. This results in a thermally and mechanically well isolated optical resonator system with quality factors as high as 6×105. The narrow resonances of whispering gallery modes supported by the polystyrene resonators shift with temperature at a rate of 3.8 GHz/K. Thus, a sensitive thermometer is established which allows to detect the surrounding gas via its characteristic thermal conductivity.
1 Nano-Optik, Institut für Physik, Humboldt-Universität zu Berlin, 10117 Berlin, Germany
2 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
3 Optical Metrology, Institut für Physik, Humboldt-Universität zu Berlin, 10117 Berlin, Germany
gas sensors, optical resonators, whispering gallery modes.