aNanooptik, Institut für Physik, Humboldt-Universität zu Berlin, Hausvogteiplatz, D-10117 Berlin, Germany
bLaboratory of Physical Chemistry, Swiss Federal Institute of Technology (ETH), CH-8093 Zürich, Switzerland
Abstract:
In this paper, we demonstrate a novel method for optimizing the in- and out-coupling of light confined in the fundamental high-Q whispering-gallery mode of a microsphere resonator via an external prism coupler. The technique relies on the use of a near-field probe to map the modes of the resonator and to obtain topographical information at the same time. We demonstrate the feasibility and efficiency of this technique by applying it to a sphere with a radius of 59 μm.