Enhanced sensitivity in single-mode silicon nitride stadium resonators at visible wavelengths

• DOI: 10.1364/ol.41.005377
• Publication Date: 2016-11-11T21:11:03Z
• Authors: Mario Chemnitz; Gabriele Schmidl; Anka Schwuchow; Matthias Zeisberger; Uwe Hübner; Karina Weber; Markus A. Schmidt
• Keywords: Extinction ratio; Coupled mode theory

The marker-free and noninvasive detection of small traces analytes in aqueous solution using integrated optical resonators is an emerging technique within bioanalytics. Here, we present a single-mode silicon-nitride stadium resonator operating at the red edge visible spectrum, showing sensitivities larger than 200 nm/RIU transmission dips with extinction ratios more 15 dB. We introduce mathematical model that allows analyzing sensitivity properties guided mode only. Large geometric parameter scans finite element simulations show optimal sensing conditions are achieved for TM-polarized modes close to modal cutoff. Due its compactness short operation wavelength, anticipate applications our