Enhancing the sensitivity of a whispering-gallery mode microsphere sensor by a high-refractive-index surface layer

Research output: Contribution to journalArticlepeer-review

Abstract

We examine properties of whispering gallery modes (WGMs) in a dielectric microsphere coated with a high-refractive-index layer. With an increase in layer thickness, the photonic field of a WGM moves near the sphere's surface, while the peak in its radial distribution narrows, followed by backtracking and broadening. During these changes, the resonance frequency decreases. The radial compression exposes a stronger evanescent field to the surroundings, yet the mode retains a sharp resonance peak in the frequency domain. The high-refractive-index layer will enhance the sensitivity of WGM frequency-shift sensors when used to detect adsorption of molecules and a change in refractive index in the surroundings. A possibility to match resonance shifts of different radial modes in the measurement of refractive indices is proposed.

Original languageEnglish (US)
Pages (from-to)1434-1441
Number of pages8
JournalJournal of the Optical Society of America B: Optical Physics
Volume23
Issue number7
DOIs
StatePublished - Jul 2006

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Atomic and Molecular Physics, and Optics

Fingerprint Dive into the research topics of 'Enhancing the sensitivity of a whispering-gallery mode microsphere sensor by a high-refractive-index surface layer'. Together they form a unique fingerprint.

Cite this