Relationship between height and width of resonance peaks in a whispering gallery mode resonator immersed in water and sucrose solutions

Iwao Teraoka, Haibei Yao, Natalie Huiyi Luo

Research output: Contribution to journalArticle


We employed a recently developed whispering gallery mode (WGM) dip sensor made of silica to obtain spectra for many resonance peaks in water and solutions of sucrose at different concentrations and thus having different refractive indices (RI). The apparent Q factor was estimated by fitting each peak profile in the busy resonance spectrum by a Lorentzian or a sum of Lorentzians. A plot of the Q factor as a function the peak height for all the peaks analyzed indicates a straight line with a negative slope as the upper limit, for each of water and the solutions. A coupling model for a resonator and a pair of fiber tapers to feed and pick up light, developed here, supports the presence of the upper limit. We also found that the round-trip attenuation of WGM was greater than the one estimated from light absorption by water, and the difference increased with the concentration of sucrose.

Original languageEnglish (US)
Pages (from-to)244-251
Number of pages8
JournalOptics Communications
StatePublished - Jun 15 2017



  • Absorption
  • Coupling coefficient
  • Dip sensor
  • Q factor
  • Resonance peaks
  • Whispering gallery mode

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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