How latitude location on a micro-world enables real-time nanoparticle sizing

Steve Arnold, D. Keng, E. Treasurer, M. R. Foreman

Research output: Chapter in Book/Report/Conference proceedingChapter


We have devised a method for using the nanoparticle induced frequency shift of whispering gallery modes (WGMs) in a microspheroid for the accurate determination of the nanoparticle size in real time. Before the introduction of this technique, size determination from the mode shift could only be obtained statistically based on the assumption that the largest perturbation occurs for binding at the equator. Determining the latitude of the binding event using two polar WGMs results in an analytic method for size determination using a single binding event. The analysis proceeds by incorporating the binding latitude into the Reactive Sensing Principle (RSP), itself containing a shape dependent form factor found using the Born approximation. By comparing this theory with experiments we find that our theoretical approach is more accurate than point dipole theory even though the optical size (circumference/wavelength) is considerably less than one.

Original languageEnglish (US)
Title of host publicationNATO Science for Peace and Security Series B
Subtitle of host publicationPhysics and Biophysics
PublisherSpringer Verlag
Number of pages11
StatePublished - 2017

Publication series

NameNATO Science for Peace and Security Series B: Physics and Biophysics
ISSN (Print)1874-6500

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • General Physics and Astronomy
  • Electrical and Electronic Engineering


Dive into the research topics of 'How latitude location on a micro-world enables real-time nanoparticle sizing'. Together they form a unique fingerprint.

Cite this