High-Q microsphere biosensor - Analysis for adsorption of rodlike bacteria

Hai Cang Ren, Frank Vollmer, Stephen Arnold, Albert Libchaber

Research output: Contribution to journalArticlepeer-review


Theory is Developed for frequency shift and linewidth-broadening induced by rodlike bacteria bound to micro-optical resonators. Optical shift of whispering gallery modes (WGMs) is modeled by introducing a form factor that accounts for random horizontal orientation of cylindrical bacteria bound by their high refractive index cell walls. Linewidth-broadening is estimated from scattering losses. Analytic results are confirmed by measurement using E.Coli as model system (∼102 bacteria/mm2 sensitivity), establishing the WGM biosensor as sensitive technique for detection and analysis of micro-organisms.

Original languageEnglish (US)
Pages (from-to)17410-17423
Number of pages14
JournalOptics Express
Issue number25
StatePublished - Dec 12 2007

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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