Protein detection by optical shift of a resonant microcavity

F. Vollmer, D. Braun, A. Libchaber, M. Khoshsima, I. Teraoka, S. Arnold

Research output: Contribution to journalArticlepeer-review


We present an optical biosensor with unprecedented sensitivity for detection of unlabeled molecules. Our device uses optical resonances in a dielectric microparticle (whispering gallery modes) as the physical transducing mechanism. The resonances are excited by evanescent coupling to an eroded optical fiber and detected as dips in the light intensity transmitted through the fiber at different wavelengths. Binding of proteins on the microparticle surface is measured from a shift in resonance wavelength. We demonstrate the sensitivity of our device by measuring adsorption of bovine serum albumin and we show its use as a biosensor by detecting streptavidin binding to biotin.

Original languageEnglish (US)
Pages (from-to)4057-4059
Number of pages3
JournalApplied Physics Letters
Issue number21
StatePublished - May 27 2002

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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