Nanofiber near-field light-matter interactions for enhanced detection of molecular level displacements and dynamics

Ilsun Yoon, Sarah E. Baker, Kanguk Kim, Nicholas O. Fischer, Daniel Heineck, Yinmin Wang, Sadik C. Esener, Donald J. Sirbuly

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


We experimentally demonstrate that plasmonic nanoparticles embedded in the evanescent field of subwavelength optical waveguides (WGs) are highly sensitive to distances normal to the propagation of light, showing an ∼10× increase in spatial resolution compared to the optical field decay of the WG. The scattering cross-section of the Au nanoparticle is increased by the plasmon-dielectric coupling interaction when the nanoparticle is placed near the dielectric surface of the WG, and the decay of the scattering signal is enhanced, showing angstrom level distance sensitivity within 10 nm from the WG. Numerical studies with the finite-difference time-domain (FDTD) method correlate well with the experimental results. To demonstrate real-time monitoring of a single molecule stretching in the evanescent field, we linked individual single-stranded DNA molecules between the WG and plasmonic nanoparticles and pushed on the nanoparticles with fluidic forces. The simple design and ease of obtaining optical feedback on molecular displacements makes our approach ideal for new in situ force sensing devices, imaging technologies, and high-throughput molecular analysis.

Original languageEnglish (US)
Pages (from-to)1440-1445
Number of pages6
JournalNano Letters
Issue number4
StatePublished - Apr 10 2013
Externally publishedYes


  • Nanophotonics
  • light-matter interaction
  • molecular ruler
  • plasmonic nanoparticle
  • sensor
  • subwavelength nanowire

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering


Dive into the research topics of 'Nanofiber near-field light-matter interactions for enhanced detection of molecular level displacements and dynamics'. Together they form a unique fingerprint.

Cite this