Optical trapping of nanoshells

Brooke C. Hester, Alice Crawford, Rani B. Kishore, Kristian Helmerson, Naomi J. Halas, Carly S. Filgueira

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


We investigate near-resonant trapping of Rayleigh particles in optical tweezers. Although optical forces due to a nearresonant laser beam have been extensively studied for atoms, the situation for larger particles is that the laser wavelength is far from any absorption resonance. Theory predicts, however, that the trapping force exerted on a Rayleigh particle is enhanced, and may be three to fifty times larger for frequencies near resonance than for frequencies far off resonance.1 The ability to selectively trap only particles with a given absorption peak may have many practical applications. In order to investigate near-resonant trapping we are using nanoshells, particles with a dielectric core and metallic coating that can exhibit plasmon resonances. The resonances of the nanoshells can be tuned by adjusting the ratio of the radius of the dielectric core, r1, to the overall radius, r2, which includes the thickness of the metallic coating.2,3 Our nanoshells, fabricated at Rice University, consist of a silica core with a gold coating. Using back focal plane detection, we measure the trap stiffness of a single focus optical trap (optical tweezers), from a diode laser at 853 nm for nanoshells with several different r1/r2 ratios.

Original languageEnglish (US)
Title of host publicationOptical Trapping and Optical Micromanipulation IV
StatePublished - Dec 1 2007
EventOptical Trapping and Optical Micromanipulation IV - San Diego, CA, United States
Duration: Aug 26 2007Aug 29 2007


OtherOptical Trapping and Optical Micromanipulation IV
Country/TerritoryUnited States
CitySan Diego, CA


  • Nanoshell
  • Optical trapping
  • Optical tweezers
  • Plasmon
  • Resonant trapping

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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