Optical trapping of nanoshells near resonance

Brooke C. Hester, Rani B. Kishore, Kristian Helmerson, Naomi J. Halas, Carly Levin

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review


We examine the enhancement of optical trapping forces due to plasmon resonances of nanoshells. Nanoshells are nanoscale particles with a dielectric core and metallic coating that exhibit tunable plasmon resonances. Theory predicts that the optical trapping force may be three to fifty times larger for trapping-laser wavelengths near resonance than for wavelengths far from resonance [1]. The resonance absorption of nanoshells can be tuned by adjusting the ratio of the radius of the dielectric core, r1, to the total radius, r2 [2]. Using back focal plane detection, we measure the trap stiffness of optical tweezers, from lasers at 973 nm and 1064 nm, for single trapped nanoshells with several different r1/r2 ratios. Enhanced trapping strengths are not found through these measurements done with single wavelength optical traps. A tunable-wavelength laser trap will enable more conclusive results.

Original languageEnglish
Title of host publicationPlasmonics
Subtitle of host publicationMetallic Nanostructures and Their Optical Properties VI
Publication statusPublished - 21 Nov 2008
Externally publishedYes
EventPlasmonics: Metallic Nanostructures and Their Optical Properties VI - San Diego, United States of America
Duration: 10 Aug 200814 Aug 2008

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferencePlasmonics: Metallic Nanostructures and Their Optical Properties VI
CountryUnited States of America
CitySan Diego


  • Nanoshell
  • Optical trap
  • Optical tweezers
  • Plasmon resonance

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