Optical sorting of gold nanoparticles based on the red-shift of plasmon resonance

Martin Ploschner, Tomáš Čižmar, Michael Mazilu, Andrea Di Falco, Kishan Dholakia

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


We present an experimental technique allowing size-based all-optical sorting of gold nanoparticles. The technique is based on the red-shift of plasmon resonance, due to retardation effects, with increasing particle size. As a result, smaller gold nanoparticles are influenced strongly by shorter wavelengths whereas larger gold nanoparticles are influenced more strongly by longer wavelengths. We utilise this retardation effect and realize sorting in a system of two counter-propagating evanescent waves, each at different wavelengths that selectively guide nanoparticles of different sizes in opposite directions. We validate this concept by demonstrating bidirectional sorting of gold nanoparticles of either 150 or 130 nm in diameter from those of 100 nm in diameter within a mixture.

Original languageEnglish
Title of host publicationOptical Trapping and Optical Micromanipulation IX
Publication statusPublished - 2012
EventOptical Trapping and Optical Micromanipulation IX - San Diego, CA, United States
Duration: 2012 Aug 122012 Aug 16

Publication series

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


ConferenceOptical Trapping and Optical Micromanipulation IX
Country/TerritoryUnited States
CitySan Diego, CA

All Science Journal Classification (ASJC) codes

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


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