Laser Spectroscopy

Laser Physics

, Volume 21, Issue 1, pp 130-136

First online:

Brownian diffusion of gold nanoparticles in an optical trap studied by fluorescence correlation spectroscopy

  • J. WangAffiliated withThe Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Lifescience and Technology, Xi’an Jiaotong University
  • , Z. LiAffiliated withThe Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Lifescience and Technology, Xi’an Jiaotong University
  • , C. P. YaoAffiliated withThe Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Lifescience and Technology, Xi’an Jiaotong University
  • , F. XueAffiliated withThe Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Lifescience and Technology, Xi’an Jiaotong University
  • , Z. X. ZhangAffiliated withThe Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Lifescience and Technology, Xi’an Jiaotong University Email author 
  • , G. HüttmannAffiliated withInstitut für Biomedizinische Optik, Universität zu Lübeck

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Abstract

The effect of thermal-induced Brownian motion on gold nanoparticles (Au NPs) in optical traps is studied by fluorescence correlation spectroscopy (FCS) method. The Brownian motion and optical trapping potential are investigated by the decay time of the FCS curve and the laser power. It is shown that that the probability of finding a gold nanoparticle in the trap depends on the ratio of the optical energy of the particle to its thermal energy. A power threshold is observed by the decay time as a function of laser power. The experimental studies show that the temperature rise does not seriously affect the average number of particles in the focal spot, but the average residence time is more sensitively affected by the temperature.