Study of Optical Force and Torque of Optical Tweezers on Gold Nanoparticles

Project: National Science and Technology CouncilNational Science and Technology Council Academic Grants

Project Details

Abstract

This proposal aims to study the optical manipulation of optical tweezers on single or multiple gold nanoparticles (GNPs), gold nanorods (GNRs) or gold nanowires (GNWs) for trapping, aligning and grouping. The optical force and torque induced by a focused linearly polarized CW laser beam on these GNPs/GNRs are investigated theoretically and experimentally. An experimental setup, including linearly polarized laser beam, dark-field condenser and high-N.A. objective (100x), will be built to study the trapping and alignment of a single GNP/GNR, and then the grouping of multiple GNPs (grouping: chains or arrays). In addition, we plan to use the multiple multipole (MMP) method to investigate numerically the optical binding forces between multiple GNPs/GNRs and the gradient force of Gaussian beam for trapping. The stable equilibrium can be identified for the grouping and patterning. For the alignment, the role of wavelength-dependent optical torque playing on GNR/GNW will be identified, and the accompanying plasmonic heating will be analyzed. These optical manipulations are strongly related to the surface plasmon resonance (SPR) of metallic NPs. Using this light-matter interaction, a 2D-array pattern could be self-assemblied and photothermal-imprinted on substrate for the applications of meta surface of changing optical chirality and biosensing, e.g. surface enhanced Raman scattering (SERS).

Project IDs

Project ID:PB10408-5734
External Project ID:MOST104-2221-E182-053
StatusFinished
Effective start/end date01/08/1531/07/16

Keywords

  • gold nanoparticle
  • gold nanorod
  • gold nanowire
  • optical tweezers
  • Gaussian beam
  • optical force
  • optical torque
  • surface plasmon resonance
  • self-assembly
  • alignment
  • trapping
  • photothermal imprinting
  • meta surface

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