Laser tweezing near resonance absorption


Conference Paper

Expressions for radiation-induced forces are presented for the case of a Rayleigh particle at the focus of a Gaussian laser beam. Classical electromagnetic theory was used to obtain the dependence of the scattering and gradient forces on the incident laser frequency, beam convergence angle, and spatial position of the particle in the focus. Numerical analysis performed for particles with a single resonant absorption peak demonstrates the occurrence of enhanced trapping forces at near-resonant frequencies. An indication of the breakdown of the paraxial Gaussian approximation for large convergence angles is also shown by calculation of the scattering force. Use of this technique of gradient force enhancement may provide optical tweezers with enhanced trapping strengths and a degree of specificity.

Full Text

Duke Authors

Cited Authors

  • Agayan, RR; Schmidt, CF; Gittes, F; Kopelman, R

Published Date

  • December 1, 2001

Published In

Volume / Issue

  • 4431 /

Start / End Page

  • 341 - 351

International Standard Serial Number (ISSN)

  • 0277-786X

Digital Object Identifier (DOI)

  • 10.1117/12.447444

Citation Source

  • Scopus