Bespoke optical springs and passive force clamps from shaped dielectric particles

S. H. Simpson, D. B. Phillips, D. M. Carberry, S. Hanna*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

23 Citations (Scopus)

Abstract

By moulding optical fields, holographic optical tweezers are able to generate structured force fields with magnitudes and length scales of great utility for experiments in soft matter and biological physics. It has recently been noted that optically induced force fields are determined not only by the incident optical field, but by the shape and composition of the particles involved [Gluckstad J. Optical manipulation: sculpting the object. Nat Photonics 2011;5:7-8]. Indeed, there are desirable but simple attributes of a force field, such as orientational control, that cannot be introduced by sculpting optical fields alone. With this insight in mind, we show, theoretically, how relationships between force and displacement can be controlled by optimizing particle shapes. We exhibit a constant force optical spring, made from a tapered microrod and discuss methods by which it could be fabricated. In addition, we investigate the optical analogue of streamlining, and show how objects can be shaped so as to reduce the effects of radiation pressure, and hence switch from non-trapping to trapping regimes. (C) 2012 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)91-98
Number of pages8
JournalJournal of Quantitative Spectroscopy and Radiative Transfer
Volume126
DOIs
Publication statusPublished - Sep 2013

Keywords

  • Optical trapping
  • Dielectric cylinder
  • Optical spring
  • Force clamping
  • Anisotropic particle
  • Discrete dipole approximation
  • LAGUERRE-GAUSSIAN BEAMS
  • NANOWIRES
  • MICROMACHINES
  • MANIPULATION
  • TWEEZERS
  • OBJECT
  • TRAPS
  • LIFT

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