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Dielectric materials in Optical Traps

  1. Dec 11, 2011 #1
    Why are optical traps constructed using beads that are made of dielectric materials? What property of dielectrics is being employed here? Would a non-dielectric material still experience radiation force from photons?

  2. jcsd
  3. Dec 13, 2011 #2

    Andy Resnick

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    They don't have to be dielectric- metals can also be trapped.

    What is generally done, for a 'vanilla' single-beam trap, is to trap homogeneous dielectric particles with an index of refraction higher than the solvent- the beam is then modeled as a potential well, and the particle 'falls' into the well.

    One can use birefringent particles and the trap will exert a torque:


    One can trap conducting particles or particles with a *lower* relative refractive index using, for example, a 'doughnut' mode beam:

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