UCL Physics Society Talk

Phil is giving a talk the the UCL undergraduate Physics Society, Tue 02 Jun 15 titled "Pull, push, spin, squeeze: optical forces on microparticles."

Abstract:  In this talk I will explain how the interaction of laser light with matter can give rise to a force or torque that, if the particle is small enough, can have a significant effect on its motion.  I will then go on to describe a number of experiments from the UCL Optical Tweezers Group that use optical forces in a variety of experimental geometries (optical tweezers, optical fibre traps, optical binding) and applied to a range of different objects, including nanostructures and biological material.

Paper in J Opt Soc Am A

Our paper on the optical trapping force on a particle using a radially polarised beam focused by a "devil's vortex lens" has been published as Ruili Zhang, Ziyang Chen, Jixiong Pu and P. H. Jones, 'Radiation forces on a Rayleigh particles by highly focused radially polarized beams modulated by Devil's vortex lens', Journal of the Optical Society of America A 32 797-802 (2015).

From the abstract:  The intensity and the radiation forces acting on a Rayleigh particle near the focus of completely coherent radially polarized beams whose phase are modulated by a devil’s vortex-lens (DVL) are studied. The influence of the structure of a DVL on the radiation force distribution is analyzed. It is found by numerical simulations that the modulated beams show a clear advantage over the unmodulated highly focused radially polarized beams, as the modulated beam can simultaneously trap and manipulate the multiple Rayleigh particles, while the unmodulated beam can trap only one particle under the same condition.