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Optically mediated particle clearing using Airy wavepackets


The Airy wavepacket solution for a free particle exhibits propagation invariance and, surprisingly, acceleration transverse to the propagation direction1. Discovered as a solution of the free-particle Schrödinger equation, Airy wavepackets have been predicted2, and in a recent major step forward, realized3 in the optical domain, but have never been used in any application. In this Letter we demonstrate the first use of the Airy light beam in optical micromanipulation4,5. Based on the characteristic intensity pattern, the beam drags particles into the main intensity maximum, which guides particles vertically along a parabolic trajectory. This unusual property of Airy beams leads to a new feature in optical micromanipulation—the removal of particles and cells from a section of a sample chamber. We term this highly robust and efficient process ‘optically mediated particle clearing’, which enables novel microfluidic applications within the colloidal and biological sciences.

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Figure 1: The micrometre-scale ‘snowblower’ at work.
Figure 2: The clearing and guiding effect of an Airy beam.
Figure 3: Self-healing of Airy beams.
Figure 4: Self-healing of Airy beams, intuitively.


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The authors acknowledge support for this project from the UK Engineering and Physical Sciences and the University of St. Andrews. They also thank T. Čižmár for technical advice and support. K.D. is a Royal Society-Wolfson Merit Award holder.

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J.B. designed and performed the experiments and wrote the paper with support from the other authors. M.M. carried out the numerical simulations. K.D. planned the project. All of the authors participated in the analysis and discussion of the results.

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Correspondence to Kishan Dholakia.

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Baumgartl, J., Mazilu, M. & Dholakia, K. Optically mediated particle clearing using Airy wavepackets. Nature Photon 2, 675–678 (2008).

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