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arXiv · 1611.00638

Tomographic active optical trapping of arbitrarily shaped objects by exploiting 3-D refractive index maps

Kyoohyun Kim·YongKeun Park
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Abstract

Optical trapping can be used to manipulate the three-dimensional (3-D) motion of spherical particles based on the simple prediction of optical forces and the responding motion of samples. However, controlling the 3-D behaviour of non-spherical particles with arbitrary orientations is extremely challenging, due to experimental difficulties and the extensive computations. Here, we achieved the real-time optical control of arbitrarily shaped particles by combining the wavefront shaping of a trapping beam and measurements of the 3-D refractive index (RI) distribution of samples. Engineering the 3-D light field distribution of a trapping beam based on the measured 3-D RI map of samples generates a light mould, which can be used to manipulate colloidal and biological samples which have arbitrary orientations and/or shapes. The present method provides stable control of the orientation and assembly of arbitrarily shaped particles without knowing a priori information about the sample geometry. The proposed method can be directly applied in biophotonics and soft matter physics.

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Kyoohyun Kim, YongKeun Park. 2016-11-02. Tomographic active optical trapping of arbitrarily shaped objects by exploiting 3-D refractive index maps. https://doi.org/10.1038/ncomms15340

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