Selective optical trapping based on strong plasmonic coupling between gold nanorods and slab

Y. J. Zheng, H. Liu, S. M. Wang, T. Li, J. X. Cao, L. Li, C. Zhu, Y. Wang, S. N. Zhu, and X. Zhang

A resonance plasmon mode is formed between a gold nanorod and an infinite slab in infrared range, with local electric field enhancement factor over 40. A strong optical attractive force is exerted on the rod by the slab at resonance frequency. Based on Maxwell stress tensor method and numerical simulations, the optical force was calculated to be over 2.0 nN/(mW/μm2). For a fixed incident wavelength, the enhanced optical force is obtained only for the rods with particular length when the diameter is fixed. This strong optical force could be used as a possible selective optical trapping technique in the future.

DOI