Multifunctional chip-scale plasmonic optical tweezers enabled by a polarization- and wavelength-dependent metasurface.

The ability of surface plasmons to confine light at a subwavelength scale enables new perspectives and opportunities in the field of nanotechnology. Making use of this unique advantage, plasmonic trapping techniques have been developed to tackle new challenges in a wide range of areas from physics to biology. However, it is still a challenge to achieve multifunctional chip-scale manipulation of small particles in a single plasmonic device. Here, we proposed a polarization- and wavelength-dependent plasmonic metasurface to realize multifunctional plasmonic optical tweezers. By fully utilizing the polarization and wavelength of light, it is shown that different kinds of SPP fields can be generated, which leads to integration of more than four optical manipulation functions, including plasmonic trapping as well as plasmonic spanner that can control both the rotation direction and radius of trapped particles. Furthermore, the metasurface also enables double-well optical trapping under linear polarization incidence. The proposed multifunctional metasurface facilitates diverse manipulation, which may open up new opportunities in biology, photonics, sensing, and related fields.