All-optically controlled holographic plasmonic vortex array for multiple metallic particles manipulation.

Due to the sub-diffraction-limited size and giant field enhancement, plasmonic tweezers have a natural advantage in trapping metallic particles. However, the strict excitation condition makes it difficult to generate an arbitrary plasmonic field in a controllable manner, thus narrowing its practical applications. Here, we propose an all-optical plasmonic field shaping method based on a digital holographic algorithm and generate plasmonic vortex arrays with controllable spot numbers, spatial location, and topological charge. Our experimental results demonstrate that multiple gold particles can be stably trapped and synchronously rotated in the vortex arrays, and the particles' kinestate can be dynamically switched. The proposed holographic plasmonic vortex tweezers are suitable for a broadband particle trapping, and this method can be generalized to other surface electromagnetic waves like Bloch surface wave.