On-Chip Optical Trapping with High NA Metasurfaces
Photonic metasurfaces can be used to create strongly focused beams for optical trapping applications. Here, we design and fabricate holographic metasurfaces with numerical aperture up to 1.2, and trapping stiffness greater than 400 pN/µm/W, which perform as well as a microscope objective with a comparable numerical aperture. In this work, we analyze how the trapping performance depends on the metasurface dimension, down to areas as small as 0.001 mm2. Finally, we demonstrate the photonic metasurfaces can create multi-site optical tweezers, for the trapping of extended objects, like photonic membranes.