Optical trapping force combining an optical fiber probe and an AFM metallic probe

A high-resolution optical trapping and manipulating scheme combining an optical fiber probe and an AFM metallic probe is proposed. This scheme is based on the combination of evanescent illumination and light scattering at the metallic probe apex, which shapes the optical field into a localized, three-dimensional optical trap. Detailed simulations of the electromagnetic fields in composite area and the resulting forces are described the methods of Maxwell stress tensor and three-dimensional FDTD. Calculations show that the scheme is able to overcome the disturbance of other forces to trap a polystyrene particle of up to 10nm in radius with lower laser intensity (∼1040W/mm ²) than that required by conventional optical tweezers (∼10 ⁵W/mm²). Based on the discussion of high manipulating efficiency dependent on system parameters and the implementing procedure, the scheme allowing for effective manipulation of nano-particles opens a way for research on single nano-particle area.