Near-Field Optical Tweezers Based On Nsom And Afm Probes

By applying the direct calculation of Maxwell stress tensor using finite difference time domain method, the feasibility of using a metal-coated fiber probe and using the combination of a near-field scanning optical microscopy (NSOM) probe and an atomic force microscopy (AFM) probe to create near-field optical tweezers is investigated. Numerical results indicate that these schemes are able to trap particles in the range of tens of nano-meters. In experiments 120 nm polystyrene particles are trapped in multi-circular shape with a minimum size of 400 nm, and the polystyrene cluster consisting of three polystyrene particles is obtained for the fabrication of stable polymer nano-structures.