Controllable Trapping of Nanowires Using a Symmetric Slot Waveguide

Abstract

A controllable trapping method based on using a symmetric slot waveguide is proposed. The structure is composed of a subwavelength slot formed between two adjacent thin metallic films embedded in an infinite homogeneous dielectric medium. Generated near-field components interact with a nanowire and exert net force on it. Green’s function surface integral equation method is exploited for numerical calculation of the electric and the magnetic fields and, consequently, the radiation force acting on the nanowire. Casimir force is also obtained by calculating Maxwell stress tensor and using fluctuation–dissipation theorem. Results illustrate that depending on the width and the thickness of the slot, the radiation force and, consequently, the position of the stable equilibrium point change. By controlling the phase difference of the incident SPP waves it is possible to trap or release the nanowire at a specified position. In addition, results reveal that Casimir force moves nanowires toward the center of the slot and is maximum at the entrance of the slot with magnitude depending on the width and thickness of the slot.