Geometric tailoring of plasmonic nanotips for atom traps

We theoretically analyzed a scheme for optical trapping of neutral atoms by plasmonic nanotips. An analytic quasistatic model was developed for studying the requirements on geometry and material parameters needed for a successful trap generation. We then used the numerical solution of Maxwell's equations to study different types of tips and realized optical trapping potentials at distances of up to 90 nm away from the tip apex. A dipole approximation of numerical results is presented, allowing for capturing essential trap characteristics in a simple form. Finally, we analyze scattering rates, trap characteristics, and heating of an exemplary nanotip, revealing the importance of heat dissipation for the considered structures.