Analysis of the Nanoscale Manipulation Using Near-Field Optical Tweezers Combined with AFM Probe

Abstract

In recent years, optical manipulators based on forces exerted by enhanced evanescent field close to near-field optical probes have provided the access to nonintrusive manipulation of nanometric particles. However, the manipulation capability is restricted to the intensity enhancement of the probe tip due to low emitting efficiency. Here a near-field optical trapping scheme using the combination of an optical fiber probe and an AFM metallic probe is developed theoretically. Calculations are made to analyze the field distributions including tip interaction and the trapping forces in the near-field region by applying a direct calculation of Maxwell stress tensor using three-dimensional FDTD. The results show that the scheme is able to trap particle at the nanoscale with lower laser intensity than that required by conventional near-field optical tweezers.