Simulation of Optical Nano-Manipulation with Metallic Single and Dual Probe Irradiated by Polarized Near-Field Laser

Genwang Wang,Haotian Long,Lijun Yang,Ye Ding,Yanchao Guan,Yang Wang,Xiwen Lu

doi:10.3390/app12020815

Abstract

Nano-manipulation technology, as a kind of “bottom-up” tool, has exhibited an excellent capacity in the field of measurement and fabrication on the nanoscale. Although variety manipulation methods based on probes and microscopes were proposed and widely used due to locating and imaging with high resolution, the development of non-contacted schemes for these methods is still indispensable to operate small objects without damage. However, optical manipulation, especially near-field trapping, is a perfect candidate for establishing brilliant manipulation systems. This paper reports about simulations on the electric and force fields at the tips of metallic probes irradiated by polarized laser outputted coming from a scanning near-field optical microscope probe. Distributions of electric and force field at the tip of a probe have proven that the polarized laser can induce nanoscale evanescent fields with high intensity, which arouse effective force to move nanoparticles. Moreover, schemes with dual probes are also presented and discussed in this paper. Simulation results indicate that different combinations of metallic probes and polarized lasers will provide diverse near-field and corresponding optical force. With the suitable direction of probes and polarization direction, the dual probe exhibits higher trapping force and wider effective wavelength range than a single probe. So, these results give more novel and promising selections for realizing optical manipulation in experiments, so that distinguished multi-functional manipulation systems can be developed.

Highlights

Since xenon atoms were successfully positioned and assembled with atomic precision [1], nano-manipulation technology, as a kind of “bottom-up” tool, has attracted wide attention in the fields of nano-measurement, nano-fabrication, nano-optics, nano-robot, and so on [2–5]
This paper investigates the near-field and corresponding optical force around metallic single and dual probes irradiated by the polarized laser
The distributions of electric fields around the tip of the single probe demonstrate that a polarized laser can induce nanoscale evanescent fields with high intensity, which are essential for optical manipulation

Summary

Introduction

Since xenon atoms were successfully positioned and assembled with atomic precision [1], nano-manipulation technology, as a kind of “bottom-up” tool, has attracted wide attention in the fields of nano-measurement, nano-fabrication, nano-optics, nano-robot, and so on [2–5]. Among various nano-manipulation methods, the most widespread is probe manipulation based on high-resolution microscopes, including atomic force microscope (AFM), scanning tunneling microscope (STM), scanning electron microscope (SEM), and transmission electron microscope (TEM) [6–9]. With images feedback of targets, these systems use probes, which are carried by manipulators with nanoscale resolution of movement, as end-effectors to push, pick, stretch, place, and bend nanomaterials. The manipulation mechanism of this method is mainly based on the control of mechanical forces (e.g., contact force, Van der Waals force, friction) between probes, objects, and substrates [10,11]. Due to the convenience of locating and imaging, this method exhibits outstanding manipulation capacity, and enormous potential in the application of nanomaterials, like tuning electrical and optical properties, constructing nanostructure, and even fabricating nano-devices. Two-dimensional materials were folded and unfolded precisely by the STM-based manipulation system to improve electrical and quantum properties [14]

Methods

Results

Conclusion