Effect of the probe location on the absorption by an array of gold nano-particles on a dielectric surface

- Local absorption mechanism in near field coupling between an array of gold nanoparticles and Si AFM tip is studied.
- 2D array configurations with varied spacing of nanoparticles and AFM tip positions are evaluated for the absorption efficiency of central particle.
- The tip positions maximizing the absorption of central particle relative to the propagation direction of the evanescent wave are identified for each spacing case.
- Optimal particle spacing is predicted for 9 gold nanoparticles subjected to TM evanescent wave.
- Vectorized version of DDA-SI (DDA-SI-v) is utilized for the analysis.

Effect of silicon atomic force microscope probe position and particle spacing on the local absorption of an array of gold nanoparticles placed over a dielectric borosilicate glass surface are evaluated. An improved, vectorized version of discrete dipole approximation coupled with surface interactions is employed throughout the study. It is shown that surface evanescent waves interacting with the system of nanoparticles and atomic force microscope probe result in a near-field coupling between them. This coupling can enhance or reduce the local absorption by the nanoparticles depending on the position of atomic force microscope tip in three-dimensional space and direction of propagation of the surface evanescent wave. The position of the atomic force microscope's tip and spacing that maximize the absorption are identified. This concept can be used for selective heating of nanoparticles placed over a surface that enables precision manufacturing at nanometer scales.