Enhancing local absorption within a gold nano-sphere on a dielectric surface under an AFM probe

- Plasmonic coupling between solid or core-shell nanoparticles, dielectric surface and Si AFM tip is investigated for achieving localized heating for nano-manufacturing.
- Absorption efficiency enhancement limits for core-shell and solid nanoparticles are identified using an AFM tip for surface evanescent wave heating.
- The effect of tip location, relative to surface wave direction is outlined, identifying optimal locations, and heat absorption distribution over core-shell and solid nanoparticles.
- While using a Si AFM tip enhances absorption, using a dielectric core result in further enhancement in absorption with a more uniform distribution.
- DDA-SI-v developed by vectorizing the formulations of DDA-SI for improved computational efficiency.

This study considers enhancing localized absorption by a gold nanoparticle (NP) placed over a substrate where an atomic force microscope (AFM) tip is in close proximity of the particle. The gold NP and AFM tip are interacting with a surface evanescent wave, resulting a near-field coupling between the tip and NP and consequently enhances the absorption. This concept can be used for selective heating of NPs placed over a surface that enables precise manufacturing at nanometer scales. Different tip positions are considered to identify the optimal tip location and the corresponding enhancement limits. The effects of these interactions on the absorption profiles of dielectric core/gold shell NPs are also studied. It is observed that using core-shell nanoparticles with a dielectric core leads to further enhancement of the absorption efficiency and a more uniform distribution of absorption over the shell. Discrete dipole approximation coupled with surface interactions (DDA-SI) is employed throughout the study, and it is vectorized to improve its computational efficiency.