The near-field enhancement and localized surface plasmon resonance (LSPR) on the core-shell noble metal nanostructure surfaces are widely studied for various biomedical applications. However, the study of the optical properties of new plasmonic non-spherical nanostructures is less explored. This numerical study quantifies the optical properties of spherical and non-spherical (prolate and oblate) dimer nanostructures by introducing finite element modelling in COMSOL Multiphysics. The surface plasmon resonance peaks of gold nanostructures should be understood and controlled for use in biological applications such as photothermal therapy and drug delivery. In this study, we find that non-spherical prolate and oblate gold dimers give excellent tunability in a wide range of biological windows. The electromagnetic field enhancement and surface plasmon resonance peak can be tuned by varying the aspect ratio of non-spherical nanostructures, the refractive index of the surrounding medium, shell thickness, and the distance of separation between nanostructures. The absorption spectra exhibit considerably greater dependency on the aspect ratio and refractive index than the shell thickness and separation distance. These results may be essential for applying the spherical and non-spherical nanostructures to various absorption-based applications.

This study presents a comprehensive numerical investigation of the photothermal response of core–shell gold nanoshell (CGNS) and gold nanorod (CGNR) under femtosecond (fs) laser pulse irradiation.

New opportunities for applications in areas including photothermal therapy (PTT), biomedical imaging, and energy conversion have been made possible by advancements in nanoparticle technology. Understanding the thermal and fluidic behavior of these nanoparticles is crucial for their effective utilization. In this computational study, numerical simulations are used to examine the convective velocities connected to various gold nanoparticle (AuNP) morphologies, including nanorods, nanoshells, and nanodiscs. Our findings clearly demonstrate that nanorods have the maximum convective velocity of 91 µm/s, making them the most attractive choice for applications needing excellent thermal and fluidic performance. Additionally, we investigate the relationship between bubble diameter and convective velocity in the vicinity of gold nanorods and nanoshells. Our findings indicate that as the bubble diameter expands to 10 μm, there is a noticeable surge in convective velocity, which eventually plateaus. Furthermore, we explore the impact of shell thickness and core radius on convective velocity. A decrease in shell thickness and an increase in core radius were found to significantly enhance convective velocity, with an optimal core radius of 38 nm identified for peak performance. These findings provide vital information for the design optimization of AuNPs, notably for PTT and photoacoustic (PA) imaging, two fields where precise control of thermal and fluidic processes is essential.