Surface plasmon effects on pore formation around an array of rods on a surface irradiated by a pulsed electromagnetic wave

This study investigates fluid flow, heat transfer, and energy generation induced by surface plasmon resonance in an array of nanorods (NRs) on a metal surface irradiated by a laser in the transverse magnetic mode. Surface plasmons are electromagnetic waves that propagate along the interface between two media, resulting in both distributed and localized heat input on the surface. The heating, melting, and solidification behaviors of NRs or nanoparticles are crucial for understanding additive manufacturing, plasma processing, and various nanotechnology applications. Simulations performed with COMSOL software, which solve the transport and electromagnetic equations, reveal the dependence of surface plasmon or energy absorption on the incident angle, the width and frequency of the laser, and the number of NRs on the metal surface. Oscillations of surface plasmons lead to initial melting at distinct locations, with the peak surface temperature approximately coinciding with the peaks of energy generation. A secondary energy-generation peak, caused by the penetration of a strong electric field intensity, appears near the triple-phase line of the first NR. The molten pools due to thermocapillary flow subsequently expand and coalesce, enclosing voids and forming pores that transition from deformed to cylindrical shapes between the NRs.