Influence of surface plasmon polaritons on laser energy absorption and structuring of surfaces

TL;DR

This paper investigates how surface plasmon polaritons influence laser energy absorption and surface structuring during ultrashort laser pulses, providing an analytical model to improve understanding of surface modifications for nanophotonics.

Contribution

It introduces an analytical source term model for SPP excitation at a dielectric-metal interface during ultrashort laser irradiation, enhancing predictive capabilities for surface structuring.

Findings

Quantifies the effect of laser parameters on energy absorption in gold.

Provides an analytical framework for SPP excitation at step edges.

Facilitates controlled surface structuring for nanophotonic applications.

Abstract

The accurate calculation of laser energy absorption during femto- or picosecond laser pulse experiments is very important for the description of the formation of periodic surface structures. On a rough material surface, a crack or a step edge, ultrashort laser pulses can excite surface plasmon polaritons (SPP), i.e. surface plasmons coupled to a laser-electromagnetic wave. The interference of such plasmon wave and the incoming pulse leads to a periodic modulation of the deposited laser energy on the surface of the sample. In the present work, within the frames of a Two Temperature Model we propose the analytical form of the source term, which takes into account SPP excited at a step edge of a dielectric-metal interface upon irradiation of an ultrashort laser pulse at normal incidence. The influence of the laser pulse parameters on energy absorption is quantified for the example of gold. This result can be used for nanophotonic applications and for the theoretical investigation of the evolution of electronic and lattice temperatures and, therefore, of the formation of surfaces with predestined properties under controlled conditions.