Self-Induced Decay of Intense Laser Pulse into a Pair of Surface Plasmons

TL;DR

This paper theoretically demonstrates that intense femtosecond laser pulses incident on a metal surface can spontaneously decay into counter-propagating surface plasmon-polaritons, with implications for laser-induced surface structuring.

Contribution

It introduces a novel mechanism where laser-induced interference heats the medium, resonantly amplifying surface plasmons, explaining surface structure formation in a single pulse.

Findings

SPP decay occurs within 10-50 fs at typical laser fluences.

Interference heating causes periodic permittivity changes, amplifying SPPs.

Mechanism explains laser-induced periodic surface structures.

Abstract

We show theoretically that an intense femtosecond optical pulse incident normally on a metal surface tends to decay into a pair of counter-propagating surface plasmon-polaritons (SPPs). The interference field heats the medium periodically, which causes a periodic permittivity perturbation and resonantly amplifies the magnitudes of SPPs. The instability growth time is only 10-50 fs for typical metals at damaging laser fluences. This mechanism is promising for the interpretation of laser-induced periodic surface structures formation in a single-pulse pumping regime.