Delayed optical nonlinearity of thin metal films

TL;DR

This paper models the delayed optical nonlinearity in thin metal films, specifically gold, using an ab initio approach based on an improved two-temperature model, validated through ultrafast pump-probe experiments.

Contribution

It introduces a novel ab initio model for the delayed cubic nonlinearity in thin metal films, enhancing understanding of thermal nonlinear effects.

Findings

Model accurately predicts nonlinear response in gold films.

Validation with ultrafast pump-probe experiments confirms model reliability.

Highlights the thermal origin of large nonlinear susceptibilities in metals.

Abstract

Metals typically have very large nonlinear susceptibilities, whose origin is mainly of thermal character. We model the cubic nonlinearity of thin metal films by means of a delayed response derived \textit{ab initio} from an improved version of the classic two temperature model. We validate our model by comparison with ultrafast pump-probe experiments on gold films.