Nonlinear Photoluminescence in Gold Thin Films

Álvaro Rodríguez Echarri*, Fadil Iyikanat, Sergejs Boroviks, N. Asger Mortensen, Joel D. Cox, F. Javier García de Abajo*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Promising applications in photonics are driven by the ability to fabricate crystal-quality metal thin films of controlled thickness down to a few nanometers. In particular, these materials exhibit a highly nonlinear response to optical fields owing to the induced ultrafast electron dynamics, which is however poorly understood on such mesoscopic length scales. Here, we reveal a new mechanism that controls the nonlinear optical response of thin metallic films, dominated by ultrafast electronic heat transport when the thickness is sufficiently small. By experimentally and theoretically studying electronic transport in such materials, we explain the observed temporal evolution of photoluminescence in two-pulse correlation measurements that we report for crystalline gold flakes. Incorporating a first-principles description of the electronic band structure, we model electronic transport and find that ultrafast thermal dynamics plays a pivotal role in determining the strength and time-dependent characteristics of the nonlinear photoluminescence signal, which is largely influenced by the distribution of hot electrons and holes, subject to diffusion across the film as well as relaxation to lattice modes. Our findings introduce conceptually novel elements ruling the nonlinear optical response of nanoscale materials, while suggesting additional ways to control and leverage hot carrier distributions in metallic films.

Original languageEnglish
JournalACS Photonics
Volume10
Issue number8
Pages (from-to)2918–2929
ISSN2330-4022
DOIs
Publication statusPublished - 16. Aug 2023

Keywords

  • electronic structure
  • nanoscale thermal transport
  • nonlinear photoluminescence
  • nonlinear photonics
  • photoluminescence

Fingerprint

Dive into the research topics of 'Nonlinear Photoluminescence in Gold Thin Films'. Together they form a unique fingerprint.

Cite this