Ultrafast Permittivity Engineering Enables Broadband Enhancement and Spatial Emission Control of Harmonic Generation in ZnO

Zhonghui Nie*, Kevin Murzyn, Leo Guery, Thomas J. van den Hooven, Peter M. Kraus*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Moderate efficiencies of nonlinear optical processes can be one of the challenges limiting even more widespread applications. Here we demonstrate a broadband and giant enhancement of nonlinear processes in ZnO through ultrafast permittivity engineering. A remarkable enhancement of the second and third harmonic generation of up to 2 orders of magnitude can be observed over a broadband range of driving wavelengths. Moreover, this nonlinearity enhancement is reversible with a recovery time of ∼120 fs. Additional experiments and simulations confirm that the observed enhancement originates from a permittivity change induced by the photocarrier population. Our results provide the opportunity to actively customize materials with a larger nonlinearity for nanophotonics on ultrafast time scales over broadband wavelength ranges. Utilizing this finding, we also demonstrate a relevant application, where a transient wave-guiding effect is induced by a donut-shaped photocarrier-excitation pulse, which both reduces the width of the spatial profile of harmonic emission below the diffraction limit and simultaneously increases its central emission strength.

Original languageEnglish
Pages (from-to)5084-5090
Number of pages7
JournalACS Photonics
Volume11
Issue number12
Early online date15 Nov 2024
DOIs
Publication statusPublished - 18 Dec 2024

Bibliographical note

Publisher Copyright:
© 2024 The Authors. Published by American Chemical Society.

Keywords

  • epsilon near zero
  • high harmonic generation
  • microscopy
  • Nonlinear optics
  • permittivity engineering
  • ultrafast modulation

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