High‐harmonic generation from subwavelength silicon films
Recent years have witnessed significant developments in the study of nonlinear properties of various materials at the nanoscale. Often, experimental results on harmonic generation are reported without the benefit of suitable theoretical models that allow assessment of conversion efficiencies compared to the material's intrinsic properties. Here, we report experimental observations of <i>even and odd harmonics up to the 7</i>th, generated from a suspended subwavelength silicon film resonant in the UV range at 210 nm, the current limit of our detection system, using peak power densities of order 3 TW/cm<sup>2</sup>. We also highlight the time-varying properties of the dielectric function of silicon, which exhibits large changes under intense illumination. We explain the experimental data with a time domain, hydrodynamic-Maxwell approach broadly applicable to most optical materials. Our approach accounts simultaneously for surface and magnetic nonlinearities that generate <i>even optical harmonics</i>, as well as linear and nonlinear material dispersions beyond the third order to account for <i>odd optical harmonics</i>, plasma formation, and a phase locking mechanism that makes the generation of high harmonics possible deep into the UV range, where semiconductors like silicon start operating in a metallic regime.
Authors
- Wallace Jaffray (ORCID: https://orcid.org/0000-0001-7992-5193)
- Kent A. Hallman (ORCID: https://orcid.org/0000-0002-6078-8763)
- C. Cojocaru (ORCID: https://orcid.org/0000-0002-5244-8427)
- Yuri S. Kivshar (ORCID: https://orcid.org/0000-0002-3410-812X)
- Domenico de Ceglia (ORCID: https://orcid.org/0000-0001-5736-6298)
- S. Mukhopadhyay (ORCID: https://orcid.org/0000-0001-6070-864X)
- Marcello Ferrera (ORCID: https://orcid.org/0000-0003-4479-5127)
- J. Trull (ORCID: https://orcid.org/0000-0002-5850-088X)
- Maria Antonietta Vincenti (ORCID: https://orcid.org/0000-0001-6698-2973)
- Federico Belli (ORCID: https://orcid.org/0000-0002-2560-3428)
- Michael Scalora (ORCID: https://orcid.org/0000-0001-9559-7601)
- Sven Stengel (ORCID: https://orcid.org/0009-0006-2111-9061)
- Neşet Aközbek
Institutions
- Australian National University (AU)
- U.S. Army Aviation and Missile Command (US)
- United States Army Combat Capabilities Development Command (US)
- Heriot-Watt University (GB)
- PeopleTec (United States) (US)
- U.S. Army Combat Capabilities Development Command Aviation & Missile Center
- University of Brescia (IT)
- U.S. Army Space and Missile Defense Command (US)
- Universitat Politècnica de Catalunya (ES)
Publication Details
- Journal
- Nanophotonics
- Published
- 2025-01-16
- DOI
- https://doi.org/10.1515/nanoph-2024-0468
- Citations
- 4
- Primary Topic
- Photonic and Optical Devices
- Type
- article
- Field-Weighted Citation Impact
- 2.92
Funders
- North Atlantic Treaty Organization
- Ministero dell'Università e della Ricerca
- Engineering and Physical Sciences Research Council
- Australian Research Council
- Agencia Estatal de Investigación
- Air Force Office of Scientific Research
- Army Research Office
- Army Research Laboratory
- European Office of Aerospace Research and Development