Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	Graphene Nanosheet-Gold Nanopatch Metasurfaces for Nonlinear Response at THz Frequencies
Δημιουργός/Συγγραφέας:	Theodosi, Anna Otoo, Isaac Appiah Koulouklidis, Anastasios D Matthaiakakis, Nikolaos [EL] Κακαράντζας, Γεώργιος[EN] Kakarantzas, George Mustonen, Petri Lipsanen, Harri Fedorov, Georgy Liontos, Ioannis Tzortzakis, Stelios Kuzhir, Polina Kafesaki, Maria [EL] Τσιλιπάκος Οδυσσέας[EN] Tsilipakos, Odysseas
Ημερομηνία:	2025-12-26
Γλώσσα:	Αγγλικά
ISSN:	2574-0970 2574-0970
DOI:	10.1021/acsanm.5c04665
Άλλο:	41476678
Περίληψη:	Graphene's exceptional nonlinear optical properties combined with resonant photonic structures offer a promising pathway for efficient nonlinear applications at terahertz (THz) frequencies. In this work, we propose and demonstrate a fabrication-friendly hybrid nonlinear metasurface composed of gold patches integrated with uniform graphene, circumventing the need for complex graphene patterning. The structure supports strong localized resonances that enhance nonlinear interactions. By exploiting resonant enhancement at both the fundamental and third harmonic frequencies, we predict via simulations third-harmonic generation efficiencies as high as -15 dB (3.2%) under continuous-wave excitation at modest intensities (0.1 MW/cm2). The metasurface is fabricated via electron-beam lithography and experimentally characterized under pulsed excitation using THz time-domain spectroscopy. The broadband excitation spectrum prevents unambiguous isolation of a third-harmonic signal; however, we experimentally observe pronounced nonlinear frequency shifts up to 0.5 THz (12.5% fractional change), driven by self-phase modulation, consistent with simulation results. Our findings highlight the potential of tailored graphene-based metasurfaces for efficient nonlinear THz photonic devices.
Τίτλος πηγής δημοσίευσης:	ACS applied nano materials
Τόμος/Κεφάλαιο:	8
Τεύχος:	51
Θεματική Κατηγορία:	[EL] Νανοτεχνολογία[EN] Nanotechnology [EL] Εφαρμοσμένη οπτική. Φωτονική[EN] Applied optics. Photonics
Λέξεις-Κλειδιά:	doubly resonant enhancement metamaterials nonlinear frequency shift nonlinear optics self-phase modulation third harmonic generation
Κάτοχος πνευματικών δικαιωμάτων:	© 2025 The Authors. Published by American Chemical Society.
Όροι και προϋποθέσεις δικαιωμάτων:	This publication is licensed under CC-BY-NC-ND 4.0 .
Ηλεκτρονική διεύθυνση στον εκδότη (link):	https://doi.org/10.1021/acsanm.5c04665
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο