Strategies to enhance THz harmonic generation combining multilayered, gated, and metamaterial-based architectures

Titelangaben

Maleki, Ali ; Heindl, Moritz ; Xin, Yongbao ; Boyd, Robert W. ; Herink, Georg ; Ménard, Jean-Michel:
Strategies to enhance THz harmonic generation combining multilayered, gated, and metamaterial-based architectures.
arxiv , 2024
DOI: https://doi.org/10.48550/arXiv.2405.17125

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Abstract

Graphene has unique properties paving the way for groundbreaking future applications. Its large
optical nonlinearity and ease of integration in devices notably makes it an ideal candidate to
become a key component for all-optical switching and frequency conversion applications. In the
terahertz (THz) region, various approaches have been independently demonstrated to optimize the
nonlinear effects in graphene, addressing a critical limitation arising from the atomically thin
interaction length. Here, we demonstrate sample architectures that combine strategies to enhance
THz nonlinearities in graphene-based structures. We achieve this by increasing the interaction
length through a multilayered design, controlling carrier density with an electrical gate, and
modulating the THz field spatial distribution with a metallic metasurface substrate. Our study
specifically investigates third harmonic generation (THG) using a table-top high-field THz source.
We measure THG enhancement factors exceeding thirty and propose architectures capable of
achieving a two-order-of-magnitude increase. These findings highlight the potential of engineered
graphene-based samples in advancing THz frequency conversion technologies for signal
processing and wireless communication applications