Adiabatic Frequency Conversion Using a Time-Varying Epsilon-Near-Zero Metasurface.
Nano Lett
; 21(14): 5907-5913, 2021 07 28.
Article
em En
| MEDLINE
| ID: mdl-34251831
ABSTRACT
A time-dependent change in the refractive index of a material leads to a change in the frequency of an optical beam passing through that medium. Here, we experimentally demonstrate that this effect-known as adiabatic frequency conversion (AFC)-can be significantly enhanced by a nonlinear epsilon-near-zero-based (ENZ-based) plasmonic metasurface. Specifically, by using a 63-nm-thick metasurface, we demonstrate a large, tunable, and broadband frequency shift of up to â¼11.2 THz with a pump intensity of 4 GW/cm2. Our results represent a decrease of â¼10 times in device thickness and 120 times in pump peak intensity compared with the cases of bare, thicker ENZ materials for the similar amount of frequency shift. Our findings might potentially provide insights for designing efficient time-varying metasurfaces for the manipulation of ultrafast pulses.
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MEDLINE
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En
Ano de publicação:
2021
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Article