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Active Control of Terahertz Transmission via Humidity-Responsive Swelling of Submicron Poly(vinyl alcohol)-Coated Nanoresonators

delete2026-06-12
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PRE
AI
H
Hyoung-Taek Lee
J
Jaekyung Kim
H
Hoyeol Lee
S
Seokho Lee
H
Hyeong‐Ryeol Park
H
Hee Jun Shin
J
Junsuk Rho *
DOI:10.1021/acs.nanolett.6c01713delete
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Abstract

Abstract

En 中文
This study demonstrates active control of terahertz (THz) transmission by exploiting the humidity-driven swelling of a submicron poly(vinyl alcohol) (PVA) film integrated with metallic nanoresonators. Conventional THz modulators typically require bulk-like membranes tens of micrometers thick to compensate for weak light–matter interaction, which inevitably results in slow, diffusion-limited response times. In contrast, our approach utilizes field confinement near nanometer gaps to achieve high modulation depth with an ultrathin layer, offering a potential route to high-speed operation. Under 90% relative humidity, the 193 nm PVA film swells to 380 nm, exhibiting a rapid response time of 373 ms─nearly three times faster than 1.25 μm films. The hybrid structure achieves a 13.6% transmission modulation, driven by a localized dielectric transition at electric-field hot-spots. These findings provide a robust strategy for high-performance THz metasurfaces that bypass the traditional trade-off between modulation depth and response speed.
Keywords:
Absorption
Humidity
Layers
Metamaterials
Metasurfaces
terahertz
nanophotonics
nanoresonator
hydrogel
humidity-driven swelling
active control

Journal

Nano Letters cover
Nano Letters
IF:
9.1
Papers:
2.7W
Citations:
16.5W

Organization

P
POSTECH
Scholars:
925
Papers: 378
Citations: 7
P
pohang university of science and technology
Scholars:
549
Papers: 194
Citations: 0
U
ulsan national institute of science and technology
Scholars:
1.2K
Papers: 443
Citations: 2
Cited Papers

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