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Kim, Dai-Sik
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Augmented All-Optical Active Terahertz Device Using Graphene-Based Metasurface

DC Field Value Language Choi, Geunchang ko Chau, Tuan Khanh ko Hong, Sung Ju ko Kim, Dasom ko Kim, Sung Hyuk ko Kim, Dai-Sik ko Suh, Dongseok ko Bahk, Young-Mi ko Jeong, Mun Seok ko 2021-07-15T07:40:19Z - 2021-06-08 ko 2021-08 ko
dc.identifier.citation ADVANCED OPTICAL MATERIALS, v.9, no.16, pp.2100462 ko
dc.identifier.issn 2195-1071 ko
dc.identifier.uri -
dc.description.abstract Photo-excited graphene has a positive (semiconductor-like) or negative (metal-like) response depending on the Fermi level, which is tuned by gate control, doping, and growth. Both negative and positive photoconductive responses have a potential application as an ultrafast optical modulator in the control of light transmission. However, it is challenging to achieve a high on/off ratio in the photo-excited graphene because of a small absorption of electromagnetic waves and a limitation of photo-induced conductivity change. Here, the negative-type high on/off ratio and ultrafast terahertz modulation are experimentally demonstrated using graphene/metal nanoslot antennas. When the graphene covers the nanoslot antennas, the terahertz waves are completely blocked (off-state). This perfect extinction results from the enhanced intraband absorption in graphene by strong localized fields near the nanogap. However, once the optical pump is applied to the graphene/nanoslot antennas, terahertz transmission becomes recovered resonantly (on-state) due to the photo-induced transparency of graphene that leads to a distinctive modulation from off- to on-resonance. Furthermore, the fast carrier relaxation induced by strong terahertz field-driven carrier redistribution is responsible for the faster modulation of transient terahertz transmission. The results will open up pathways toward negative-response terahertz modulation applications with high on/off ratio and ultrafast time scale. ko
dc.language 영어 ko
dc.publisher WILEY-V C H VERLAG GMBH ko
dc.title Augmented All-Optical Active Terahertz Device Using Graphene-Based Metasurface ko
dc.type ARTICLE ko
dc.identifier.scopusid 2-s2.0-85106277365 ko
dc.identifier.wosid 000653105100001 ko
dc.type.rims ART ko
dc.identifier.doi 10.1002/adom.202100462 ko
dc.identifier.url ko
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