Abstract-Electrically Controllable Molecularization of Terahertz Meta‐Atoms

Hyunseung Jung,   Jaemok Koo,   Eunah Heo,   Boeun Cho,   Chihun In,   Wonwoo Lee,   Hyunwoo Jo,  Jeong Ho Cho,   Hyunyong Choi,   Moon Sung Kang,  Hojin Lee,

https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201802760

Active control of metamaterial properties is critical for advanced terahertz (THz) applications. However, the tunability of THz properties, such as the resonance frequency and phase of the wave, remains challenging. Here, a new device design is provided for extensively tuning the resonance properties of THz metamaterials. Unlike previous approaches, the design is intended to control the electrical interconnections between the metallic unit structures of metamaterials. This strategy is referred to as the molecularization of the meta‐atoms and is accomplished by placing graphene bridges between the metallic unit structures whose conductivity is modulated by an electrolyte gating. Because of the scalable nature of the molecularization, the resonance frequency of the terahertz metamaterials can be tuned as a function of the number of meta‐atoms constituting a unit metamolecule. At the same time, the voltage‐controlled molecularization allows delicate control over the phase shift of the transmitted THz, without changing the high transmission of the materials significantly.

Abstract-Electrically Controllable Reconfiguration of Terahertz Meta-Atoms into Meta-Molecules

Hyunseung Jung, Jaemok Koo, Wonwoo Lee, Moon Sung Kang, and Hojin Lee

https://www.osapublishing.org/abstract.cfm?uri=CLEO_QELS-2018-FM3J.8

We report structural methodology for electrically switchable terahertz metamaterials between atom- and molecule-states by using limited conductance variation of graphene bridges. Based on experimental verification, we confirmed 39% of wide resonance tuning of terahertz metamaterials.

© 2018 The Author(s)

Abstract-Electromagnetically Induced Transparency Analogue by Self-Complementary Terahertz Meta-Atom

1. Hyunseung Jung¹, 
2. Chihun In², 
3. Hyunyong Choi² and
4. Hojin Lee^1,*

Article first published online: 19 JAN 2016

DOI: 10.1002/adom.201500620

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

http://onlinelibrary.wiley.com/doi/10.1002/adom.201500620/abstract

In the past years, many researchers have tried to realize the electromagnetically induced transparency (EIT) phenomena from the metamaterial arrays for the attractable applications such as slow light devices, novel optical communication systems, and nonlinear optical devices. Most of metamaterial enabled EIT analogues reported so far are based on the destructive interference between the bright and dark meta-atoms. Whether they are located on the same plane or off the plane, EIT-like properties can be achieved only by breaking the symmetry between the bright and dark meta-atoms. In this study, a novel self-complimentary terahertz meta-atom is developed by combining cut-wire resonators and its pseudo-complimentary pattern within a single meta-atom. From the measurement results, it is verified that the proposed meta-atom can exhibit EIT-like phenomenon within a single unit cell by controlling the focus of the electric field induced by the incident terahertz waves within the self-complimentary meta-atom cell as predicted by the numerical simulation as well as by the theoretical forced oscillation model.

Abstract-Anisotropy Modeling of Terahertz Metamaterials: Polarization Dependent Resonance Manipulation by Meta-Atom Cluster

Hyunseung Jung,

Chihun In,

Hyunyong Choi

& Hojin Lee

• http://www.nature.com/srep/2014/140609/srep05217/full/srep05217.html

Recently metamaterials have inspired worldwide researches due to their exotic properties in transmitting, reflecting, absorbing or refracting specific electromagnetic waves. Most metamaterials are known to have anisotropic properties, but existing anisotropy models are applicable only to a single meta-atom and its properties. Here we propose an anisotropy model for asymmetrical meta-atom clusters and their polarization dependency. The proposed anisotropic meta-atom clusters show a unique resonance property in which their frequencies can be altered for parallel polarization, but fixed to a single resonance frequency for perpendicular polarization. The proposed anisotropic metamaterials are expected to pave the way for novel optical systems.