Tunable triple-broadband terahertz metamaterial absorber using a single VO2 circular ring

Ri, Kwang-Jin; Kim, Jin-Song; Kim, Jin-Hak; Ri, Chung-Ho

doi:10.1016/j.optcom.2023.129573

Cited by 12 publications

(2 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They can alter absorption frequencies within a fixed frequency range and control the absorber's functionality. Active absorbers often incorporate adjustable materials [22][23][24][25][26], diodes [20,21], mechanical structures [27,28], or flexible materials [29,30]. This allows for tunability through temperature, electronics, mechanical deformation, and other means.…”

Section: Introductionmentioning

confidence: 99%

Adaptive impedance matching in microwave and terahertz metamaterial absorbers using PIN diodes and GaN HEMTs

Liu,

Ibrahim,

Majid

et al. 2024

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

Metamaterial absorbers allow electromagnetic waves to be converted into heat energy based on impedance matching. However, passive metamaterial absorbers exhibit fixed absorption characteristics, limiting their flexibility. This work demonstrates tunable microwave and terahertz absorbers by integrating adjustable resistors into the metamaterial units. First, a microwave absorber from 1-5 GHz was designed by embedding PIN diodes with voltage-controlled resistance. Calculations, simulations, and measurements verified two separate absorption peaks over 90% when optimized to a resistance of 250 Ω. The absorption frequencies shifted based on the resistor tuning. Building on this, a terahertz absorber was modeled by substituting gallium nitride high electron mobility transistors (GaN HEMTs) as the adjustable resistor component. The GaN HEMTs were controlled by an integrated gate electrode to modify the two-dimensional electron gas density, allowing resistance changes without external voltage terminals. Simulations revealed two absorption peaks exceeding 90% absorption at 0.34 THz and 1.06 THz by adjusting the equivalent resistance from 180 Ω to 380 Ω, and the tunable resistance is verified by DC measurement of single GaN HEMT in the unit. This work demonstrates how integrating adjustable resistors enables dynamic control over the absorption frequencies and bandwidths of metamaterial absorbers. The proposed geometries provide blueprints for tunable microwave and terahertz absorbers.

show abstract

Section: Introductionmentioning

confidence: 99%

Adaptive impedance matching in microwave and terahertz metamaterial absorbers using PIN diodes and GaN HEMTs

Liu,

Ibrahim,

Majid

et al. 2024

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

show abstract

“…Therefore, researchers have utilized phase change materials such as VO 2 and graphene, among others, to engineer terahertz devices with multifunctionality. Vanadium dioxide (VO 2 ) serves as a foundational material undergoing a remarkable transition from an insulating phase to a metallic phase at 68 • C [40][41][42][43][44][45]. This phase transition results in a significant alteration in electrical conductivity.…”

Section: Introductionmentioning

confidence: 99%

Conversion and Active Control between BIC and Absorber in Terahertz Metasurface

Xi,

Chen

2024

Photonics

View full text Add to dashboard Cite

A multifunctional switchable metamaterial device based on graphene, a gold layer, polyimide, vanadiµm dioxide (VO2), and the sapphire substrate is designed in this paper. The top layer consists of a gold wire, graphene, and two split-ring resonators with the same parameters. By adjusting the Fermi level of graphene, the regulation of BIC and quasi-BIC is realized, and the conversion between BIC and absorber is realized by adjusting the conductivity of VO2. When the device is converted into a wave-absorbing device with single-band absorption characteristics, the Fermi level of graphene at this time is 0.001 eV, the absorption peak at 0.820 THz is higher than 99.5%, and when the Fermi level of regulated graphene is 1 eV, the absorption peak at 0.667 THz is also higher than 99.5%. The peak frequency of the device is 0.640 THz when it converts to quasi-BIC. To the best of our knowledge, this is the first time that the conversion and regulation of BIC and absorber have been achieved using these two phase change materials. Moreover, by adjusting the parameters of the metamaterial structure, the working efficiency and frequency of BIC and absorber can be dynamically adjusted. The electric field distribution and surface current of metamaterials are further studied, and the physical mechanism of effective absorption and BIC is discussed. These results show that the metamaterials proposed in this paper have many advantages, such as terahertz absorption, BIC, and active device control, and are of great significance for developing terahertz multifunctional devices.

show abstract