A dual functional tunable terahertz metamaterial absorber based on vanadium dioxide

Area of Science:

• Metamaterials
• Terahertz Technology
• Optoelectronics

Background:

• Metamaterial absorbers (MMAs) are crucial for controlling electromagnetic waves.
• Vanadium dioxide (VO2) exhibits tunable conductivity, enabling switchable device functionalities.
• Achieving dual-mode absorption (broadband and narrowband) in a single MMA is challenging.

Purpose of the Study:

• To propose and analyze a dual-functional switchable metamaterial absorber (MMA) based on vanadium dioxide (VO2).
• To demonstrate flexible switching between broadband and four-band absorption by tuning VO2 conductivity.
• To explore the potential applications of this switchable MMA in stealth technology and thermal emitters.

Main Methods:

• Numerical simulations were employed to analyze the MMA's absorption characteristics.
• The device's performance was evaluated under varying VO2 conductivity states (metal and insulator phases).
• Impedance matching theory was used to understand the absorption mechanism, and structural parameter influence was investigated.

Main Results:

• The MMA achieved over 90% absorption in the 3.36-6.98 THz range in broadband mode (VO2 metal phase).
• In narrowband mode (VO2 insulator phase), high absorption rates (up to 99.7%) were observed at specific frequencies (2.39, 2.83, 3.84, 4.61 THz).
• The absorber demonstrated polarization insensitivity and wide-angle performance for both transverse electric (TE) and transverse magnetic (TM) waves.

Conclusions:

• The proposed MMA successfully integrates broadband and narrowband absorption functionalities through simple VO2 conductivity tuning.
• The device exhibits excellent performance, including polarization insensitivity and wide-angle absorption.
• This switchable MMA offers significant potential for applications in stealth technology, thermal emitters, and as a high-sensitivity sensor.