Terahertz 2-4 Decoder Based on A Dual-Peak Electromagnetically Induced Transparency Metasurface

Terahertz (THz) technology has shown great potential for applications in communication, sensing, and information processing due to its unique frequency range and properties. However, the development of compact and efficient THz logic devices poses a significant challenge. In this work, we propose a terahertz (THz) 2-4 decoder based on a graphene-integrated dual-peak electromagnetically induced transparency (EIT) metasurface. This decoder is designed to translate 2 - bit input signals (00, 01, 10, 11) into four distinct output states (S0, S1, S2, S3), each with a unique transmission spectrum. It accomplishes this by independently modulating two EIT windows through the graphene, whose Fermi energy (and consequently, the conductivity) can be precisely adjusted by applying input voltage biases. Given the narrow-gap-resonator structural characteristics, a relatively low Fermi energy (up to 0.6 eV) can effectively modulate the damping rates and coupling coefficients between the bright and dark modes. This, in turn, allows for the selective activation of the two EIT peaks to perform logic decoding. Finite-difference time-domain (FDTD) simulations and a coupled oscillator model based theoretical analysis both validate the decoder’s performance. The proposed THz decoder provides a way to design compact EIT logic devices, which may be implemented with other integrated system to achieve broad THz application field.