A broadband, tunable, and angle-insensitive terahertz absorber based on a monolayer MoS ₂ “C” – shaped metasurface

This numerical simulation study proposes a broadband, tunable, and angle-insensitive terahertz perfect absorber based on a monolayer MoS2 asymmetric “C” – shaped metasurface. The absorber employs a simplified three-layer architecture: patterned MoS2 layer/SiO2 dielectric layer/Au reflective layer. Finite-difference time-domain simulations demonstrate that the absorber achieves over 91.4% absorption within 0.83-1.43 THz (relative bandwidth of 53.1%), with near-perfect absorption (>99%) across 0.9-1.36 THz, peaking at 99.7% at 1.24 THz. Dynamic modulation is realized by adjusting carrier concentration (0.8 ×1014 − 1 ×1015cm - 2) through bias voltage (5-10 V). The structure maintains stable performance (fluctuation <4.1%) within a 60° incidence angle range. Electric field and surface current analyses reveal that the broadband absorption originates from the synergistic coupling of magnetic and electric dipole resonances enabled by the asymmetric geometry. This work demonstrates that high-performance terahertz absorption can be achieved through a structurally minimalist design, providing a practical pathway for tunable, easily fabricated terahertz devices.