Graphene terahertz metamaterials absorber with multiple absorption peaks and adjustable incident polarization angle

Abstract

In this work, we propose a novel graphene terahertz metamaterials absorber with multiple absorption peaks and incident polarization angle. The absorber achieves five distinct absorption bands within the 9–14 THz frequency range, with an average absorption rate of 96.4 %. By tuning the bias voltage, the Fermi level of graphene can be dynamically adjusted, allowing flexible control over the absorption frequencies. Moreover, the device maintains strong absorption performance for incident angles up to 60°, making it suitable for a wide range of oblique incidences. Due to the absence of 90° rotational symmetry in the structural design, the absorber exhibits notable variations in absorption efficiency at certain frequencies when the polarization angle of the incident wave is altered. This unique polarization-dependent behavior holds potential for applications in photonic and optoelectronic devices that require polarization-selective responses to electromagnetic waves. In addition, the highest sensitivity(S) and figure of merit (FOM) of the absorber reached 10670nm/RIU and 32.7/RIU, respectively, showcasing the absorber's superior sensitivity and efficient tunability. The absorber's ability to achieve multi-frequency absorption with excellent characteristics also paves the way for designing next-generation, adjustable terahertz devices, contributing valuable insights for future research and development in this field.