No abstract

A MoS2 and graphene stacked structure is proposed as metamaterials for a triple-band terahertz absorber in this work. The complementary frequency-selective surface of the absorber, consisting of two crossed linear slots and four pairs of concentric circular slots, has three absorptions at 0.6 THz (99.7%), 1.5 THz (95.4%), and 2.5 THz (99.5%). The polarization of the THz absorber is less sensitive to the incident angle within a certain range. By controlling the material properties of MoS2 and graphene, the peak absorption frequency can be tuned within a certain range. The stacked structure of different 2D materials provides new ideas for the design of the THz absorber, which is important for THz in detection, communication, and imaging applications.

The MoS2 surface plasmon resonance structure is proposed as a THz absorber in this work. The absorber adopts a double layer structure of Archimedean spirals stacked with split rings. In 1.2–3.0 THz, the absorption is greater than 92%, and the relative absorption bandwidth reached the value of 85.7%. Due to the circular-like symmetry of the unit, the polarization of the absorber is less sensitive to the incident angle within a certain range. When the incident angle is within 60°, the absorption in the bandwidth is still greater than 85%. The design efficiency is also significantly improved by the combined method of the equivalent circuit and finite difference time domain. Our work provides new directions for the design of terahertz devices, which is of great importance for various fields including terahertz imaging, detection and sensing, and especially in 6G communication systems.

This paper presents an electrically controllable reflective broadband linear polarization (LP) converter based on liquid crystals (LCs) for cross-polarization conversion (CPC) in the terahertz frequency range. The proposed structure achieves a high polarization conversion ratio (PCR) exceeding 0.9 within the frequency range of 236.8 - 269.6 GHz. A vital feature of this design is the dynamic control of polarization conversion by re-orienting the nematic liquid crystal molecules through voltage bias switching between ‘on’ and ‘off’ states, allowing for precise manipulation of cross-polarized and co-polarized reflected waves. Experimental results validate the simulation outcomes, demonstrating excellent agreement. In contrast to conventional reflective polarization converters with fixed frequency responses, the proposed electrically controllable polarization conversion offers significant potential in imaging and optical communications.

No abstract