Multiband Ultrathin Polarization-Insensitive Terahertz Perfect Absorbers With Complementary Metamaterial and Resonator Based on High-Order Electric and Magnetic Resonances

Abstract

Terahertz perfect metamaterial absorbers (PMA) based on higher order resonances have exhibited important applications in detecting, sensing, and imaging. However, most of them suffer from polarization and incident-angle dependence due to their asymmetrical structure. Here, we numerically investigate a kind of ultrathin triple-band PMA with polarization stability and wide angle of incidence. Numerical results reveal that three resonance peaks with nearly 100% absorptivity are obtained at 1.605, 4.425, and 4.946 THz under different polarization angles. It is interestingly found that the absorptance of two higher order resonances is inversely increased when the size of the middle dielectric spacer is smaller. The three resonance peaks in transverse electric and transverse magnetic modes nearly maintain fixed for oblique incidence up to 60°. Importantly, another four-band and dual-band perfect absorptions are easily achieved by a complementary method without doing iterative numerical simulation. The complementary metamaterial based absorber reaches more than 98% absorptance at four resonance frequencies. The metamaterial absorber based on complementary resonator also obtains two absorption peaks at 2.65 and 5.84 THz.

Design and Fabrication of a Triple-Band Terahertz Metamaterial Absorber

“…Compared with other absorbers, our structure has the advantage of being polarization insensitive, easy to fabricate, and having a thin dimension and a simple construction. In order to evaluate the performance of our absorbers, we compared the results with other structures [31,[35][36][37][38], as depicted in Table 1. From the table, we can see that of the three peaks, the absorption rate of the first and third peak is more than 98%.…”

A Broadband Polarized Metamaterial Absorber Driven by Strong Insensitivity and Proximity Effects

“…High electromagnetic loss can be accomplished through a large resonant imaginary part of the refractive index. In such a way, at most electromagnetic energy absorption is possible to accomplish by minimizing the transmittivity, and reflectivity [40]- [42]. The maximize absorption electromagnetic incident energy is then converted into heat.…”

A Terahertz Metamaterial Absorber-Based Temperature Sensor Having Nine Resonance Peaks

“…In this method, the number of rings basically determines the number of absorption bands [9,13,14]. Alternative metallic or complementary inclusions are also added to well-known resonator structures to simply increase the frequencies of operation [15][16].…”