Terahertz Wave all-Dielectric Broadband Tunable Metamaterial Absorber

Tunable metamaterial absorbers play an important role in optoelectronic detection, sensing, imaging, and other fields. We propose an all-dielectric broadband tunable metamaterial perfect absorber (MPA) composed of uniformly distributed cross conical metamaterials. Through structural optimization and impedance matching, the absorber achieves broadband, wide angle, and high absorption characteristics. More than 90% absorption efficiency was achieved between 0.6 and 3.0 THz, and almost perfect absorption characteristics were demonstrated between 1.3 and 3.0 THz. Based on structural diffraction analysis and electromagnetic field distribution characteristics, the physical mechanism of designing structural absorption was deeply explored, revealing the dual physical mechanisms of electromagnetic wave diffraction conversion and resonance absorption. In addition, the principle of using light regulation to change the carrier concentration in doped silicon was applied. The carrier concentration in heavily doped silicon was experimentally changed, and the absorber achieved controllable adjustment between 0.07--1.0 THz, verifying the consistency between theoretical design and experimental testing.