Demonstration of Thermally Tunable Multi-Band and Ultra-Broadband Metamaterial Absorbers Maintaining High Efficiency during Tuning Process

Abstract

Metamaterial absorbers (MMAs) with dynamic tuning features have attracted great attention recently, but most realizations to date have suffered from a decay in absorptivity as the working frequency shifts. Here, thermally tunable multi-band and ultra-broadband MMAs based on vanadium dioxide (VO2) are proposed, with nearly no reduction in absorption during the tuning process. Simulations demonstrated that the proposed design can be switched between two independently designable multi-band frequency ranges, with the absorptivity being maintained above 99.8%. Moreover, via designing multiple adjacent absorption spectra, an ultra-broadband switchable MMA that maintains high absorptivity during the tuning process is also demonstrated. Raising the ambient temperature from 298 K to 358 K, the broadband absorptive range shifts from 1.194–2.325 THz to 0.398–1.356 THz, while the absorptivity remains above 90%. This method has potential for THz communication, smart filtering, detecting, imaging, and so forth.

Broadband plasmon-induced transparency to an anapole mode induced absorption conversion Janus metastructure by a waveguide structure in the terahertz region

“…After a meticulous review of the recently published relevant studies, which demonstrate tunable characteristics, [54][55][56][57] it has come to our attention that the prime merit of the structure we devised lies in its ability to manifest remarkable Janus properties. Notably, compared to the proposal designed by Mou et al, 58 our MS exhibits an unparalleled wideband absorption capacity ranging across 0.7 to 10 THz when confronted with backward incident EM waves, showing excellent incident angle stability. This prominent feature sets our design apart from other existing alternatives.…”

A multifunctional switching bidirectional optical absorber based on a titanium nitride metamaterial

“…However, the current MIM structure F–P absorber can only obtain ideal light absorption on one side of the structure, which seriously restricts its application in multi-functional optical integration and practical optoelectronic devices. 15–21 Although the preparation method of this new type of switchable absorber has been preliminarily explored, the preparation process is complicated and the potential physical mechanism is still unclear. 22–24…”

“…However, the current MIM structure F-P absorber can only obtain ideal light absorption on one side of the structure, which seriously restricts its application in multifunctional optical integration and practical optoelectronic devices. [15][16][17][18][19][20][21] Although the preparation method of this new type of switchable absorber has been preliminarily explored, the preparation process is complicated and the potential physical mechanism is still unclear. [22][23][24] In this paper, based on a high temperature resistant material TiN and MIM structure, a multi-functional tunable optical switching device is proposed, which combines ultra-wideband absorption and narrowband absorption in the visible to nearinfrared band.…”