All-dielectric double-layer honeycomb tunable metamaterial absorber with integrated gold nanoparticles

The optical regulation strategy of gold nanoparticles can significantly improve the performance of terahertz devices. We designed an all-dielectric double-layer honeycomb metamaterial absorber (MA) to demonstrate the broadband terahertz absorption characteristics in the presence or absence of gold nanoparticles. When it does not contain gold nanoparticles, MA exhibits a peak absorption efficiency of over 99% within the bandwidth range of ∼486 GHz . In particular, gold nanospheres (AuNPs), gold nanobipyramids (AuNBPs), and gold nanorods (AuNRs) are used to modulate the optical coupling effect of metamaterial absorbers, which improves their modulation performance. In the simulation, the effective medium theory (EMT) was applied to quantitatively calculate the optical response of a metamaterial absorber with an integrated gold nanoparticle equivalent gold layer. The integrated gold nanoparticle equivalent gold layer can achieve modulation enhancement of one order of magnitude. In the experiment, our process is compatible with CMOS technology, which may contribute to the development of terahertz detectors. In addition, the tunability and modulation enhancement characteristics demonstrated are beneficial for creating dynamic functional terahertz devices, such as THz modulators and switches.