Novel dynamic tuning of broadband visible metamaterial perfect absorber using graphene

We present a novel dynamic tuning of a broadband visible metamaterial absorber consisting of a multilayer-graphene-embedded nano-cross elliptical hole (MGENCEH) structure. It has multiple effects, including excitation of surface plasmon polaritons and extraordinary optical transmission in the first two metal layers. A numerical simulation shows that the MGENCEH structure can realize broadband perfect absorption (BPA) from 5.85 × 10¹⁴ to 6.5 × 10¹⁴Hz over a wide incident angle range for transverse magnetic polarized light if the chemical potential of graphene (u_c) is tuned to 1.0 eV. Furthermore, it has high broadband absorption (above 96%) from 4.6 × 10¹⁴ to 6.6 × 10¹⁴Hz and three areas of narrowband perfect absorption around 4.65 × 10¹⁴, 5.1 × 10¹⁴, and 5.6 × 10¹⁴Hz. The changes in the absorption spectra as a function of u_c can be classically explained by simply considering plasmons as damped harmonic oscillators. This BPA is broader than the result of Zhou et al. [Opt. Express 23, A413-A418 (2015)] and is particularly desirable for various potential applications such as solar energy absorbers.