LAUSR

In this paper, an assembly of substrate mediated graphene-coated cylindrical nano-rods is proposed as an efficient broadband absorber. Initially, a square lattice of isolated graphene-based particles is considered and a single-band perfect optical absorber is obtained. Then, the possibility of absorption spectrum modulation using the lattice periodicity is illustrated. Moreover, it is exhibited that the performance is stable concerning any polarization state and incident angle up to around 60°. The absorption mechanism relies on the excitation of localized surface plasmon resonances (LSPRs) of various orders on the different sections of the unit cell. Later, the particles are connected through optimized bridges to enhance the operating bandwidth. The bridges also offer the opportunity for the real-time tunability of the absorption spectrum by the electrostatic scheme. The attained absorption band regarding the efficiency of 90% is extended to a 15.43 THz span (18.57–34 THz) using a geometrically simple structure.