THz wave scattering by a graphene strip and a disk in the free space: integral equation analysis and surface plasmon resonances

Abstract

The excitation of the surface plasmon resonances on a graphene strip and a disk in free space is studied numerically as a 2D and 3D electromagnetic wave-scattering problem, respectively. The associated mathematical model is based on the Maxwell equations with resistive boundary conditions on the surface of a zero-thickness strip or disk, where the graphene electron conductivity is included as a parameter and determined from the Kubo formalism. It is shown that plasmon resonance frequencies in the terahertz range shift with variation of the chemical potential of the graphene. Far-field and near-field patterns are plotted at several resonance frequencies.

Scattering and absorption performance of a microsize graphene-based parabolic reflector in the THz range illuminated by a complex line source

“…The forward directivity is getting higher with the higher chemical potential values. As mentioned above, if the frequency is getting higher then a graphene reflector becomes more and more transparent because its surface impedance Z increases almost linearly, with the dominant imaginary part, and finally it exceeds the free-space impedance value (see [3,[14][15][16]). Therefore, the linear increase in the forward directivity is restricted to lower THz range and is replaced with reduction if the frequency gets above 2 THz for realistic values of the chemical potential.…”

“…The role of the SP resonances is also a matter of study. Here, we can keep in mind the scattering and absorption of THz waves by flat graphene strips and finite graphene-strip gratings has already shown the presence of SP resonances, especially strong in the lower part of THz range [14][15][16][17][18][19].…”

Focusing of THz waves with a microsize parabolic reflector made of graphene in the free space

“…Note that the scattering and absorption of THz waves by a single flat graphene strip and finite graphene-strip gratings was reduced to SIE and its Nystrom type solution was built in [13,14]. Infinite graphene-strip grating in the free space was also studied by the MAR-RHP technique in [10].…”

Marching-on-in-Degree Time-Domain Integral Equation Solver for Transient Electromagnetic Analysis of Graphene

“…The transfer matrix method (TMM) [2] and rigorous coupled wave analysis (RCWA) [4] are very efficient for some particular graphene structures. As for more general full-wave numerical simulation, various methods are available, including but not limited to the finite integration technique (FIT) [5], the finite element method (FEM) [6], the method of moments (MOM) [7,8], and the Nyström method [9,10]. For transient electromagnetic analysis, time domain techniques are preferred, e.g., the finite-difference time-domain (FDTD) [11][12][13], discontinuous Galerkin time domain (DGTD) method [14][15][16], and the time-domain integral equation (TDIE) method [17,18].…”