محمدرضا جعفری - Department of Condensed Matter, Faculty of Physics, Alzahra University, Tehran, Iran
اکبر اسدی - Department of Physics, Faculty of Science, Imam Khomeini Naval Academy, Nowshahr, Iran

A graphene-based-hybrid plasmonic waveguide (GHPW) with a unique geometric structure is designed for surface plasmon polariton guidance and modulation at the frequency area of ۱۰ to ۳۰ THz. The GHPW consists of a graphene layer in the middle, a high-density polyethylene (HDPE) gating layer, two interior dielectric delimiter layers, and two exteriors semi-cylinder Germanium substrates symmetrically embedded on both edges of the graphene. Because of the matchless semi-cylinder structure design, the electromagnetic wave interaction with graphene ultimate subwavelength SPPs strong confinement with long propagation length. Small normalized mode area of ~۱۰-۴ and long propagation length of ۱۰.۶۷-۲۸.۹۲ μm at Fermi energy of ۱.۰ eV is attained for SPPs modes propagation of the GHPW in the frequency bound of ۱۰-۳۰ THz and semi-cylinder radius R > ۴۵۰ nm, respectively. By controlling the graphene Fermi energy, it is found that the structure has a modulation depth higher than ۲۰ % for the frequency band of ۱۰-۳۰ THz and arrives at the peak of approximately ۱۰۰ % at a frequency greater than ۲۸.۷۵ THz. To benefit from the great broadband MIRpropagation and modulation efficiency, the GHPW may promise different MIR waveguides, modulators, photonic, and optoelectronic devices.

Graphene, Plasmonic, Waveguide, Modulator, mid-infrared, Finite element method