Propagation of surface magnetoplasmon polaritons in a symmetric waveguide with two-dimensional electron gas

The properties of surface magnetoplasmon polaritons (SMPPs) in a symmetric structure, composed of two semi-infinite regions of high-density two-dimensional electron gas (2DEG) separated by a thin film in Voigt configuration, are investigated. The normal and absorption dispersion relations for the transverse magnetic polarization are derived by correlating Maxwell's equation and the boundary conditions. It is demonstrated that the features of SMPPs are greatly influenced by the external magnetic field, collision frequency of 2DEG, the dielectric constant, and the thickness of the thin film, suggesting that the locations and propagation lengths of SMPPs can be governed accordingly. It is shown that the symmetry of the physical geometry preserves the symmetry of the dispersion relations of SMPPs. Furthermore, it is discovered that as the external magnetic field increases, the penetration depth of SMPPs decreases, while their energy loss reduces, implying that plasmons can propagate for longer distances. Additionally, it is observed that SMPPs in the symmetric configuration have a longer lifetime than those in the asymmetric configuration.