Comparison of Graphene-Based Transverse Magnetic and Electric Surface Plasmon Modes

Dispersion properties and field distributions of graphene supported transverse magnetic (TM) and transverse electric (TE) surface plasmon (SP) modes in air-graphene-SiO₂-Si structures have been investigated. The results show that graphene-based TM (TE) SPs are bound (lossy) modes, which decay into the air in the range of tens of micrometers (several thousand micrometers). In addition, when the thickness of the SiO₂ layer is in the range of 200-300 nm, the influence of the Si substrate on the dispersion property is significant (negligible) for the TM (TE) modes. Furthermore, the effective indexes of the graphene TM (TE) modes increase with the increase (decrease) of the frequency. Compared with the traditional metal-based structures, graphene-based TM mode exhibits a better confinement but with a larger loss. The presented results are useful for the design of compact graphene-based optoelectronic devices.