Plasmonic mode coupling in graphene-based photonic crystals

摘要

Plasmonic bands in 1D graphene-based photonic crystals have recently been reported for transverse magnetic polarization in the low THz regime. In this work, we demonstrate that plasmon coupling, giving rise to plasmonic bands, is also present for transverse electric polarization at IR frequencies corresponding to the region of interband transitions in graphene. Due to the doping level dependence of graphene interband optical conductivity, plasmonic band region can be shifted in the IR frequency regime for different doping levels. We have analyzed graphene-based photonic crystals with a homogeneous and periodic doping level sequence along crystal growth direction in the unit cell; our results prove that plasmonic band opening is obtained for these two different graphene doping sequences, in the frequency region such that imaginary optical conductivity turns negative, displaying different levels of attenuation due interband absorption processes. Finally, we show that TE plasmonic modes in a finite multilayer can be excited by attenuated total reflection technique in Otto configuration.