Terahertz wave reflection impedance matching properties of graphene layers at oblique incidence

With the development of terahertz (THz) anti-radar technology, the demands for new antireflection coating technology and materials based on impedance matching mechanism have increased significantly. Herein, the reflection impedance matching properties of p-polarized THz wave at a randomly stacked multi-layer graphene interface is studied using both experiment and theory at oblique incidence. The experiment is performed on a THz-time domain spectroscopy system with variable reflection angle configuration. The reflected pulses from the quartz/graphene/air interface are observed to change with the incident angle and the layer number of graphene. Remarkable pulse shape reversal and impedance matching governed amplitude suppression with broadband response are achieved. Theoretical analysis based on graphene's THz Drude conductivity and a variable angle THz wave propagation model has been proved to agree well with the experimental results. This work makes it clear that the impedance matching mechanisms for the potential THz antireflection devices based on graphene in oblique incidence situation. (C) 2015 Elsevier Ltd. All rights reserved.