Polarization-sensitive terahertz spectroscopy of graphene nanostructures

Abstract

Abstract Efficient devices for control temporal and spatial properties of electromagnetic waves are essential for the development of terahertz (THz) technologies. But despite the great progress achieved in a study of graphene, the influence of the number of graphene layers on its optical and electrical properties in the THz frequency range has not yet been sufficiently studied. In this work, we experimentally studied optical and electrical properties of multilayer graphene (MLG) thin films in the frequency range 0.2–0.8 THz (corresponding to a wavelength range ∼1.5–0.37 mm), at a controlled room temperature of 291 K, and a relative humidity of 40 %. Using our custom-made THz time-domain spectroscopic polarimetry system, we obtained spectra of the complex relative permittivity and the electrical conductance of the chemical vapor deposition graphene with ∼14, ∼40, and ∼76 layers of graphene on borosilicate glass substrates. It is shown that the conductance increases nonlinearly with an increase in the graphene layer number and reaches, for ∼76 layers, 0.06 S for the real, and 0.03 S for the imaginary part, respectively. Our results show that by using MLG it is possible to create tunable devices that can be used in the advanced areas of THz photonics.