Broadband terahertz characterization of graphene oxide films fabricated on flexible substrates

Graphene oxide (GO)fabricated on various flexible substrates (Kapton and lamination sheets) are studied with the help of terahertz time domain spectroscopy (THz-TDS) technique. In this work, GO films are grown using laser scribing technology, popularly names as Laser Induced Graphene (LIG) also, in the ambient conditions making the process cost-effective as well as user friendly. Terahertz transmission study, along with the sample images, suggests the presence of optical anisotropy in the fabricated GO films for different directions of laser scribing. It is further observed that THz transmissions are dominated by the Fabry Perot oscillations along with the wave guide resonance mode within the broadband THz characterization window. Several frequency dependent parameters (refractive index, conductivities, optical densities) essential for designing flexible terahertz devices are experimentally extracted for 0.3 THz to 2.0 THz frequency range. In near future, the outcome of this work can be helpful in integrating GO with flexible terahertz technology.