Spectral characteristic of single layer graphene via terahertz time domain spectroscopy

Distinctive optical properties of graphene with the unique electronic structure in terahertz time domain spectrum could be widely applied in phononics and photonics. We show that time domain signal main-peak of single-layer graphene has hardly any delay relative to the reference signal formed by dipole approximation. Frequency spectrum appeared some absorption peaks and band-width decreased to 2.8 THz with oscillatory structure due to the mismatch strain and the interfacial interaction between graphene and substrate. We described dispersion relation and light absorption of graphene in terahertz range, light absorption coefficient of single layer graphene less than 3% at low photon energies.