The interaction of graphene with THz electromagnetic waves is dominated by
the collective, thermodynamic response of conduction electrons in graphene to
the THz excitation. Due to very efficiently energy transfer from the incident
electromagnetic field to electronic system of graphene, facilitated by the
excellent transport properties of Dirac electrons, the electronic temperature
in graphene becomes strongly modulated by the THz excitation. As a result, the
THz conductivity of graphene becomes highly nonlinear, leading to very strong
THz saturable absorption and extremely efficient THz high harmonics generation
in graphene. The effective nonlinear coefficients of graphene in the THz
frequency range exceed that of any known material by many orders of magnitude.
This possibly makes graphene the most nonlinear material we know.
Kollektorn, lecture room, Kemivägen 9, MC2-huset