High order harmonic generation in graphene

Single layer graphene (SLG) has remarkable physical properties, with potential interest in the fields of electronics and photonics. While being single-atom thick, SLG presents a rather strong optical response, as a large optical absorption, resonance for all excitation frequencies up to the vacuum UV and, therefore, a strong broadband linear response, etc. It has been also pointed out that the non-linear response to THz radiation [1] is also particularly strong, and nonlinear susceptibilities are found orders of magnitude above that of transparent materials, and of the same order as of other resonant materials, as metal nanoparticles. The interaction of graphene with intense short pulse lasers in the optical domain remains, however, a subject for detailed investigations [2].