Recently, we demonstrated an all-optical coupling
scheme for plasmons, which takes advantage of the
intrinsic nonlinear optical response of graphene.
Frequency mixing using free-space, visible light
pulses generates surface plasmons in a planar
graphene sample, where the phase matching
condition can define both the wavevector and energy
of surface waves and intraband transitions. Here,
we also show that the plasmon generation process is
strongly intensity-dependent, with resonance features
washed out for absorbed pulse fluences greater than
0.1 J m−2. This implies a subtle interplay between the
nonlinear generation process and sample heating. We
discuss these effects in terms of a non-equilibrium
charge distribution using a two-temperature model.Peer ReviewedPostprint (author's final draft
