  The modulation of the optical transmittance in multilayer graphene by means
of an electrical signal in the simple configuration of coplanar electrodes is
reported. Besides the fundamental frequency of modulation, higher harmonics
also appear in the transmitted signal. Modulation is also observed in the
optical reflectance. The modulation of the optical properties in multilayer
graphene by electrical signals may be useful for the transmission of
information by optical means.
