  We study electromagnetic properties of a double layer graphene system in
which electrons from one layer are coupled with holes from the other layer. The
gauge invariant linear response functions are obtained. The frequency
dependences of the transmission, reflection and absorption coefficients are
computed. We predict a peak in the reflection and absorption at the frequency
equals to the gap in the quasiparticle spectrum. It is shown that the
electron-hole pairing results in an essential modification of the spectrum of
surface TM plasmons. We find that the optical TM mode splits into a low
frequency undamped branch and a high frequency damped branch. At zero
temperature the lower branch disappears. It is established that the pairing
does not influence the acoustic TM mode. It is also shown that the pairing
opens the frequency window in the subgap range for the surface TE wave.

Mesoscale and Nanoscale Physics