  We study the optical properties of double-layer graphene for linearly
polarized evanescent modes and discuss the in-phase and out-of-phase plasmon
modes for both, longitudinal and transverse polarization. We find a energy for
which reflection is zero, leading to exponentially amplified transmitted modes
similar to what happens in left-handed materials. For layers with equal
densities $n=10^{12}$cm$^{-2}$, we find a typical layer separation of
$d\approx500\mu$m to detect this amplification for transverse polarization
which may serve as an indirect observation of transverse plasmons. When the two
graphene layers lie on different chemical potentials, the exponential
amplification either follows the in-phase or out-of-phase plasmon mode
depending on the order of the low- and high-density layer. This opens up the
possibility of a tunable near-field amplifier or switch.
