  Absolute negative refraction regions for both polarizations of
electromagnetic wave in two-dimensional photonic crystal have been found
through both the analysis and the exact numerical simulation. Especially,
absolute all-angle negative refraction for both polarizations has also been
demonstrated. Thus, the focusing and image of unpolarized light can be realized
by a microsuperlens consisting of the two-dimensional photonic crystals. The
absorption and compensation for the losses by introducing optical gain in these
systems have also been discussed.
