  Exact stationary solutions of the electron-photon Dirac equation are obtained
to describe the strong interaction between massless Dirac fermions in graphene
and circularly polarized photons. It follows from them that this interaction
forms bound electron-photon states which should be considered as a kind of
charged quasiparticles. The energy spectrum of the quasiparticles is of
dielectric type and characterized by an energy gap between the valence and
conductivity bands. Therefore the electron-photon interaction results in
metal-insulator transition in graphene. The stationary energy gap, induced by
photons, and concomitant effects can be observed for graphene exposed to a
laser-generated circularly polarized electromagnetic wave.
