  We present a family of localized radiation modes in multilayered periodic
media, where in-phase superposition of p-polarized waves leads to radiative
confinement around the beam axis. Excitation of surface plasmon polaritons
yields an enhanced localization normally to the interfaces. On the other hand,
the spectral filtering induced by the presence of bandgaps allows to achieve
transverse superresolution on the interfaces. Subwavelength beamwidths along an
infinitely long distance might potentially be obtained.
