Cylindrically Polarized Nondiffracting Optical Pulses
  We extend the concept of radially and azimuthally polarized optical beams to the polychromatic domain by introducing cylindrically polarized nondiffracting optical pulses. In particular, we discuss in detail the case of cylindrically polarized X-waves, both in the paraxial and nonparaxial regime. The explicit expressions for the electric and magnetic fields of cylindrically polarized X-waves is also reported. 
Marco Ornigotti, Claudio Conti and Alexander Szameit
physics.optics