Bessel pulse beams and focus wave modes

Free-space propagation of ultrashort pulses is investigated. Space-time cou plings are reduced for a particular form of beams that is termed a pulse be am, or a type 3 pulsed beam. General conditions for the formation of pulse beams in the paraxial approximation are presented. The free-space propagati on of spatially localized ultrashort laser pulses is investigated. This tre atment is based on a particular pulsed form of the well-known Bessel beam, which is termed a Bessel pulse beam. The connections with focus wave modes and X waves are discussed. (C) 2001 Optical Society of America.