SPACE-FREQUENCY ANALYSIS OF NONDIFFRACTING PULSES

A recently introduced method of producing nondiffracting space-time fi elds from ordinary diffracting solutions is here examined in the space -frequency domain, It is shown that in a 3D space the method leads to localized wavefields whose Fourier components are nondiffracting beams . Hence the nondiffracting pulses are spectral generalizations of the monochromatic conical waves, a property which provides novel insight i nto the physical analysis and the actual preparation of such localized space-time fields. In 2D, the resulting temporally varying wavefields are nonlocalized, The nondiffracting pulses obtained via the space-fr equency synthesis of conical waves are illustrated with the help of br oadband X waves and their temporal derivatives for which explicit expr essions are derived. The relation of these fields to the previously kn own localized solutions is established.