EXPERIMENTAL-VERIFICATION OF NONDIFFRACTING X WAVES

The authors have embedded descriptions for localized nondiffracting waves such as Durnin's wave in a generalized family of exact solutions to the isotropic/homogeneous wave equation. The first experimental production of acoustic forms of a subset of these solutions that the authors term. "X waves" are reported. Our generalized expression includes a term for the frequency response of the system and parameters for varying depth of field versus beam width of the resulting family of beams. Excellent agreement between theoretical predictions and experiment was obtained. An X wave of finite aperture driven with realizable (causal, finite energy) pulses travels with a large depth of field (nondiffracting length).