Depth of Field of Finite Energy Airy Shaped Waves

In the present paper the analytical aspects related to the maximum invariance depth of propagation finite energy Airy-type beams are investigated, considering not only the usual exponentially dumped Airy beams but also the truncated ones. It is obtained an analytic expression which seems capable of finding accurately the maximum invariance distance of these waves. The results seem to be in line with those obtained from numerical simulations.