Propagation Characteristics of Chirped Circular Airy Beams

In this paper, we analytically and numerically inves-tigate the propagation dynamics of an initially chirped circular Airy beams (CCABs). The results of our analysis show that positive initial chirps act to promote the remarkable enhancement of the autofocusing effect through reducing the focal length, as compared to the conventional unchirped circular Airy beams. Another striking characteristic is that CCAB exhibits a novel abruptly autodefocusing behavior, where central intensity suddenly decreases at far field after abruptly autofocus if the initial chirp is above a critical value. On the other hand, the negative initial chirps always tend to suppress the autofocusing effect through extending the focal length. In particular, the autofocusing behavior is completely eliminated when the magnitude of initial chirp is above a critical value.