Propagation dynamics of a circular Airy beam in a uniaxial crystal

This paper investigates theoretically and numerically the propagation characteristics of a circular Airy beam (CAB) in a uniaxial crystal in detail. The beam loses its boundary cylindrical symmetry during propagation because of the medium anisotropy, although it propagates along the optical axis. This effect of anisotropy on the propagating beam becomes increasingly evident with the increase of the propagation distance. Another main influential factor of the propagation characteristics is the ratio of the extraordinary refractive index to the ordinary refractive index (n_e/n_o). The more the value deviates from 1, the worse the symmetry of the beam intensity distribution becomes. The polarization becomes notably complicated, but possesses a vortex state with a topological charge of 2 during propagation. The abruptly autofocusing characteristic, the most important property of CABs, also appears when the crystal length is long enough, which is greatly different from that characteristic in isotropic media. This work is helpful for the design of optical devices based on uniaxial crystals for beams with some special wavefronts.