Evolution properties of a complex coherent square Gaussian-Schell-model beam in a uniaxial crystal orthogonal to the optical axis.

The analytical formulas for spectral density, degree of coherence, and effective beam widths of complex coherent square Gaussian-Schell-model (GSM) beams in a uniaxial crystal orthogonal to the optical axis are derived. Based on these analytical formulas, the evolution properties are investigated by a set of numerical examples. It is demonstrated that the complex coherent square GSM beams spread at different rates in the directions parallel and orthogonal to the optical axis due to the anisotropic crystal, but the self-shift effect of the light field is almost unaffected by the fact that the uniaxial crystal is anisotropic. The effect of anisotropy of the uniaxial crystal on the effective width of the beam in the x direction and that in the y direction is completely opposite. The results provide a way for the modulation of the complex coherent square GSM beams and enrich the propagation theory of uniaxial crystal.