The evolution properties and the spectral degree of coherence of a partially coherent multi-Gaussian Schell-model vortex (MGSMv) beam propagating in uniaxial crystals orthogonal to the optical axis are studied. Propagation expression for the cross-spectral density and the average intensity of the partially coherent MGSMv beam propagating in uniaxial crystals are derived. Some analyses are illustrated by numerical examples related to the propagation properties and coherence vortices of the partially coherent MGSMv beam in uniaxial crystals. Numerical results show that, upon propagating in uniaxial crystals, the partially coherent MGSMv beam loses its initial dark center distribution. After propagating for sufficient distances, the partially coherent MGSMv beam will also evolve into a flat-topped beam. The evolution behavior of average intensity and coherent vortices depends on the crystal including the ratio of extraordinary and ordinary refractive indices, and beam parameters including the spatial correlation length and topological charge of the beams, as well as the propagation distance.
Since 2001, we have started to do some works on how to approach to virtual observatory in Yunnan Observatory. We have finished a prototype distributed controller of CCD camera, we have established a search engine for 2MASS database, and we have finished a prototype system of data archiving, browsing, searching for H-alpha image data of the sun, etc. Based on these efforts, we are trying to use up-to-date IT technologies to unite all these efforts, and integrate both astronomical database and astronomical instruments into a Virtual Observatory.