MUTUAL INTERFERENCE AND STRUCTURAL-PROPER TIES OF IMAGES OF THE SOURCE IN VICINITY OF THE GRAVITATIONAL LENS CASP POINT - THE DEGREE OF MUTUAL COHERENCE OF IMAGES

The interferometric properties of images of the gravitationally lensed source located near the casp point of the gravitational lens are inve stigated. The degree of mutual coherence is calculated analytically fo r all the pairs of images. The mutual coherence in gravitational micro lensing is shown to reach a few tens percents within the radio waveban d for the source dimensions of order of the quasar core and within the optical waveband for the source dimensions comparable with sizes of t he broad emission line clouds of quasars.