The multiple-spike structure of ruby laser output at and over the pumping threshold is observed. Photographs of the far-field patterns

near-field patterns and intensity distribution of the end face are given. Effects of variation of pumping energy and angular position of the ruby rods on the patterns are studied. It has been found that the far-field pattern of the higher quality crystals has a characteristic direction

which rotates with the rotation of the crystal. At a certain angle of rotation

the centre of the far-field pattern has a mosaic-type structure and fine interference fringes

and the transverse mode structure on the near-field patterns appears. Two-pinhole interference fringes of the near-field patterns are obtained. It is shown that the above phenomenon depends strongly on the quality of the ruby rods （including the crystallization

fabrication and coating）. The experimental results are discussed qualitatively in the light of the optical dielectric waveguides and coherent scattering mechanism.