Specific characteristics of the configurations of optical axes in absorptive crystals

The spherical coordinates of four optical axes in absorptive orthorhombic c rystals have been determined in terms of the components of the tenser of in verse permittivity constant (B) over cap = <(<epsilon>)over cap>(-1). The e volution of the configurations of these four vectors has been studied as a function of the complex tenser B. It was shown that anomalous changes in th e angles formed by the optical axes and the orientations of the planes in w hich these vectors are located occur if the parameters of dielectric anisot ropy of the crystal are comparable with the absorption level, In particular , these dramatic changes can be seen in the description of the optical-axis splitting in absorptive uniaxial crystals caused by "inclusion" into consi deration of feeble orthorhombic anisotropy. In these cases, the slight abso rption anisotropy considerably influences the configurations that cannot be reduced to small corrections. (C) 2001 MAIK "Nauka/Interperiodica".