Optical axes in various absorbing crystals

Analytical expressions have been derived for the components of the complex permittivity tensor as a function of the number of optical axes existing in an absorbing monoclinic crystal. Some specific features of the orientation of these axes are considered. The ellipticities of natural waves are calculated for these crystals, as well as the ellipticities of transmitted light for right- or left-hand circularly polarized waves normally incident on a crystal. A significant difference of particular cases of absorbing monoclinic crystals from the general case of crystal with four circular axes is demonstrated.