EN
The present symmetry theory of optical phenomena makes it possible to determine each of 122 point symmetry groups both for non-dispersive as well as dispersive media. This is achieved by considering the symmetry breaking effect external fields (separately E and H) on the propagation of electromagnetic waves. The corresponding results are collected in Tables I-III. The way of measuring the relevant physical quantities is proposed. The point symmetry of a given sample is obtained by comparing the experimental results with their theoretical counterparts. The results given in Tables I-III can also be viewed as the discussion of the "canonical" solutions (effects) for a given symmetry K.