Wave propagation in weakly nonlinear bi-anisotropic and bi-isotropic media

Wave propagation in uni-anisotropic weakly nonlinear media has been discussed before. Presently the skeletal structure of that theory is generalized to bi-anisotropic and bi-isotropic media. The question is of special interest to wave propagation in chiral and gyrotropic media, which have not been analyzed in this context before. We use a special matrix-dyadic notation which in the present case considerably simplifies the procedure. The results show clearly that for bi-anisotropic and bi-isotropic, as well as for uni-anisotropic and isotropic media, the parameters are amplitude dependent, thus predicting the typical nonlinear effects of harmonic generation, self focusing, etc. Novel specific bi-anisotropic and bi-isotropic results are also indicated.