Conclusions

In this book we have mainly reviewed canonical quantum descriptions of light propagation in a nonlinear dispersionless dielectric medium and in linear and nonlinear dispersive dielectric media. These descriptions have regularly been simplified by a transition to one-dimensional propagation, which has been illustrated also by some original simple descriptions. Besides this we have reported criticisms of description of light propagation in a nonlinear medium using a spatial variable instead of and similarly as the quantum-mechanical time parameter.