Media behave in a nonlinear fashion when the light intensities are high and this leads to the generation of new frequencies through second harmonic generation and parametric processes. Nonlinear effects such as self phase modulation etc. have also become very important in the field of optical fibre communications. The course will address the basic physics and applications of such nonlinear phenomena.

Although most optical effects can be explained using classical Maxwell's equations, there are many phenomena, which need the complete quantum mechanical description of light which will be discussed in the course. Quantum nature of light is playing a very important role in the field of quantum information science with applications in quantum cryptography, quantum computing etc. and the basics learned in the course should be of interest to students wishing to pursue the field of quantum information. (from nptel.ac.in)