Principles of Nonlinear Optics.

摘要

This report contains a summary of essential principles of nonlinear optics such as optical bistability, phase conjugation, and harmonic generation. The origins of nonlinearity are described, tracing it back to its manifestation as the modification of the linear phase velocity of a propagating wave. An analysis is advanced for harmonic/subharmonic generation in a quadratically nonlinear medium without any dc polarization, both in the presence and absence of dispersion. It is also shown that similar effects may be observed in media with quadratic and cubic nonlinearities. Another interesting nonlinear optical effect is bistability and hysteresis. To illustrate the basic principles, a hybrid acoustooptic bistable device is first considered and compared to the electronic Schmitt trigger to highlight the necessity of nonlinearity and positive feedback in achieving bistable operation. The nonlinear Fabry- Perot cavity is next analyzed using the so-called Maxwell-Block equations as a starting point. The limiting cases of purely absorptive and purely dispersive bistabilities are discussed in some detail. (jhd)