ABSTRACT
In the previous chapter, we have discussed the effect of a second-order nonlinearity on wave propagation, with emphasis on second-harmonic generation using plane waves, and later, beams. In this chapter, we investigate in more detail the effect(s) of optical nonlinearities on beam propagation. In particular, we will first investigate the effect of a cubic nonlinearity because this gives rise to self-phase modulation (SPM), which can modify the beam profile during its travel. Later we will also show in more depth how the presence of only a quadratic nonlinearity along with phase mismatch can simulate the effect of a cubic nonlinearity.
