Chapter 13 - Ultrafast and Intense-Field Nonlinear Optics

Abstract

This chapter discusses the recent advances that have led to the generation of laser pulses with durations of the order of 1 attosecond. Ultrashort pulses can be used to probe the properties of matter on extremely short time scales. Within the context of nonlinear optics, ultrashort laser pulses are of interest for two separate reasons. The first reason is that the nature of nonlinear optical interactions is often profoundly modified through the use of ultrashort laser pulses. The second reason is that ultrashort laser pulses tend to possess extremely high-peak intensities, because laser pulse energies tend to be established by the energy-storage capabilities of laser gain media and thus, short laser pulses tend to have much higher peak powers than longer pulses. Plasma also plays an important role in nonlinear optics in two different ways. Firstly, nonlinear optical processes such as multiphoton ionization can create plasma; the optical properties of the material system are, thereby modified even by the linear response of the plasma. Secondly, plasma (no matter how it is generated) can respond in an intrinsically nonlinear manner to an applied optical field.