Effects due to laser pulse duration

consider excitation by a pulse A(t) of laser radiation (fig. 9.11(b)). If the laser pulse is long on a timescale set by the magnitude of the avoided 

It is also known that the atoms may be left in highly excited states 

The model outlined here is taken further in chapter 10, which deals with the order-to-chaos transition in atoms, and a classification of the different kinds of transition which can occur for excitation near avoided crossings will be given. 

In the present chapter, the rapidly growing subject of atoms in strong laser fields has been briefly described, the main emphasis being on the novel effects which have been observed. Several aspects of the problem have not been discussed for example, above 1020 Wcm-2, relativistic effects will become important, although these have not yet been observed. Similarly, we have omitted any discussion of coherent control in two-colour excitation and femtosecond chemistry. 

---