ABSTRACT
In this chapter we describe how pulses of light at almost any frequency from x-rays to terahertz (THz) can be applied to problems in chemistry, biochemistry and physics. As predicted a decade ago [1], the production of femtosecond pulses has led to many new and fascinating observations. Indeed, the number of applications of ultrafast lasers has mushroomed; an electronic search of Chemical Abstracts for the terms ‘femtosecond’ and ‘ultrafast’ yields 19 000 references and obviously it would be impossible to describe all of these in the limited space available here, even if it were possible to become familiar with them all! Moreover, the first attosecond pulses are now being made [2-7] and there is even a proposition for the generation of zeptosecond pulses [8]. As such, the future of time-resolved spectroscopy appears to be brighter than ever.
