The role of dispersion in ultrafast optics

In this article, we review the phenomenon of dispersion, paying particular attention to its impact in the optics of ultrashort pulses, as well as its measurement and management. At present, lasers generating coherent bandwidths of several hundred nanometers have been demonstrated and correspondingly short pulses of 10 fs or so are quite usual. The limits to the breadth of optical spectra and brevity of pulse durations that may be achieved are often set by the dispersive properties of the linear optical elements of which the source is constructed. Progress in ultrafast optics to date has therefore relied extensively on the development of ways to characterize and manipulate dispersion. The means by which this can be accomplished are significantly different for laser oscillators and laser amplifiers, as well as for nonlinear interactions that are used to extend the range of frequencies at which short optical pulses are available, but in all cases it is this phenomenon that determines the output of current optical sources.