Picosecond spectroscopy: applications in biochemistry. Part I: Techniques.

A number of sources of picosecond optical pulses and the means by which they may be used to investigate fast molecular processes have been described. In addition, it should be pointed out that most of these techniques can be extended to take advantage of other properties of the laser pulses; in particular, the polarization is of use in measuring time-dependent antisotropy. The state of the art is now the generation of 30fs pulses; it seems likely that this is all the time resolution that one is likely to need for investigating biological and other molecular processes as at such short times the uncertainty principle leads to a considerable loss of spectral resolution.