Recent developments in the measurement of ultrashort laser pulses using frequency-resolved optical gating

Frequency-Resolved Optical Gating (FROG) is a technique for measuring the intensity, I(t), and phase, /spl phi/(t), of arbitrary ultrashort pulses. FROG operates a multi- or single-shot basis and has measured pulses from the UV to the mid-IR, from many /spl mu/J to a few pJ, and from several ps to 9 fs. It has many applications and, for example, is now being used to perform spectroscopic measurements. Recent developments include the use of an artificial neural network for rapid pulse retrieval and the use of spectral interferometry in conjunction with FROG to achieve the rigorous measurement of pulses containing less than a single photon (on a multishot basis).