Laplacian pulse width, rms chirp, and their applications

Two new parameters, called Laplacian pulse width and root-mean-square (rms) chirp, are defined for ultrashort optical pulses. Using these parameters, we derive a simple new criterion to determine when a pulse, of arbitrary profile, is transform limited. The Laplacian pulse width and the rms chirp are measured for the first time. The new parameters are shown to be useful in the analysis of ultrashort-pulse propagation in ultrafast and soliton systems. The Laplacian spectral width is also defined and used, in conjunction with the rms spectral derivative of phase, in the calculation of the rms pulse width.