Gaussian pulse ($I(t)=I_0{e}^{-t^2/(2{\sigma }_t^2)}$)

A Gaussian pulse has a field or intensity envelope specified by a Gaussian function; the distinction must be stated. For the displayed intensity, the temporal full width at half maximum is $2\sqrt{2\ln 2}{\sigma }_t$. A transform-limited pulse with this shape has intensity spectral and temporal widths satisfying $\Delta \nu \Delta t=2\ln 2/\pi$. A quadratic spectral phase can lengthen the pulse without changing its spectral intensity.