Reflection of a Gaussian laser pulse by an active medium

The reflected laser pulse is both temporally and spatially displaced due to spatial and chromatic dispersions when a Gaussian laser pulse is incident onto an active medium. In the case of no chromatic dispersion, the temporal shift is linearly related to the spatial Goos–Hänchen shift. Furthermore, for an incident TE-mode laser pulse, the transmitted laser pulse shifts spatially and temporally by exactly a half of that of the reflected laser pulse. We further point out that, compared to the Goos–Hänchen shift at the critical angle which was conventionally considered the maximum, the Goos–Hänchen shift for the grazing incidence is bigger by one order of magnitude. This can greatly ease the direct experimental study of the Goos–Hänchen shift.