Beyond the spatio-temporal model in femtosecond optics

We use the method of amplitude envelopes to obtain a class of linear nonparaxial amplitude equations, governing the propagation of short optical pulses in media with dispersion, dispersionless media and vacuum. The equations are solved using the method of Fourier transforms and fundamental and exact analytical solutions are obtained. Nonparaxiality leads to nonsymmetrical diffraction enlargement of light pulses and to their transformation in light disks on several diffraction lengths.