On the diffraction of ultrashort pulses

The diffraction of ultrashort pulses of electromagnetic radiation is considered in terms of the model of an initial Gaussian time pulse and a Gaussian beam. A criterion for the short pulse duration and the average pulse wavelength are introduced, and the diffraction length and angular divergence of radiation are estimated. Along with the general expression for a field, simple expressions for the case of the far zone are derived. The results obtained are compared with the simplified delta pulse model.