Spatial-time pattern of electrical field of terahertz pulse in the far field

The spatial and temporal dependence of the electric field amplitude of a terahertz (THz) pulse of several oscillations in the far field near the focal plane of a parabolic mirror was experimentally obtained. During experimentation a spacetime anomaly was discovered in the diffraction patterns. In the wave front of the field the amplitude decreases to zero, and going through this spatial plane, the phase of oscillations changes, while in the integrated intensity, there is a dip in the curve. The results can be applied in pulsed terahertz optics and spectroscopy.