Three dimensional imaging of short pulses

We exploit a slightly non-collinear second-harmonic cross-correlation scheme to map the 3D space–time intensity distribution of an unknown complex-shaped ultrashort optical pulse, down to a resolution of 10 μm in space and 200 fs in time. Moreover, we directly show that the spatial phase information is not lost in the process, thanks to the coherence of the non-linear interaction. This implies that the concept of second-harmonic holography can be employed down to the sub-picosecond time scale, and used to discuss the features of the technique in terms of the reconstructed fields.