Single-shot femtosecond/picosecond-range autocorrelator using tilted pulse front

We demonstrate a novel single shot autocorrelation technique for characterization of ultrashort pulses. Unlike existing single shot autocorrelation techniques, our new technique is capable of characterizing optical pulses over a femtosecond to picosecond pulse-width range. Our technique uses a grating at the entrance of the system, introducing a Transverse-Time- Delay (TTD) into the reference pulse. The pulse front in the resulting field is decoupled from the wave front. The signal pulse to be characterized and the TTD reference pulse are mixed in a nonlinear optical crystal, producing a second harmonic field whose transverse spatial extent is proportional to the signal pulse width. Since our technique allows for decoupling of the time delay from the propagation direction (unlike the commercial single shot autocorrelators), we can select the angle between the intersecting pulses to satisfy the phase matching conditions, achieving best efficiency while setting the resolution independently in the orthogonal direction. In addition, by controlling the slope of the TTD, the system can adapt to a wide range of input pulse widths. In this paper we will present the basic principles as well as experimental results for this new autocorrelation technique.