Temporal self-reconstruction of few-cycle nondiffracting wavepackets

摘要

The temporal self-reconstruction of pulsed Bessel-like needle beams was studied. Arrays of nondiffracting sub-7-fs needle beams were shaped from Ti:sapphire oscillator pulses by programming multiple axicons in a phase-only spatial light modulator. Defined distortions in the time domain were induced by local spectral filtering. By differently shading parts of selected sub-beams, the self-reconstruction was analyzed under variable conditions. Pulse duration maps were measured with two-dimensional second order autocorrelation based on the Shack-Hartmann sensor principle of wavefront division. Completely distorted pulses were found to have a pulse duration of ＞13 fs whereas partially distorted sub-beams returned to pulse durations close to the initial ones. Specific applications are proposed.