Figure 3

Theoretical (A–C) and experimental spectrograms at 800 nm (D–F) for FSH (B,E) and TSH (C,F) for pure phase shaping. In (A), a pure TOD of 150000 fs³ was added to a 33 fs TL fundamental pulse. In the experiment (D), additional higher order distortion terms are present. In FSH (B,E), the butterfly shape is nicely preserved while it is completely washed out in TSH (C,F). The experimentally retrieved phases are given in (G). The blue line showing the phase obtained through FSH nicely follows the shape of the fundamental (red line). The SH phase stroke is larger by a factor of 2 as expected from Eq. 5. This is evident from the different ranges for the left and right phase axes which refer to the second harmonic and the fundamental, respectively. The cyan line corresponding to TSH, on the contrary, exhibits a completely different behaviour. Thus, arbitrary phase functions can only be transferred via FSH. Even deep-UV shaping is possible. A TL pulse at 207 nm is shown in (H) and a pulse train achieved by applying a sine-phase function to the 830 nm input pulses in (I). Incidentally, these are the first FROG trace ever taken at such low wavelengths.