“Pulse shaping includes anything that changes the pulse shape”

As a motivation the following fundamental aspects are marked out:

- Coherent control of atomic, molecular and photoinduced multielectron dynamics;

- Light-matter interaction in terms of filamentation and X-ray generation;

- Advanced driving of XUV and HHG generation.

The pulse shape manipulation is a linear filtering process. Altering any of pulse’s parameters changes the pulse envelope. In the time domain the filter action of the shaper is represented by an impulsive response function h(t); The output electric field Eout(t) is the convolution of the input Ein(t) and the response function h(t). Optical modu-lators are too slow to deliver the filter with instantaneous temporal response. Alternatively the manipulation of the spectral amplitude or phase (or both) of the pulse will lead in turn to the required modulation in the time domain. The spectral modulation with appro-priate H(w) and phase f(w) functions will lead to the correct output signal compatible with the original spectral width. The task is turned to frequency-disperse the pulse in space and modulate the spectrum and spectral phase by creating a spatially varying transmission functions.

Two types of pulse shapers are in use:

To overcome the limitation imposed on the accessible pulse energy by damage thresholds of used optical modulators, a scheme of adaptive pulse amplification is choosen: first pulse-shape, after that amplify, then measure and feedback on the FROG, Spider or Tadpole to control and to optimise the targeting result. The whole system layuot is presented here

Meilenstones:
· Amplified radiation with programmed tailoring by phase modulators of femtosecond pulses;
· Active and passive methods for spatial wave-front corrections for diffracted limited beam propagation;
· Generation of pulse sequences with adjustable temporal separation;
· Ultra-short pulse generation with around Fourier-limited pulse duration;
· Pulse compression and frequency conversion with a use of the novel methods (f.i. filamentary pulse shaping in noble gases)