**6. Conclusions**

**Figure 14.** Simulation of the compression of a XUV pulse with the parameters of **Table 3**.

A schematic view of an experiment using compressed attosecond pulses is shown in **Figure 15**. The XUV attosecond pulses are generated on a gas jet in a vacuum chamber and are intrinsically chirped. The XUV radiation is generated with the intrinsic attosecond chirp. Different wavelengths travel in different paths inside the compressorthat compensates forthe

Attosecond pulses are generated in different XUV spectral windows, depending on the

ed in the 50–120 eV region. Attosecond pulses are generated from the short trajectory

ultrafast laser intensity, radiation is generat‐

intensity, radiation is generat‐

**5.1. Example of application to attosecond pulses**

240 242High Energy and Short Pulse Lasers

chirp and reduces the time duration of the pulse.

**Figure 15.** Schematic of the attosecond compressor.

interacting gas. Using argon and ≈2⋅1014 W/cm<sup>2</sup>

ed in the 25–55 eV region, while with neon and ≈6⋅1014 W/cm<sup>2</sup>

The use of diffraction gratings to manipulate the spectral phase of XUV ultrashort pulses has been discussed. The system consists of two gratings to introduce the required phase chirp. Both the classical and the off-plane geometries have been discussed.

Both a simple design with two plane gratings working in collimated beam and a more complex design with two plane gratings and an intermediate focal point have been discussed. Both designs are tunable in wavelength range to cover the whole spectral extension of the source and operate at different wavelengths; furthermore, once the operating wavelength has been chosen, the GDD is tunable to compensate for the actual pulse chirp.

The use of elements at grazing incidence makes the system particularly suitable for the application to CPA of intense FEL pulses and to compression of attosecond pulses, playing an important role for the photon handling and conditioning of future ultrashort sources.
