Optical concept of a compressor for XUV pulses in the attosecond domain

The design of a grating compressor for attosecond pulses in the extreme-ultraviolet region is presented. The instrument adopts a double-grating configuration with grazing-incidence gratings in the off-plane mount. The configuration preserves the length of the optical paths of the different rays coming from the source at the same wavelength, while it realizes a controlled dispersion of the length of the optical paths of rays at different wavelengths. The corresponding group-delay dispersion can be either positive or negative, depending on the geometry of the system. As a test case, the application to the compression of an attosecond pulse in the 50-100 eV region is discussed.