Fig. 2: Experimental characterization of the high-performance EUV—soft X-ray spectrometer—monochromator using high harmonic generation light.

Intense femtosecond near-infrared laser pulses of 1036 nm or 800 nm are focused into a gas cell filled with argon to generate EUV light or helium for X-ray light. The coherent high harmonic beams are imaged in a 2f–2f configuration by a toroidal mirror with a focal length of f = 400 mm, then spectrally resolved by a grating set at an incident angle γ = \(6^\circ\). The conical diffraction is detected by an EUV CCD camera with a pixel size of 20 × 20 μm