High Harmonic Generation (HHG) is a process used to generate short wavelength (typically < 100 nm) light by focussing intense short laser pulses in the NIR into typically a gas from a gas jet inside a vacuum chamber. Generating intensities of 1014 W/cm² creates an electric field of the laser pulse on the order of the electric field inside the atom, creating a large enough disturbance of the atomic field to enable an electron to leave via tunnelling and recombine with the atom, giving off its energy gained from the laser field during recollision as radiation in the UV and soft X-Ray region.
Using CEP stable pulses driving the high order harmonic generation process results in the emission of a shot to shot in phase attosecond pulse train. The CEP dependent effects become more pronounced the shorter the driving pulse, where using a few cycle CEP stable driving pulse is able to generate an isolated attosecond pulse. Whether a single or double attosecond pulse is generated per driving pulse depends on the CEP phase of the few cycle driving pulse (cos-like or sine-like shape).
The venteon OPCPA provides such few cycle CEP stable optical pulses for driving HHG. For measurements depending on good statistics, the MHz high repetition rate enables much faster data acquisition using the customers HHG setup, using CEP stabilised driving pulses when needed.