High repetition rate, high photon flux VUV source

Femtosecond laser sources emitting in the Vacuum Ultraviolet (VUV) are essential tools enabling tabletop time and Angle Resolved Photo-Emission Spectroscopy (tr-ARPES) experiments in solids [1]. Here, we report a VUV laser source based on the ninth harmonic generation of an industrial grade Yb-doped fiber amplifier delivering 500 fs-long pulses at 1030 nm and 100 kHz of repetition rate. The experimental setup is shown in Figure 1, on the left. The ninth harmonic of the 1030 nm laser beam is a result of three stages of frequency up-conversion. The fundamental beam undergoes two frequency up-conversions in BBO crystals generating a 343 nm $(3\omega)$ laser pulses. These pulses are further sent to a Third Harmonic Generation (THG) stage based on a xenon-filled cell, yielding a beam at 114 nm (10.8 eV) (9ω). A detection chamber composed by a spherical mirror and a grating is designed to filter out the 343 nm and detect the 114 nm radiation. The 114 nm photon flux is estimated by measuring the drain current from the surface of a gold target.