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In recent years, femtosecond extreme-ultraviolet (XUV) and x-ray pulses from free-electron lasers have developed into important probes to monitor processes and dynamics in matter on femtosecond-time and angstrom-length scales. With the rapid progress of versatile ultrafast x-ray spectroscopy techniques and more sophisticated data analysis tools, accurate single-pulse information on the arrival time, duration, and shape of the probing x-ray and XUV pulses becomes essential. Here, we demonstrate that XUV pulses can be converted into terahertz electromagnetic pulses using a spintronic terahertz emitter. We observe that the duration, arrival time, and energy of each individual XUV pulse is encoded in the waveform of the associated terahertz pulses, and thus can be readily deduced from single-shot terahertz time-domain detection.

A high repetition rate, optical-parametric chirped-pulse amplifier system and high-harmonic-generation source is presented for photoelectron spectroscopy experiments spanning an ultra-wide frequency range from Terahertz to the extreme-ultraviolet range between 21.7 and 50 eV.

In this contribution, we discuss the opportunities arising from the spectrally dense, narrow band, tunable, high repetition rate THz source; TELBE; which recently started user operation. The user facility includes an end station for transient Faraday/MOKE and THz emission spectroscopy and is also equipped with a superconducting split-coil cryo-magnet. Thereby the dynamics of selectively driven resonances in the frequency range between 0.1 and 1.2 THz can be followed with a femtosecond sub THz-cycle time resolution at temperatures between 3 and 300 K and in magnetic fields up to 10T.

We report on highly efficient THz high harmonic generation in graphene up to 7th order, at room temperature and under ambient conditions. The process is facilitated by dynamical electron heating and cooling in THz fields.