Paradis, Clément

, Labaye, François, Gaponenko, Maxim, Wittwer, Valentin, Diebold, A, Paradis, Clément, Modsching, Norbert Paul, Merceron, Loïc, Emaury, F, Graumann, I.J, Phillips, C.R, Saraceno, C.J, Kränkel, C, Keller, Ursula, Südmeyer, Thomas

We demonstrate a compact extreme ultraviolet (XUV) source based on high-harmonic generation (HHG) driven directly inside the cavity of a mode-locked thin-disk laser oscillator. The laser is directly diode-pumped at a power of only 51 W and operates at a wavelength of 1034 nm and a 17.35 MHz repetition rate. We drive HHG in a high-pressure xenon gas jet with an intracavity peak intensity of 2.8×10¹³  W/cm² and 320 W of intracavity average power. Despite the high-pressure gas jet, the laser operates at high stability. We detect harmonics up to the 17th order (60.8 nm, 20.4 eV) and estimate a flux of 2.6×10⁸  photons/s for the 11th harmonic (94 nm, 13.2 eV). Due to the power scalability of the thin-disk concept, this class of compact XUV sources has the potential to become a versatile tool for areas such as attosecond science, XUV spectroscopy, and high-resolution imaging.

, Modsching, Norbert, Paradis, Clément, Labaye, François, Gaponenko, Maxim, Graumann, Ivan J, Diebold, Andreas, Emaury, Florian, Wittwer, Valentin, Südmeyer, Thomas

We demonstrate the first Kerr lens mode-locked Yb:CaGdAlO₄ (Yb:CALGO) thin-disk laser oscillator. It generates pulses with a duration of 30 fs at a central wavelength of 1048 nm and a repetition rate of 124 MHz. The laser emits the shortest pulses generated by a thin-disk laser oscillator, equal to the shortest pulse duration obtained by Yb-doped bulk oscillators. The average output power is currently limited to 150 mW by the low gain and limited disk quality. We expect that more suitable Yb:CALGO disks will enable substantially higher power levels with similar pulse durations.

, Modsching, Norbert, Drs, Jakub, Fischer, Julien, Paradis, Clément, Labaye, François, Gaponenko, Maxim, Kränkel, Christian, Wittwer, Valentin, Südmeyer, Thomas

We investigate power-scaling of a Kerr lens mode-locked (KLM) Yb:Lu₂O₃ thin-disk laser (TDL) oscillator operating in the sub-100-fs pulse duration regime. Employing a scheme with higher round-trip gain by increasing the number of passes through the thin-disk gain element, we increase the average power by a factor of two and the optical-to-optical efficiency by a factor of almost three compared to our previous sub-100-fs mode-locking results. The oscillator generates pulses with a duration of 95 fs at 21.1 W average power and 47.9 MHz repetition rate. We discuss the cavity design for continuous-wave and mode-locked operation and the estimation of the focal length of the Kerr lens. Unlike to usual KLM TDL oscillators, an operation at the edge of the stability zone in continuous-wave operation is not required. This work shows that KLM TDL oscillators based on the gain material Yb:Lu₂O₃ are an excellent choice for power-scaling of laser oscillators in the sub-100-fs regime, and we expect that such lasers will soon operate at power levels in excess of hundred watts.