Chair: Ursula Keller, ETH Zürich, Switzerland

  • Craig Benko
  • Tadas Balciunas
  • Jens Limpert
  • Eric Constant
  • Alexander Guggenmos

#68, 15:30 – 16:00 Extreme ultraviolet frequency combs, CRAIG BENKO AND JUN YE, Extreme ultraviolet frequency combs are a versatile tool for precision spectroscopy, strong field physics, physical chemistry and condensed matter physics. Recent work demonstrated extreme ultraviolet radiation with a coherence time greater than 1 second, far exceeding any other source of extreme ultraviolet radiation. Further, the femtosecond enhancement cavity techniques employed for extreme ultraviolet frequency combs were applied to rotationally excite molecular samples to perform high-order harmonic generation in aligned molecules.

#69, 16:00 – 16:15 A compact single cycle driver for strong field applications based on a selfcompression in a Kagome fiber, T. BALCIUNAS, G. FAN, S. HAESSLER, C. FOURCADE-DUTIN, T. WITTING, A.A. VORONIN, A. M.ZHELTIKOV, F. GEROME, G.G. PAULUS, A. BALTUSKA, AND F. BENABID, We report on Kagome fiber based self-compression of 100 μJ IR pulses to single cycle duration and demonstrate HHG in an integrated scheme  which allows a compact isolated attosecond XUV source implementation above 50 eV.

#70, 16:15 – 16:30 Energetic sub-2 cycle pulses at high repetition rates: towards a new source for attoscience, S. HÄDRICH, J. ROTHHARDT, R. KLAS, G. TADESSE, A. HOFFMANN, M. KREBS, A. KLENKE, Z. VÁRALLYAY, A. DROZDY, E. CORMIER, J. LIMPERT, AND A. TÜNNERMANN, Double stage nonlinear compression in gas-filled hollowcore fibers is applied to femtosecond fiber lasers leading to compression of 0.6 mJ, 250 fs pulses to 0.2 mJ, sub-2 cycle (6.1 fs at 1030 nm) pulses at 43 kHz repetition rate (8.6 W of average power). Transmitting 712 W of average power from a kilowatt cw fiber laser with excellent beam quality and stability demonstrates the outstanding scaling capability of this approach. We will propose appropriate few-cycle optics and ideas for the stabilization of the carrier envelope phase making this approach a promising route towards >100W, multi-mJ, sub-2cycle source for attoscience.

#71, 16:30 – 16:45 Optimization and control of high power high-order harmonics generated with a 50W, 100 kHz, Yb femtosecond laser system, A. CABASSE, CH. HAZERA, L. QUINTARD, E. CORMIER, S. PETIT, AND E. CONSTANT, We generate high order harmonics in the tight focusing regime with a high power, high repetition rate laser system and define optimizing conditions to maximise the XUV flux. Despite the 50 W, high power copropagating fundamental laser, the emitted XUV beam is afterward collected, filtered and imaged with a spectrometer onto a detector that allows us to characterize the useful output XUV flux. We observe at the output of the imaging spectrometer that a XUV flux higher than 0.1 μW can be obtained at focus and be useful for experiments at high repetition rate.

#72, 16:45 – 17:00 Cr/Sc multilayer mirrors for attosecond pulses at 145 eV, A. GUGGENMOS, M. JOBST, M. OSSIANDER, S. RADÜNZ, J. RIEMENSBERGER, M. SCHÄFFER, A. AKIL, C. JAKUBEIT, P. BÖHM, S. NOEVER, B. NICKEL, R. KIENBERGER, AND U. KLEINEBERG, The development of attosecond soft X-ray sources towards photon wavelengths below 10 nm is also driving the development of suited broadband multilayer optics for shaping attosecond pulses. We present our achievements in utilizing optimized ionbeam deposited Cr/Sc multilayer mirrors for the generation of single attosecond pulses at 145 eV. Isolated attosecond pulses have been measured by soft X-ray-pump/NIRprobe electron streaking experiments and characterized using FROG/CRAB. The results demonstrate that Cr/Sc mirrors can be used as efficient attosecond optics for reflecting 600 attosecond pulses at a photon energy of 145 eV, which is a prerequisite for present and future attosecond experiments.