AS-2
AS-2 is a second-generation attosecond beamline with extended capabilities compared to AS-1. The key innovation here is a separation of the beam delivering the attosecond XUV pulse from its NIR driver beam in a Mach-Zehnder-type interferometric configuration incorporated in a manipulation chamber between HHG chamber and experimental chamber. This permits separate manipulation of both beams, including frequency conversion of the NIR pulse to either lower (mid-IR) or higher (UV) frequencies, and thereby tailoring the characteristics of the pump or probe pulses to the needs of the atomic / molecular system under scrutiny.
We are incorporating a second-harmonic (SH) converter as well as UV/VUV frequency conversion unit for generating multi-nanojoule-energy few-cycle violet (~3.5eV) and UV/VUV (5-30eV) pulses with few-fs-to-sub-fs durations. These come in combination with isolated sub-100-as XUV (70-150eV) pulses and serve several purposes. The violet SH beam is coherently added to the IR fundamental and used for confining optical field ionization to a single sub-fs step for triggering electron dynamics within several hundred attoseconds via field ionization. The few-fs/sub-fs UV/VUV pulses will launch electron wavepackets and trigger attosecond electron motion in atoms and molecules. This novel beamline architecture also invites to incorporate an optical waveform synthesizer in the Mach-Zehnder interferometer, for steering electron wavepackets.
In all these scenarios, the asec XUV pulses can be used for probing the unfolding dynamics by attosecond photoelectron, ion, or absorption spectroscopy. The beamline is seeded with few-cycle NIR pulses from FP-2 or FP-3
and equipped with all the necessary detection systems to these ends: electron and ion spectroscopy with a combined time-of-flight electron spectrometer and a reflecton-type ion-mass spectrometer and transmitted XUV photon spectrometry. Attosecond diagnostics: optical-field-driven streak camera and attosecond light wave sampling, online carrier-envelope-phase monitoring.
contact: M. Schultze, R. Kienberger
and equipped with all the necessary detection systems to these ends: electron and ion spectroscopy with a combined time-of-flight electron spectrometer and a reflecton-type ion-mass spectrometer and transmitted XUV photon spectrometry. Attosecond diagnostics: optical-field-driven streak camera and attosecond light wave sampling, online carrier-envelope-phase monitoring.
contact: M. Schultze
, R. Kienberger
More reading:
Versatile apparatus for attosecond metrology and spectroscopy
M. Fieß, M. Schultze, E. Goulielmakis, B. Dennhardt, J. Gagnon, M. Hofstetter, R. Kienberger, and F. Krausz Rev. Sci. Instr. 81, 093103 (2010)
M. Fieß, M. Schultze, E. Goulielmakis, B. Dennhardt, J. Gagnon, M. Hofstetter, R. Kienberger, and F. Krausz Rev. Sci. Instr. 81, 093103 (2010)
Fig. 1. The AS-2 beamline. (© thn)
Fig. 2. View into the experimental chamber of the attosecond beamline AS2: Atomic gas streams from a nozzle into the interaction volume where attosecond XUV pulses and few-cycle laser pulses are employed for pump probe experiments. Photoelectrons are detected by a time of flight detector (TOF) mounted from the top. (© thn)