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We performed a detailed measurement of the Gouy phase of an infrared beam reflected on a drilled mirror and demonstrated its influence on attosecond measurements with two spatially separated targets.
We present a high-power mid-infrared OPCPA system generating ultra-broadband pulses centered at 2.2 μm with a bandwidth supporting pulse compression to 15 fs. We achieve a record average power of 9.1 W at 100 kHz.
Non-dipole effects in strong-field ionization are observed at high laser intensities and/or long wavelengths that both lead to high kinetic energies of the photoelectrons [1]. At longer wavelengths, the electron is influenced by the magnetic field component of the laser field even at moderate intensity [2]. In cases where the Coulomb field can be neglected, the magnetic field component is responsible...
High-power and few-cycle mid-IR laser sources are of great interest for their application in strong-field physics and attosecond science [1, 2]. We present an ultra-broadband optical parametric chirped-pulse amplification system (OPCPA) achieving 9.1 W of average power at a repetition-rate of 100 kHz, with an optical bandwidth centred at 2.2 μm and spanning 1000 nm. To the best of our knowledge, this...
Combining attosecond transient absorption spectroscopy in polycrystalline diamond with theoretical models we were able to identify dominant signatures from the dynamical Franz-Keldysh effect for excitations high into the conduction band and on few-femtosecond time scales.
Photoemission delays from copper (111) are measured in an attosecond pump — infrared probe experiment. The influence of the probe pulse and the validity of the Fresnel equations on atomic length and time scales are investigated.
We study strong-field ionization with elliptically polarized mid-IR pulses beyond the long-wavelength limit of the dipole approximation. Rescattering creates a sharp structure in 3D photoelectron momentum distributions influenced by non-dipole effects.
For the first time, we implemented both RABBITT and attosecond energy streaking using an AttoCOLTRIMS apparatus and exploit its advantages to determine energy- and angle-resolved single-photon ionization time delays for different noble gases.
We present a proof-of-principle of broadband, non-collinear quasi-phase-matching in a hybrid OPCPA system. It employs a combination of quasi-phase-matching and group-velocity-matching in a MgO:PPLN delivering 3.4-µm, 17.2-µJ, 43.1-fs pulses at 50 kHz repetition-rate.
We investigated quarter-laser-cycle oscillations in the transient absorption signal of attosecond pulse trains and infrared pulses interacting in helium. We discuss their physical origin and show their usefulness for experimental delay-zero calibration in attosecond science.
We present an ultra-broadband OPCPA system operating at 3.4 µm delivering 41.6-fs pulses. The average output power is currently 600 mW, corresponding to 12 µJ of pulse energy at a repetition rate of 50 kHz.
Strong field ionization momentum distribution contains much information. The angular distribution indicates real tunneling delay time, the center shows ellipticity dependent Coulomb effects, and the longitudinal momentum spread challenges the assumption of zero initial momentum.
Ionization with a few-cycle mid-infrared laser field results in an electron momentum shift directed opposite to the beam pressure. This result represents a breakdown of the dipole approximation, in contrast to previous observations of photon-momentum-transfer.
Implementing RABBITT on solids for the first time, we record energy-resolved absolute photoemission delays from noble metal surfaces. The structure of the observed delays in Ag(111) and Au(111) is inconsistent with previously promoted models.
We combine an attosecond beamline with a 3D momentum imaging spectrometer to achieve coincidence pump probe experiments with unprecedented attosecond time-resolution. Besides technical details, first coincidence and pump-probe experiments are presented.
We present a comprehensive study of the physics and design of OPCPA based on chirped quasi-phase-matching, identifying subtle parametric processes occurring in these devices, and how they were addressed in our latest mid-IR OPCPA result.
We present a study of features in photoelectron momentum distributions from strong-field ionization of noble gases for few-cycle pulses in the mid-infrared regime and assign characteristics to their classical and quantum mechanical origin.
The photoelectric effect was fundamental in the development of quantum mechanics and has become a widespread tool for the study of electronic structure in diverse systems. However, its temporal aspect - even in atoms — still lacks complete understanding. The advent of attoscience has provided experimental tools to address this question. Both attosecond streaking [1] and RABBITT [2] were applied to...
The temporal evolution of the dipole response of a system excited by an electromagnetic field usually is not accessible with traditional spectroscopy. Only the time-integrated dipole response (TIDR) is detected. Here, we investigate the case of the off-resonant excitation of a quantum-mechanical two-level system (TLS) where the TIDR is expected to be zero. Our time-frequency representation of the...
Quasi-phasematching (QPM) has been utilized for a wide variety of nonlinear-optical devices, for applications such as ultrafast optics and quantum optics [1, 2]. A key advantage of this technology is its high degree of engineerability, enabled by the freedom in fabricating QPM gratings with a wide range of periods and lengths. This enables, for example, pulse compression via second-harmonic generation,...
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