At three end stations at BESSY II with cutting-edge angle-resolved photoemission spectroscopy (ARPES) instruments, we are able to study various electronic properties of quantum materials due to the versatile functions of our end stations. ARPES 1^3 station provides the highest energy resolution (~1 meV) at ultimately low sample temperatures (~1 K). ARPES 1^2 station allows for a broad...
We investigate the spin dynamics driven by terahertz magnetic fields in epitaxial thin films of
cobalt in its three crystalline phases. The terahertz magnetic field generates a torque on the magnetization which causes it to precess for about 1 ps, with a sub-picosecond temporal lag from the driving force. Then, the magnetization undergoes natural damped THz oscillations at a frequency...
BOREAS beamline 29 at ALBA Synchrotron Light Facility is a soft X-ray beamline dedicated to polarization-dependent spectroscopic investigations of advanced materials, enabling techniques such as x-ray magnetic circular and linear dichroism (XMCD, XMLD), and soft x-ray resonant scattering (including reflectometry, gisaxs, holography and coherent imaging) [Barla et al., J. Synchrotron Rad....
LOREA, the ninth beamline of the ALBA synchrotron radiation source, started its operation in 2021 and is dedicated to electronic structure investigation of quantum materials by means of Angle Resolved Photo-Emission Spectroscopy (ARPES).
The photon energy range of the beamline (10-1000 eV) with continuously variable polarization and resolving power of more than 10ˆ4 in the whole range allows...
A high-temperature superconducting (HTS) undulator is under development at the Paul Scherrer Institut. This device equipped with HTS bulks is a novel technology to generate short period and high strength magnetic field. For medium-energy synchrotron storage rings, this is a promising option to increase tremendously the photon flux in hard X-ray domain. The experiment for a sample consisting of...
Mammalian Rhodopsin, a prototype of the largest druggable G Protein-Coupled Receptors family (GPCRs), is our light receptor for night vision. Upon photon absorption, its chromophore 11-cis retinal undergoes one of the fastest events in biology, which happens in the femtosecond range, the isomerization into the agonist form, all-trans retinal. We have developed a new crystal form of rho-dopsin,...
We recently developed nano-engineered, high Z compound semiconductors avalanche photodiodes and quantum-well detectors for ultra fast single photon detection in a wide wavelength. The availability of ultra fast photon detection is of paramount importance in all fields of science and technology. These detectors are based on quantum well technology in particular on GaAs/AlGaAs hetero-junctions...
The advancement of quantum technologies is expected to pave the way for practical Quantum Computing (QC). Practical QC should provide solutions to certain problems, superior to those offered by the classical computational paradigm. The QC field is [in development][1] but has not taken its final form yet. In an attempt to define requirements for its practical use, this research reviews the...
Ultrafast, ultra-low noise X-ray detectors based on Avalanche PhotoDiodes (APDs) are crucial elements in scientific contexts such as Synchrotron Radiation facilities and Free Electron Lasers. APDs have been traditionally based on silicon, a mature and solid technology with adequate performance up to the X-ray range. However, the advent of ultimate light sources set more stringent requirements...
The recently commissioned Extremely Brilliant Source (EBS) has substantially enhanced the nano probe capacities at the ESRF. Nano diffraction imaging has been boosted by these capacities to improve in spatial resolution reaching length scales relevant for a variety of materials that are candidates for quantum computing. As band structure properties in all semiconductors sensibly depend on...
Quantum materials exhibit unique physical phenomena, especially if grown in ultra-thin films or in heterostructures with other materials. We have built and operated a dedicated UHV facility where multiwavelength Pulsed Laser Deposition can synthesize quantum materials and directly deliver the atomic-layer controlled samples to an all-resolved photoemission apparatus (SP-ARPES) and to an...
Implementing all-resolved photoelectron spectroscopy (ARPES, SpinPES, SPARPES) with temporal resolutions, in pump-probe mode, requires dedicated facilities capable to deliver ultrashort photon pulses (~100 fs) in the Extreme Ultraviolet (EUV) region with an adjustable repetition rate up to the MHz range to provide the necessary statistics while maintaining the photoexcitation density safely in...
This contribution presents the femtosecond pump-probe laser infrastructure of the Soft X-ray Port (SXP) scientific instrument at the European XFEL. This experimental platform is primarily designed for time- and spin-resolved photo-electron spectroscopy, but investigations of complex chemical and bio-inorganic molecular systems by means of fluorescence spectroscopy as well as research on highly...
The effect of pulse wavefront (WF) distortion ranges from change in the radiation deposition mechanism, to inability to reach diffraction limited foci, and limitations in spectral correlations between spectrometers. The effect goes well beyond 'bad quality' beam and may determine the capability and the scientific goal of the experiment altogether. At the same time, the technique used to...
Quantum materials nowadays hold the key to develop new technologies that satisfy the increasing societal demands in terms of communication and data handling while being sustainable and ecofriendly. The technological development relies on the ultimate understanding of the materials properties as well as on the definition of new pathways to control their properties. Femtosecond time-resolved...
Training is becoming an increasingly important topic to facilitate the work of scientists at accelerator-based photon sources and also to introduce young scientists to specific areas such as modern quantum technologies. One of the goals of ExPaNDS (European Open Science Cloud (EOSC) Photon and Neutron Data Service) is to train research scientists in order to better understand the issues,...
In the last decades, advances in the generation and manipulation of ultrashort light pulses allowed photon and electron spectroscopies to access the time domain in the consolidated pump-probe scheme. Refined in several aspects, the technique has demonstrated its versatility in accessing the dynamics and transient states produced by impulsive photoexcitation on various physical systems, opening...
