The Attosecond Light Pulse Source (ALPS) facility of the pan-European Extreme Light Infrastructure (ELI) project was designed as a laser-based research infrastructure in which light pulses of few optical cycles in the infrared or mid-infrared spectral range are used for basic and applied research. In particular, these pulses will be used as the driving source for generating even shorter extreme ultraviolet (XUV) pulses with durations as short as a few tens of attoseconds.
All the six major laser systems available at ELI-ALPS were designed for stable and reliable operation, while featuring unique pulse parameters, such as unprecedented photon flux and extreme bandwidths. Each laser will run synchronized to the central facility clock, while femtosecond synchronization on target will be ensured by a dedicated timing system. Experimental beam time will be provided with uninterrupted operation of the primary driving lasers and associated secondary sources for at least eight hours per day.
The primary focus of ELI-ALPS is the generation of the best quality attosecond XUV pulses in terms of pulse energy, repetition rate and photon energy. This goal is only achievable using the highest quality primary sources and expertly designed, innovative high-harmonic beamlines. The generation of high flux attosecond pulse trains and isolated attosecond pulses is targeted using Gas-based or Surface Plasma-based High Harmonic Generation. These secondary sources will feature dedicated target end stations (e.g. Reaction Microscope, Condensed matter end station, Velocity Map Imaging Spectrometer and Magnetic Bottle Electron Spectrometer) enabling users to perform state-of-the-art experiments.
Experimental activities in the building complex started in 2018 with the installation of two 100 kHz repetition rate laser systems: the mid-infrared laser (MIR) and the first High Repetition Rate laser (HR1). They successfully served almost ten commissioning user experiments with external collaborators, for the investigation of phenomena such as electron migration in water, electron rescattering induced K-shell fluorescence, photoionization of droplets, photon statistics in harmonic generation in band gap materials etc., altogether for 51 operational weeks in 2018. In 2019 we expect to extend commissioning experiments to the SYLOS laser as well as to, at least, two attosecond and THz beamlines. The first attosecond beamline, driven by HR1 and dedicated to the investigation of ultrafast pheonemena in gas targets, is to be inaugurated mid 2019. In addition, the operation of the THz laboratory, as well as nanoplasmonic experiments are planned for 2019.
The major research equipment of the Attosecond Light Pulse Source of the Extreme Light Infrastructure (ELI-ALPS) are driven by laser pulses of few cycle duration operating in the 100 W average power regime. The peak power and the repetition rate span from 1 TW at 100 kHz up to PW at 10 Hz. The systems are designed for stable and reliable operation, yet to deliver pulses with unique parameters, especially with unmatched fluxes and extreme bandwidths. This exceptional performance will enable the generation of secondary sources with exceptional characteristics, including light sources ranging from the THz to the X-ray spectral ranges, and particle sources.
The experimental activities in the building complex to be inaugurated early 2017 will start with the installation of the two 100 kHz repetition rate, CEP stabilized lasers in May 2017. The MIR laser produces 0.15mJ, shorter than 4-optical-cylce pulses tunable between 2.5-3.9 µm. The first stage of the HR laser will provide pulses around 1 µm with 1 mJ energy and pulse duration less than 6.2 fs. The systems will be optically synchronized to each other with a temporal jitter below 1 fs.
Along with the installation of the lasers, we will also start the assembly of the high harmonic beamlines and the THz laboratory, as well as nanoplasmonic experiments. The XUV bursts of light with attosecond duration are expected to be generated by the end of 2017.
Femtosecond laser-induced damage threshold (LIDT) measurements for different optical components are well studied for a set of laser pulse repetition rates spanning the range between 1 Hz and 1 kHz. Recent years saw the advent of high-repetition-rate femtosecond systems with relatively high pulse energy. Therefore investigation of LIDT in the MHz region is essential. We performed several comparative femtosecond LIDT measurements on typically used ultrafast optical elements with different Ti:Sapphire laser systems having substantially different pulse repetition rates (a 1 kHz regenerative amplifier and a 4.3 MHz long-cavity oscillator) and found a substantially lower MHz LIDT threshhold.
Extreme Light Infrastructure (ELI), the first research facility hosting an exawatt class laser will be built with a joint
international effort and form an integrated infrastructure comprised at last three branches: Attosecond Science (in
Szeged, Hungary) designed to make temporal investigation at the attosecond scale of electron dynamics in atoms,
molecules, plasmas and solids. High Field Science will be mainly focused on producing ultra intense and ultra short
sources of electons, protons and ions, coherent and high energetic X rays (in Prague, Czech Republic) as well as laserbased
nuclear physics (in Magurele, Romania). The location of the fourth pillar devoted to Extreme Field Science, which
will explore laser-matter interaction up to the non linear QED limit including the investigation of vacuum structure and
pair creation, will be decided after 2012. The research activities will be based on an incremental development of the light
sources starting from the current high intensity lasers (APOLLON, GEMINI, Vulcan and PFS) as prototypes to achieve
unprecedented peak power performance, from tens of petawatt up to a fraction of exawatt (1018 W). This last step will
depend on the laser technology development in the above three sites as well as in current high intensity laser facilities.
Carrier-envelope phase-stabilized laser pulses brought significant advances in investigating laser-solid interactions, as well, with the potential of revealing carrier dynamics in solids on unprecedented time-scales. More specifically, multi-photon induced photoemission from metals proved to be sensitive to the waveform of few-cycle pulses, however, underlying mechanisms are not fully understood. Combining surface plasmonic effects with photoemission demonstrates a potentially more promising approach to investigate laser-surface interactions induced by few-cycle pulses. Numerical results from a simple model on this phenomenon are presented. Related to this, previously unaddressed carrier-envelope phase phenomena in the vicinity of the focus are also considered.
Conference Committee Involvement (2)
Research Using Extreme Light: Entering New Frontiers with Petawatt-Class Lasers
15 April 2013 | Prague, Czech Republic
ELI: Ultrarelativistic Laser-Matter Interactions and Petawatt Photonics