28 Nov 2018

2018: Exciting times at ELI-ALPS

Károly Osvay
Research Technology Director, ELI-ALPS

So far, 2018 has been a very exciting year in the lifespan of ELI-ALPS. Károly Osvay, Research Technology Director at the Hungarian pillar of ELI, talks us through some of the major milestones that have been achieved in the past months.

A lot has happened since ELInes last caught up with Osvay in May 2017. ‘Let me start with the implementation milestones we have achieved since then. Three of our primary laser systems have been installed and are operational since the beginning of this year: the first High Repetition Rate Laser, the Mid-infrared laser, and the first Terahertz pump laser. Furthermore, we have started installing the petawatt laser in May this year, so we are now working towards reaching full specifications in the coming months. And the vacuum assembly of the first attosecond beamline has been completed very recently. My colleagues are starting with the optical alignment as we speak. As the High repetition Rate laser has been operational, we can start generating the first harmonics in the beginning of 2019, which then will be perfectly according to plan.’

Ramping up the Facility
The first three laser systems are not only operational, but also have already been used in the first commissioning experiments by expert users in the framework of collaboration MoUs with ELI-ALPS. During the past six months, four different international experimental groups have been working at the facility, mainly with the Mid-infrared laser and in part with the first High Repetition Rate Laser. These experiments are crucial in ramping up the Facility, Osvay states. ‘Though these are not official milestones as mentioned in the commissioning documentation, I think for the Facility as a whole it is very important that external scientists meet here in experiments built on the collaboration agreements.’

These first four experiments with the MIR laser have been rather successful, Osvay says with pride. ‘During the first commissioning user experiment that took place last February, a team from FORTH, Crete, even managed to demonstrate a proof of concept for a new type of quantum statistical spectrometry. This makes it possible to do spectral measurements in the XUV or even the X-ray regime without the need for specialized equipment. The paper on this result will soon be published.
The second experiment conducted by a joint team of Aarhus University and Freiburg University showed some nice results with the Mid-infrared laser, which was used to study photoionization of helium droplets. The third team came from the Hebrew University in Jerusalem and looked at atomic inner shell excitation. They left last September, and a team from France came in to conduct experiments to deduce how to make the MIR pulses shorter. Currently, the MIR system provides 4 optical cycles of 40 femtoseconds per pulse. We want to go to two cycles of pulses below 30 femtoseconds. The first results of this team have already led to a modification of the fiber-based hardware for this laser.’ Besides these four experiments that have been carried out so far, two more experiments are planned for the remainder of this year. Moreover, a commissioning user experiment from a team of ETH Zurich on the first High Repetition rate laser (HR1) is under way to investigate charge migration in liquid targets.

Most excitement yet to come
Though in 2018 the developments at the facility have accelerated exponentially, Osvay and his teams cannot and will not sit back and relax yet. ‘The next coming months will perhaps be the most exciting so far, since we are planning to finalize the installation of the remaining three lasers. Come back for an update next March, when hopefully I can tell you that all systems are running exactly as initially planned years ago.’