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Working Groups

Currently, 10 working groups are active at Helmholtz Institute Jena.


Theoretical and computational relativistic laser-plasma and X-ray generation physics

Contact: Dr. Sergey Rykovanov

The aim of our research group is to advance the theoretical understanding of the processes occurring in relativistic laser plasmas under extreme conditions. Our research program targets the study of effects such as particle acceleration, X- and gamma-ray generation, attosecond physics, and generation of electron-positron pairs and cascades. Besides being attractive for various applications, these topics are also of extreme importance for our understanding of the universe, particularly in the area of plasma astrophysics. We are also active in the development of novel numerical methods and codes for studying particle and plasma dynamics in extreme laser fields, using modern programming techniques and hardware architectures.


Quantum Field Theory at highest intensities

Contact: Prof. Dr. Holger Gies, Dr. Felix Karbstein
Homepage: Quantum Field Theory

Modern high-intensity laser systems are about to give access to fundamental physics phenomena. Complementary to particle accelerators, lasers have the potential to probe fundamental properties of nature on the microscopic quantum level. Our group explores this new potential on the theoretical basis of quantum field theory. Our goal is to identify and investigate new high-intensity phenomena and suggest concrete experimental set-ups for their verification.­


Relativistic quantum dynamics of ions and beams

Contact: Prof. Dr. Stephan Fritzsche, Dr. Andrey Volotka
Homepage: Relativistic Quantum Dynamics of Ions and Beams

The focus of our research work is placed upon the relativistic quantum dynamics of ions and beams. Our goal is to investigate the structure, properties and the dynamical behaviour of few- and multi-electron ions with emphasis on strong Coulomb and radiation fields as well as relativistic collision energies. We aim to better understand relativistic, many-body and quantum electrodynamical (QED) effects under – more or less – extreme conditions.

Our theoretical studies have impact also on a large number of other research areas, from astro- and nuclear physics to warm dense matter, plasma diagnostics and laser spectroscopy, and up to "new physics" beyond the standard model of particles and interactions.


Atomic physics with highly charged ions and X-rays

Contact: Prof. Dr. Thomas Stöhlker, Dr. Günter Weber
Homepage: Atomic Physics with Highly-Charged Ions

The current research program focus on the investigation of hard X-ray radiation from charged particle collisions or photon-matter  interactions.

Our special interest lies on the study of simple atomic systems in the widely unexplored domain of heavy high-Z ions in order to test and to advance our basic knowledge about the physics of strong fields. These investigations are complemented by the studies of processes which appear in high intense laser fields or at synchrotron facilities.

Within our experimental campaigns various X-ray detection systems such as standard X-ray detectors, 2D position-sensitive detectors, crystal spectrometers, X-ray CCDs and micro-calorimeters are used.


High Intensity Laser Physics

Set-up of an experiment for the efficient generation of soft X-ray radiation from a relativistically oscillating mirror.
Set-up of an experiment for the efficient generation of soft X-ray radiation from a relativistically oscillating mirror.

Contact: Prof. Dr. Matt Zepf

Physics has long been advanced by probing nature in extreme conditions, be it extremely low temperatures, extremely high particle energies or, as in our case, extremely high fields. Our group seeks to develop the underlying laser technology and apply it to scientific questions ranging from the fundamental behaviour of the quantum vacuum to laser driven particle accelerators and coherent soft X-ray sources.

Our research is conducted at our own cutting edge lasers – JETI and POLARIS – as well as external research facilities. We have an active programme developing advanced targets (cryogenic and thin foil), tailoring gas targets to elucidate the physics of laser driven electron accelerators as well as developing detectors for the specific needs of laser driven particle and photon sources.


Strong-field interaction with ionic targets

Contact: Prof. Dr. Gerhard G. Paulus
Homepage: Chair in Non-linear Optics

In this research project, a beam of atomic or molecular ions is overlapped with ultrashort laser fields that reach few femtoseconds, and intensities up to 1017 W/cm2. The momentum distribution of the resulting fragments from the laser-matter interaction is measured in all three dimensions. The experimental data is used to test existing theoretical models and inspire new ones. The parameter space offered by the combination of ionic targets and ultrashort laser fields approaching the relativistic regime is unique and thus enables the exploration.


Soft X-ray spectroscopy and microscopy

Contact: Dr. Jan Rothhardt
Homepage: Soft X-Ray Spectroscopy and Microscopy

The “soft X-ray spectroscopy and microscopy” group focuses on the development and applications of high photon flux XUV and soft x-ray sources. Such sources are enabled by high harmonic generation with high average power femtosecond fiber lasers. These unique table-top short-wavelength sources are employed for spectroscopy of highly-charged ions and nanoscale imaging.


High purity X-ray polarimetry and X-ray spectroscopy

Contact: Prof. em. Eckhart Förster, Dr. Ingo Uschmann
Homepage: X-Ray Optics

The topics of our group are the precise measurements of x-ray emission spectra and the precise determination of the polarization states of different x-ray sources such as highly excited matter (plasma, ions) and new x-ray sources such as synchrotrons of third generation and X-ray Free-Electron Lasers. In addition, we investigate methods for the detection of small polarization changes introduced by various samples like thin films or magnetic structures. In order to understand the physical processes observed by our techniques, we have developed highly sophisticated experimental and simulation methods to understand the detailed processes of our x-ray diagnostic systems. The applied methods are used in different fields of physics for instance in solid state physics, quantum electrodynamics, and plasma physics.


Relativistic laser physics

Contact: Prof. Dr. Malte Kaluza
Homepage: Relativistic Laser Physics

The research of the relativistic laser physics group is focused on the development and application of high-power laser systems reaching peak powers in excess of 100 TW. In our group, the laser system POLARIS has been developed. Currently, POLARIS is the only fully diode-pumped system producing 100-TW pulses, which are can be used for experiments. With such laser pulses, we investigate the acceleration of charged particles (electrons, protons or heavier ions) from laser-generated plasmas to energies of several 10’s or 100’s of MeV. The development of suitable diagnostics, most notably a few-cycle optical probe pulse, allows for detailed studies with unprecedented spatial and temporal resolution. Possible applications of the generated particle pulses, in particular the generation of ultra-short pulses of secondary electro-magnetic radiation or the application of laser-accelerated proton pulses for cell irradiation, are also investigated.


High photon flux sources from EUV to mid-IR

Contact: Prof. Dr. Jens Limpert
Homepage: www.iap.uni-jena.de

Most scientific and industrial applications ask for coherent laser sources in a variety of spectral regions with high repetition rate and high photon flux. To address this need we investigate new performance scaling approaches of ultrafast laser sources in the near infrared and their frequency conversion towards shorter wavelengths (UV, EUV and X-rays) as well as longer wavelengths towards the mid-infrared. As a result of these efforts the sources, which are developed in the group, are among the world's most powerful lasers.