Research Associate / Postdoc (d/m/w) with a focus on ultrafast pulse laser physics/optical frequency combs (Physicist)

Facility for Antiproton and Ion Research

Helmholtzzentrum für Schwerionenforschung GmbH

The Helmholtz-Institut Jena is a joint institution of the Friedrich-Schiller-Universität Jena and the GSI Helmholtzzentrum für Schwerionenforschung GmbH in Darmstadt. The institute's main research focus lies in fundamental and applied research using high-performance lasers and particle accelerator facilities.

For the "Ultrafast Photonics" research group, we are looking for a

Research Associate / Postdoc (d/m/w) with a focus on ultrafast pulse laser physics/optical frequency combs

Reference number: 26.127-4210

Nuclear spectroscopy of 229Thorium is a highly interesting research field in nuclear and atomic physics, dealing with the properties of an exceptionally low excited state in the nucleus of 229Thorium. This state has an estimated excitation energy of only about 8 eV. Only recently, it was possible for the first time to excite this state directly with an optical laser. Within the framework of the project HiTHOR, which is based at the Helmholtz-Institut Jena and funded by the European Research Council ERC, this nuclear transition is to be investigated in detail, promising unique new insights into the quantum physics of atomic nuclei as well as new approaches for building a high-precision "nuclear clock".

As part of this project, the further development of a frequency comb laser in the Vacuum-Ultraviolet (VUV) spectral range is intended. In contrast to existing VUV comb systems, a new, significantly more efficient approach is to be pursued. Another focus of this work is the development of a suitable control system as well as adjustments for the planned 229Thorium ion spectroscopy at GSI. The successful candidate will also support the supervision of a corresponding doctoral project.

We are looking for a person with

• a completed university degree and doctorate in physics, electrical engineering, or a related field,
• excellent experience and expertise in the field of laser stabilization, frequency combs, and phase-locked loops, demonstrated by relevant publications,
• experience in the field of fiber laser development and nonlinear optics,
• preferably existing knowledge in electronics, Python, and FPGA (VHDL) programming,
• interest in collaborating with experts in an inter-institutional cooperation project,
• very good written and spoken English skills,
• and strong teamwork skills.

We offer

A varied activity in an internationally renowned research institution, embedded in the Helmholtz-Gemeinschaft Deutscher Forschungszentren, the largest German organization for the promotion and funding of science. The position is initially limited to three years. The salary is based on the TVöD (Bund) collective agreement. The place of work is the Helmholtzzentrum DESY in Hamburg.

GSI promotes the professional development of women and welcomes applications from women who feel particularly addressed by this advertisement. Severely disabled persons will be given preference if they have equal qualifications.

Further information about the Helmholtz-Institut Jena, GSI and FAIR can be found at www.hi-jena.de, www.gsi.de (http://www.gsi.de) and www.fair-center.eu (http://www.fair-center.eu).

For further information, Prof. Dr. Thomas Stöhlker (t.stoehlker@hi-jena.gsi.de (https://mailto:[t.stoehlker@hi-jena.gsi.de](mailto:t.stoehlker@hi-jena.gsi.de)), Tel. +49 3641 9-47600) is at your disposal.

If you view the described field of activity as a personal challenge and are interested in working in an extraordinary personal environment, please send your complete application documents including your salary expectations, stating your earliest possible starting date and quoting the reference number 26-127-4210, no later than 09.10.2026.

via our online portal (https://www.gsi.de/jobskarriere/stellenangebote/online-bewerbung)

GSI Helmholtzzentrum für Schwerionenforschung GmbH Abteilung Personal Planckstrasse 1 64291 Darmstadt