Quantum Electronics

Prof. Dr. Christian SPIELMANN

Email: christian.spielmann@uni-jena.de
Phone: +49 3641-9-47230

Prof. Christian Spielmann holds the Chair of Quantum Electronics at the Institute of Optics and Quantum Electronics of Friedrich Schiller University Jena and is Co-Director of the Abbe Center of Photonics.

His research focuses on ultrafast and strong-field optics from the infrared to the extreme-ultraviolet and x-ray spectral regions. Particular emphasis lies on high-order harmonic generation, coherent XUV sources, ultrafast spectroscopy, nanoscale imaging and laser-plasma-based short-wavelength radiation.

Research Areas

Prof. Spielmann's research of is focused on the generation and application of ultra-short pulses from the infrared to the x-ray regions, including:

High-order harmonic generation in gases, solids and nanostructures
Coherent XUV and soft-x-ray sources
Ultrafast and strong-field light–matter interaction
Nonlinear optics in solids and nanostructured materials
Coherent diffraction imaging and lensless XUV microscopy
XUV ghost imaging and computational imaging
Time-resolved XUV and x-ray spectroscopy
Laser-plasma-based x-ray and particle sources

Teaching Fields

Prof. Spielmann's lectures center on:

Atomic and molecular physics
Fundamentals of modern photonics
XUV and x-ray optics
Modern methods of spectroscopy

Research Methods

The equipment of Prof. Spielmann’s laboratories allows for studying the structural dynamics of atomic and solid systems as well as imaging nanostructures:

Generation and characterization of ultrashort laser pulses
Spatial and temporal pulse shaping
Tunable near- and mid-infrared femtosecond sources
High-order harmonic generation
Coherent XUV and soft-x-ray spectroscopy
Coherent diffraction imaging and ptychography
Computational and ghost imaging
Laser-plasma x-ray diagnostics
Time-resolved spectroscopy of solids and nanostructures

Nonlinear ionization dynamics in hot dense plasma observed in a laser-plasma amplifier.
Image: Published by the Spielmann research group.

Recent Research Results

High-order harmonic generation provides compact coherent radiation in the extreme-ultraviolet spectral range and remains a central research topic of the group. Recent work has extended HHG towards solid-state and nanophotonic systems. Measurements on monolayer semiconductors revealed the influence of multiband electronic structure on the emitted harmonics, while phase-change nanofilms have enabled tunable high-harmonic emission controlled through material state and nanostructure design [1,2].

A second major direction is coherent and computational XUV imaging. Building on tabletop short-wavelength sources, the group develops lensless imaging concepts that exploit coherent diffraction and ghost-imaging techniques. Recent work has improved microscopic ghost imaging through optimized speckle illumination and computational reconstruction, including deep-learning-assisted image recovery [3]. The group is currently extending these concepts towards the XUV spectral range. First experiments with tabletop XUV ghost imaging combine short-wavelength illumination with computational reconstruction and aim at high-resolution imaging with reduced radiation dose and simplified detection geometries [4].

Complementary research addresses laser-plasma-based short-wavelength sources and strong-field interaction with structured targets, providing intense x-ray and particle emission for ultrafast diagnostics and high-energy-density physics [5].

[1] Yue et al., Phys. Rev. Lett. 129, 147401 (2022).
[2] Korolev et al., Nanophotonics 13, 3411 (2024).
[3] Oh et al., Adv. Opt. Technol. 14, 1583836 (2025).
[4] Oh et al., Optica Laser Congress, JW2A.3 (2025).
[5] Gyrdymov et al., Sci. Rep. 14, 14785 (2024).

Link to the Quantum Electronics Group