Publications de Christoph Bostedt

SPRING, an effective and reliable framework for image reconstruction in single-particle Coherent Diffraction Imaging

Coherent Diffraction Imaging (CDI) is an experimental technique to image isolated structures by recording the scattered light. The sample density can be recovered from the scattered field through a Fourier Transform operation. However, the phase of the fie ...

2025

Non-linear enhancement of ultrafast X-ray diffraction through transient resonances

Christoph Bostedt

Diffraction-before-destruction imaging with ultrashort X-ray pulses can visualize non-equilibrium processes, such as chemical reactions, with sub-femtosecond precision in the native environment. Here, a nanospecimen diffracts a single X-ray flash before it ...

NATURE PORTFOLIO2025

Ultrathin liquid sheets: water gets in shape for VUV absorption

Christoph Bostedt

We present absorption spectra of thin, free-flowing liquid sheets in the vacuum ultraviolet energy range using a gas-squeezed liquid jet. Compared to liquid flow cells, operation without transmission windows eliminates restrictions on the energy range. The ...

ROYAL SOC CHEMISTRY2025

Demonstration of full polarization control of soft X-ray pulses with Apple X undulators at SwissFEL using recoil ion momentum spectroscopy

Iwona Swiderska, Christoph Bostedt, Jonas Knurr

The ability to freely control the polarization of X-rays enables measurement techniques relying on circular or linear dichroism, which have become indispensable tools for characterizing the properties of chiral molecules or magnetic structures. Therefore, ...

INT UNION CRYSTALLOGRAPHY2024

Experimental demonstration of attosecond pump-probe spectroscopy with an X-ray free-electron laser

Jun Wang, Christoph Bostedt, Siqi Li, Zhen Zhang, Zhaoheng Guo, Xiang Li

Pump-probe experiments with subfemtosecond resolution are the key to understanding electronic dynamics in quantum systems. Here we demonstrate the generation and control of subfemtosecond pulse pairs from a two-colour X-ray free-electron laser. By measurin ...

Nature Publishing Group2024

Attosecond delays in X-ray molecular ionization

Christoph Bostedt

The photoelectric effect is not truly instantaneous but exhibits attosecond delays that can reveal complex molecular dynamics(1-7). Sub-femtosecond-duration light pulses provide the requisite tools to resolve the dynamics of photoionization(8-12). Accordin ...

NATURE PORTFOLIO2024

Double diffraction imaging of x-ray induced structural dynamics in single free nanoparticles

Christoph Bostedt

Because of their high photon flux, x-ray free-electron lasers (FEL) allow to resolve the structure of individual nanoparticles via coherent diffractive imaging (CDI) within a single x-ray pulse. Since the inevitable rapid destruction of the sample limits t ...

IOP Publishing Ltd2024

A multi-reservoir extruder for time-resolved serial protein crystallography and compound screening at X-ray free-electron lasers

Camila Bacellar Cases Da Silveira, Christoph Bostedt

Serial crystallography at X-ray free-electron lasers (XFELs) permits the determination of radiation-damage free static as well as time-resolved protein structures at room temperature. Efficient sample delivery is a key factor for such experiments. Here, we ...

Nature Portfolio2023

Data for "Ultrafast deep-ultraviolet study of photoexcited aqueous Ferrioxalate"

Majed Chergui, Malte Oppermann, Michele Puppin, Christoph Bostedt, Hui-Yuan Chen

Data repository for the following publication: A. Duque-Prata*, H.-Y. Chen*, L. Müller, M. Oppermann, M. Puppin, C. Serpa, C. Bostedt and M. Chergui, “Ultrafast deep-ultraviolet study of photoexcited aqueous Ferrioxalate”, submitted to ChemPhotoCh ...

Zenodo2023

An X-ray free-electron laser with a highly configurable undulator and integrated chicanes for tailored pulse properties

Christoph Bostedt

Since their initial operation, free-electron lasers are regularly upgraded in their performance and parameter control. Here the authors present the first lasing results of the soft X-ray free-electron laser beamline of the Paul Scherrer Institute, demonstr ...

Nature Portfolio2023

Few-femtosecond resolved imaging of laser-driven nanoplasma expansion

Matthias Bucher, Christoph Bostedt

The free expansion of a planar plasma surface is a fundamental non-equilibrium process relevant for various fields but as-yet experimentally still difficult to capture. The significance of the associated spatiotemporal plasma motion ranges from astrophysic ...

IOP Publishing Ltd2022

Ultrafast Single-particle Imaging with Intense X-ray Pulses

Christoph Bostedt

Ultrafast single-particle imaging with intense x-ray pulses from free-electron laser sources provides a new approach for visualizing structure and dynamics on the nanoscale. After a short introduction to the novel free-electron laser sources and methods, w ...

SWISS CHEMICAL SOC2022

Sizes of pure and doped helium droplets from single shot x-ray imaging

Christoph Bostedt

Advancements in x-ray free-electron lasers on producing ultrashort, ultrabright, and coherent x-ray pulses enable single-shot imaging of fragile nanostructures, such as superfluid helium droplets. This imaging technique gives unique access to the sizes and ...

AIP Publishing2022

Observation of site-selective chemical bond changes via ultrafast chemical shifts

Solène Oberli, Christoph Bostedt

X-ray photoelectron spectroscopy probes the chemical environment in a molecule at a specific atomic site. Here the authors extend this concept with a site selective trigger to follow chemical bond changes as they occur on the femtosecond time scale. ...

Nature Portfolio2022

Attosecond coherent electron motion in Auger-Meitner decay

Christoph Bostedt

In quantum systems, coherent superpositions of electronic states evolve on ultrafast time scales (few femtoseconds to attoseconds; 1 attosecond = 0.001 femtoseconds = 10(-18) seconds), leading to a time-dependent charge density. Here we performed time-reso ...

American Association for the Advancement of Science2022

Widely tunable two-color x-ray free-electron laser pulses

Christoph Bostedt, Jonas Knurr

We demonstrate the generation of widely tunable two-color x-ray free-electron laser (FEL) pulses at Swiss-FEL. In a split-undulator configuration, each color is produced in a different undulator section, and a chicane between the two sections allows for a ...

AMER PHYSICAL SOC2022

Aggregation of solutes in bosonic versus fermionic quantum fluids

Christoph Bostedt

Quantum fluid droplets made of helium-3 (He-3) or helium-4 (He-4) isotopes have long been considered as ideal cryogenic nanolabs, enabling unique ultracold chemistry and spectroscopy applications. The droplets were believed to provide a homogeneous environ ...

AMER ASSOC ADVANCEMENT SCIENCE2021

Correlation-Driven Transient Hole Dynamics Resolved in Space and Time in the Isopropanol Molecule

Andrew Daniel Bonnar Clark, Christoph Bostedt

The possibility of suddenly ionized molecules undergoing extremely fast electron hole (or hole) dynamics prior to significant structural change was first recognized more than 20 years ago and termed charge migration. The accurate probing of ultrafast elect ...

American Physical Society2021

Clocking Auger electrons

Christoph Bostedt

Intense X-ray free-electron lasers (XFELs) can rapidly excite matter, leaving it in inherently unstable states that decay on femtosecond timescales. The relaxation occurs primarily via Auger emission, so excited-state observations are constrained by Auger ...

2021

Two-dimensional correlation analysis for x-ray photoelectron spectroscopy

Andre Al Haddad, Thomas Roland Barillot, Christoph Bostedt

X-ray photoelectron spectroscopy (XPS) measures the binding energy of core-level electrons, which are well-localised to specific atomic sites in a molecular system, providing valuable information on the local chemical environment. The technique relies on m ...

IOP Publishing2021