Conference Agenda

With the recent developments in Ultrafast Transmission Electron Microscopes (UTEM), new opportunities have emerged to overcome the limitations of conventional Transmission Electron Microscopes (TEM). Combined with optical pump-electron probe experiments, one can control

the phase of an electron beam through an inelastic (Photon-Induced Near field Electron Microscopy) or elastic (Ponderomotive) interaction. From these technics, one can correct the aberrations or generate arbitrary electron beams.

We propose a single-shot ultrafast imaging method that is both user-friendly and high-performance. It leverages the capabilities of two prominent technologies: acousto-optical pulse shaping and light-field-based hyperspectral imaging. We demonstrate its capabilities by capturing laser-induced phenomena at Tera-fps frame rates, with the potential to achieve even higher imaging speeds. The versatile setup can be easily adapted to various input pulse shapes and objects of interest. Furthermore, digital inline holography is used to add an extra degree of freedom to the system when capturing single-shot motion pictures.

The formation of photoelectron holograms of hydrogen atoms is investigated in a pump-drive setup. The continuum wave packet created by an attosecond pulse is streaked by an infrared field. In previous work by Borbély et al. [Phys. Rev. A 113, 013107 (2026)], an optimal pump-drive delay was identified for generating clean spatial interference patterns. Here, we extend the study by analyzing how the optimal delay depends on the carrier-envelope phase of the driving pulse. Based on the numerical solution of the time-dependent Schrödinger equation, we study how the carrier-envelope phase influences the optimal delay that maximizes the holographic signal. These results demonstrate that the carrier-envelope phase acts as an additional control parameter for optimizing photoelectron holography.

Ultrafast transient grating spectroscopy (TG) is a powerful

technique to investigate the dynamics and transport of charge carriers,

phonons, and spins in materials. In conventional TG implementations, the

grating pitch is typically defined by a phase mask that is imaged onto the

sample, limiting the accessible wave-vectors to discrete values determined

by the mask periodicity. In this work, we present a TG setup with a

continuously tuneable grating pitch based on a reconfigurable geometry. In

our scheme, the phase mask is used as a beamsplitter, while the grating pitch

is defined by the crossing angle between the beams. This angle is controlled

using mirrors mounted on translation stages, enabling flexible access to

different excitation wave-vectors with just one phase mask. We demonstrate

stable operation of the setup through time-resolved TG measurements on a

crystalline Ge sample, showing an ultrafast response followed by coherent

phonon oscillations corresponding to Rayleigh surface acoustic wave and

surface skimming longitudinal wave. The design provides a pathway

towards sub-micron grating pitches and a versatile platform for studying

transport phenomena at reduced length scales.

Smith-Purcell Radiation is generated when free electrons propagate above the surface of a periodic structure. By using an ultrafast laser to knock electrons out of a thin wire, we observe that a positively charged surface-plasmon-polariton pulse, or a hole pulse, propagating atop a metal grating can surprisingly generate radiation similar to the Smith-Purcell radiation produced by an electron pulse moving at the same speed.