Johannes Heberle | Searcharxiv

arXiv2025

Material processing by laser-plasma-filament-guided high voltage discharges

We investigate ablation experiments performed by laser-plasma-filament guided electrical discharges at high-voltages of up to 145 kV. The guiding was accomplished via fs-laser-generated plasma filaments across a gap of 201 mm of air onto steel 1.3343 samples. This method combines remote material processing and enables the steering and deflection of high voltage discharges with the ease-of-use of remote laser processing technology. We observe an increase of the per-pulse-(and-discharge)-ablated volume by a factor of 1.67 over an ablation regime when the discharges are not present and up to a factor of 12.5 over the case when neither discharges nor plasma filaments, only a loosely focused laser beam, are present.

physics.plasm-ph↗

arXiv2017

Four-dimensional light shaping: manipulating ultrafast spatio-temporal foci in space and time

Spectral dispersion of ultrashort pulses allows simultaneous focusing of light in both space and time creating so-called spatio-temporal foci. Such space-time coupling may be combined with existing holographic techniques to give a further dimension of control when generating focal light fields. It is shown that a phase-only hologram placed in the pupil plane of an objective and illuminated by a spatially chirped ultrashort pulse can be used to generate three dimensional arrays of spatio-temporally focused spots. Exploiting the pulse front tilt generated at focus when applying simultaneous spatial and temporal focusing (SSTF), it is possible to overlap neighbouring foci in time to create a smooth intensity distribution. The resulting light field displays a high level of axial confinement, with experimental demonstrations given through two-photon microscopy and non-linear laser fabrication of glass.

physics.optics↗