arXiv subjects

Sascha Schnepp

Publications and source records attributed to Sascha Schnepp.

2 recordsLinked to original sources

arXiv2014

Temporal and spectral disentanglement of laser-driven electron tunneling emission from a solid

By measuring energy spectra of the electron emission from a sharp tungsten tip induced by few-cycle laser pulses, the laser-field dependence of the emission mechanism was investigated. In strong laser fields, we confirm the appearance of laser-driven tunneling emission and find that it can be disentangled from the concomitant photo-excited electron emission, both temporally and spectrally, by the opening of a peculiar emission channel. This channel involves prompt laser-driven tunneling emission and subsequent laser-driven electron re-scattering off the surface, delayed by the electrons traveling far inside the metal before scattering. The quantitative understanding of these processes gives insights on attosecond tunneling emission from solids and should prove useful in designing new types of pulsed electron sources.

cond-mat.mes-hall↗

arXiv2013

Discontinuous Galerkin Methods with Trefftz Approximation

We present a novel Discontinuous Galerkin Finite Element Method for wave propagation problems. The method employs space-time Trefftz-type basis functions that satisfy the underlying partial differential equations and the respective interface boundary conditions exactly in an element-wise fashion. The basis functions can be of arbitrary high order, and we demonstrate spectral convergence in the $\Lebesgue_2$-norm. In this context, spectral convergence is obtained with respect to the approximation error in the entire space-time domain of interest, i.e. in space and time simultaneously. Formulating the approximation in terms of a space-time Trefftz basis makes high order time integration an inherent property of the method and clearly sets it apart from methods, that employ a high order approximation in space only.

physics.comp-ph↗