This is the first high-resolution seismic study showing how the Chicxulub impact shaped the eastern slope of the Campeche Bank in the south-eastern Gulf of Mexico. The induced shock wave fractured Cretaceous strata causing the collapse of the upper slope and shelf over a length of ca. 200 km. Failed material was either transported downslope or remained in parts on the accommodation space created by the collapsed. In the Cenozoic, the East Campeche Plastered Drift developed within the created accommodation space, controlled by the inflowing surface current from the Caribbean, which forms the Loop Current. The internal reflection configuration of the drift shows that the closure of the Suwannee Strait in the Late Oligocene and the closure of the CAS in the Mid to Late Miocene controlled the variability of the southern Loop Current in time. Since the Loop Current transports heat and moisture from the western Atlantic warm water pool into the North Atlantic and further to NW Europe by the Gulf Stream, the drift represents an archive for controlling factors that influenced climate of the northern hemisphere. This first high-resolution seismic reflection study from the eastern Campeche Bank expands the understanding of destructive processes that a meteorite impact induces into the earth system. Furthermore, these data document that the East Campeche Plastered Drift bears the potential to understand the link between the climate variability of the northern hemisphere and oceanic processes in the equatorial western Atlantic.

In this work, a numerical modal decomposition approach is applied to model the optical field of laser light after propagating through a highly multi-mode fiber. The algorithm for the decomposition is based on the reconstruction of measured intensity profiles along the laser beam caustic with consideration of intermodal degrees of coherence derived from spectral analysis. To enhance the accuracy of the model, different approaches and strategies are applied and discussed. The presented decomposition into a set of LP modes enables both the wave-optical simulation of radiation transport by highly multi-mode fibers and, additionally, the analysis of free-space propagation with arbitrarily modified complex amplitude distributions.

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Detailed knowledge about the laser-material interaction, especially the distribution of laser power absorption, is a prerequisite for the simulation and optimization of laser material processing. In this work, an algorithm based on ray tracing is presented to calculate the propagation and the absorption of a laser beam inside a complex 3D cutting kerf. To model the laser beam precisely, a ray source based on high-power intensity measurements of the laser beam emitted from a highly multimode step-index fiber is set up. For the 3D reconstruction of the cutting kerf geometry, a semicircle model derived from three characteristic lines of so-called “frozen cuts” is applied. The presented approach enables a direct simulation of the laser absorption inside the cutting kerf considering light propagation properties like beam degeneration, shadowing effects, and multiple reflections. As a benchmark, it is finally applied to analyze cutting experiments in stainless steel with an axicon telescope.

Geometric optics is widely applied for diverse optical simulations. In this work, we introduce an incoherent ray model to describe the laser beam radiation emitted from a highly multi-mode step-index fiber, which is frequently applied for industrial laser material processing. First the mathematical validation and the limitation of this model are demonstrated. Then we determine the ray density and the angular spectrum according to measured intensity profiles along the caustic. Furthermore, based on the determined information, we demonstrate the simulation and measurement of the laser beam shaped by an axicon telescope. Not only the reconstruction itself, but also the simulation with free form optics present significant agreements to the measurements. The reasonable modeling of a laser source via geometric optics enables the precise determination of laser radiation and propagation properties with refractive beam shaping technologies.