Stand-off filament-induced ablation of gallium arsenide

Abstract

Using femtosecond filaments for the ablation of GaAs in air, we have observed that the diameter and volume of the resulting ablation craters remained almost constant with propagation distance. This constant mass removal along the propagation of a filament in both focused and non-focused configurations is valuable for applications such as material processing and stand-off laser-ablation based spectroscopy.

Remote isotope detection and quantification using femtosecond filament-laser ablation molecular isotopic spectrometry

“…Similar results were obtained with ablation of GaAs [23]. The estimated fluence was 5 J/cm 2 with 8 approximately 1.1 ng of removed material based on a Si 2.33 g/cm 3 density.…”

“…This ring is almost at the same height as the substrate, and is most likely attributed to localized lower fluence oxide formation. This is because the filament core and energy reservoir (where the majority of the filament energy is contained) are further surrounded by the less intense portion of the beam that contains the remaining energy [23]. Figure 3 shows optical microscopy images, demonstrating shot-to-shot ablation on the silicon surface.…”

Plasma temperature clamping in filamentation laser induced breakdown spectroscopy

“…The changes in signal intensity at various locations along the filament channel can be correlated to atomic number density, which is directly connected to ablation efficiency. Weidman et al [28] noticed the craters generated during filament assisted ablation are larger in diameter than the filament core (typically ~100 µm) and explained that the laser energy contained in the energy reservoir may also be used for ablation. Hence the ablation efficiency during filament assisted plasma generation depends both on clamped filamentation intensity and the rest of the energy distributed in the filament reservoir.…”

Standoff Detection of Uranium and its Isotopes by Femtosecond Filament Laser Ablation Molecular Isotopic Spectrometry

“…In this expression P cr is in the units of W. An interplay of plasma defocusing and nonlinear self-focusing results in generation and stable propagation of a laser filament with a typical intensity on the order of 10 13 W/cm 2 9 10 . A filament has a central core with diameter in the range of 100–200 mm, which is surrounded by an energy reservoir 9 11 12 . Filaments have been shown to be capable of propagating over distances on the order of kilometers 13 .…”

“…Filaments have been shown to be capable of propagating over distances on the order of kilometers 13 . The range of filament propagation is dependent on the initial laser pulse parameters 14 and on the characteristics of the external focusing 12 . Further, the characteristics of filament-induced plasma, including its optical emission, are dependent on the filament spatial evolution 15 .…”