Energy penetrated and inverse bremsstrahlung absorption co-efficient in laser ablated germanium plasma

Ashraf, Muhammad; Shaikh, Nek M.; Kandhro, Ghulam Abbas; Murtaza, Ghulam; Iqbal, Javed; Iqbal, Azhar; Lashari, Shafqat Ali

doi:10.1016/j.molstruc.2019.127412

Cited by 8 publications

(5 citation statements)

References 36 publications

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“…During the topcoat + primer stage, the energy density of the laser is higher than that of the topcoat stage. During continuous laser operation, plasma absorbs the energy of the laser beam propagating through it through various mechanisms, such as inverse bremsstrahlung absorption, 26 leading to an increase in temperature and ionization, thereby enhancing the plasma signal. Additionally, due to the lower laser reflectivity of the green primer layer compared to the white topcoat, the material accumulates absorbed energy, leading to possible heating effects and sample preheating, 27 further enhancing the plasma signal.…”

Section: Resultsmentioning

confidence: 99%

Research on online monitoring of aircraft skin laser paint removal thickness using standard curve method and PCA-SVR based on LIBS

Yang,

Li,

Qian

et al. 2024

Anal. Methods

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Section: Resultsmentioning

confidence: 99%

Research on online monitoring of aircraft skin laser paint removal thickness using standard curve method and PCA-SVR based on LIBS

Yang,

Li,

Qian

et al. 2024

Anal. Methods

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“…For shorter wavelengths, the photoionization process is dominant and for higher wavelengths, Inverse Bremsstrahlung ionization (IB) is more dominant. 40 The plasma parameters depend upon IB and its general form 25–40 can be written as:in which λ(μm) is the laser wavelength on which IB depends. In this work, the fundamental harmonic Nd:YAG laser of wavelength 1064 nm is used so that Inverse Bremsstrahlung is more dominant than the photoionization process.…”

Section: Characterization Of Kohl Plasmamentioning

confidence: 99%

Section: Electron Number Density (N E )mentioning

confidence: 99%

Magnetic-Field-Confined Laser Induced Kohl Plasma: Elemental Analysis and Plasma Characterization

et al. 2023

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In this study, the laser-induced kohl plasma is produced in the vicinity of the transverse magnetic field (B) of 0.8 Tesla. The Q-switched Nd: YAG laser (, λ = 1064 nm, E = 100 mJ, τl = 8 ns) is focused to produce the kohl plasma with and without a B-field, and the plasma emissions are recorded using a LIBS spectrometer. The comparison of the emission spectra shows that most of the emission line intensities are reduced due to the field. However, except for a few lines which are enhanced up to 3 times. However, the Plasma Parameters such as electron temperature (Te), electron number density (Ne), and plasma frequency (ʋp) have been increased. Furthermore, thermal beta (βt) is also estimated analytically, and its value is smaller than one (β < 1) for all samples, which confirmed the evidence of magnetic confinement effects. According to the analysis of the kohl emission spectrum, several elements are detected (Pb, Ca, Mg, Fe, Cr, Zn), among which lead (Pb) and chromium (Cr) may cause chronic health effects like contact dermatitis and neurological diseases. A calibration-free LIBS (CF-LIBS) method is used for the quantitative elemental analysis of the detected elements, which yields Pb as 15-74% and Cr as 3%, which exceed the permissible limit for kohl.

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“…However, multi-photon energy absorption leads to bond breaking and produces a large number of atoms, which are ionized by photons and continue to produce ions. The composite transfer of electrons and ions makes ultimate energy exceed 3.71 eV, a process also known as the multi-photon effect [36]. Thus, acrylic polyurethane molecules are in a state of dissociation as C-O chemical bonds are broken.…”

Section: Effect Of Anodic Oxide Films On Surface Qualitymentioning

confidence: 99%

Multi-Perspective Evaluations of Laser-Removal Quality of Acrylic Polyurethane Coatings on Aluminum Alloy Substrate

Huang

Shen

et al. 2023

Coatings

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Evaluation systems for objects after laser removal have not been systematically established, yet they have great significance for repairing engineering coating materials. In general, this paper mainly focused on the surface quality after laser removal, which was simulated by thermal models and characterized by microscopic, residual chemical compositions, and wettability. The laser removal threshold was considered to be a key indicator to regulate removal precision. Here, the thermal model was used to explore the threshold was 15 J/cm2, and the ablation P was 308 W at 100 kHz. Besides, the surface structure was observed through simulation before experiments. It also predicted the effect of laser power and overlapping on surface roughness, and therefore provided the theoretical reference for experiments. Then, two groups of samples were set up of the surface of acrylic polyurethane coatings on 2024 aluminum alloy with and without anodizing treatment, respectively. After the coatings were removed, microscopic morphologies demonstrated a wavy undulation structure with little residue. Meanwhile, the increments of roughness were less than 0.5 μm and the surfaces were with nice wettability. Evaluating the surface quality from the above aspects is meaningful and helpful for the non-destructive cleaning of aircraft skin coatings.

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Energy penetrated and inverse bremsstrahlung absorption co-efficient in laser ablated germanium plasma

Cited by 8 publications

References 36 publications

Research on online monitoring of aircraft skin laser paint removal thickness using standard curve method and PCA-SVR based on LIBS

Research on online monitoring of aircraft skin laser paint removal thickness using standard curve method and PCA-SVR based on LIBS

Magnetic-Field-Confined Laser Induced Kohl Plasma: Elemental Analysis and Plasma Characterization

Multi-Perspective Evaluations of Laser-Removal Quality of Acrylic Polyurethane Coatings on Aluminum Alloy Substrate

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