“…In earlier fs-DP-LIBS experiments using oblique incidence of the second pulse, we also observed an intensity enhancement. 42 However, the second pulse was interacting with the sample and the intensity enhancement was due to an increased number of atoms in plasma (larger crater volume) and a higher plasma temperature. In the present study, the orthogonal beam arrangement did not increase the crater sizes and the enhancement was probably due to the reheating of the LIP.Figure 7.(a) Fs-LIBS spectra of glass measured by single-pulse (520 nm), enhancement pulse (1040 nm), and double-pulse (520 nm + 1040 nm) excitation.…”
Section: Resultsmentioning
confidence: 99%
“…The physical properties of laser-induced plasma (LIP) such as temperature and electron number density and their dependence on interpulse delay have been studied. [40][41][42] The intensity enhancement has been found to depend on many experimental parameters such as laser wavelength, pulse energies and duration, and the geometrical arrangement of the two laser beams, i.e., collinear and orthogonal beam geometry. 43 Lately, the DP-LIBS technique has been applied using fs-pulses in the collinear beam configuration and an enhancement of line intensities has been observed.…”
Femtosecond laser-induced breakdown spectroscopy (fs-LIBS) is employed to detect tiny amounts of mass ablated from macroscopic specimens and to measure chemical images of microstructured samples with high spatial resolution. Frequency-doubled fs-pulses (length 400 fs, wavelength 520 nm) are tightly focused with a Schwarzschild microscope objective to ablate the sample surface. The optical emission of laser-induced plasma (LIP) is collected by the objective and measured with an echelle spectrometer equipped with an intensified charge-coupled device camera. A second fs-laser pulse (1040 nm) in orthogonal beam arrangement is reheating the LIP. The optimization of the experimental setup and measurement parameters enables us to record single-pulse fs-LIBS spectra of 5 nm thin metal layers with an ablated mass per pulse of 100 femtogram (fg) for Cu and 370 fg for Ag films. The orthogonal double-pulse fs-LIBS enhances the recorded emission line intensities (two to three times) and improves the contrast of chemical images in comparison to single-pulse measurements. The size of ablation craters (diameters as small as 1.5 µm) is not increased by the second laser pulse. The combination of minimally invasive sampling by a tightly focused low-energy fs-pulse and of strong enhancement of plasma emission by an orthogonal high-energy fs-pulse appears promising for future LIBS chemical imaging with high spatial resolution and with high spectrochemical sensitivity.
“…In earlier fs-DP-LIBS experiments using oblique incidence of the second pulse, we also observed an intensity enhancement. 42 However, the second pulse was interacting with the sample and the intensity enhancement was due to an increased number of atoms in plasma (larger crater volume) and a higher plasma temperature. In the present study, the orthogonal beam arrangement did not increase the crater sizes and the enhancement was probably due to the reheating of the LIP.Figure 7.(a) Fs-LIBS spectra of glass measured by single-pulse (520 nm), enhancement pulse (1040 nm), and double-pulse (520 nm + 1040 nm) excitation.…”
Section: Resultsmentioning
confidence: 99%
“…The physical properties of laser-induced plasma (LIP) such as temperature and electron number density and their dependence on interpulse delay have been studied. [40][41][42] The intensity enhancement has been found to depend on many experimental parameters such as laser wavelength, pulse energies and duration, and the geometrical arrangement of the two laser beams, i.e., collinear and orthogonal beam geometry. 43 Lately, the DP-LIBS technique has been applied using fs-pulses in the collinear beam configuration and an enhancement of line intensities has been observed.…”
Femtosecond laser-induced breakdown spectroscopy (fs-LIBS) is employed to detect tiny amounts of mass ablated from macroscopic specimens and to measure chemical images of microstructured samples with high spatial resolution. Frequency-doubled fs-pulses (length 400 fs, wavelength 520 nm) are tightly focused with a Schwarzschild microscope objective to ablate the sample surface. The optical emission of laser-induced plasma (LIP) is collected by the objective and measured with an echelle spectrometer equipped with an intensified charge-coupled device camera. A second fs-laser pulse (1040 nm) in orthogonal beam arrangement is reheating the LIP. The optimization of the experimental setup and measurement parameters enables us to record single-pulse fs-LIBS spectra of 5 nm thin metal layers with an ablated mass per pulse of 100 femtogram (fg) for Cu and 370 fg for Ag films. The orthogonal double-pulse fs-LIBS enhances the recorded emission line intensities (two to three times) and improves the contrast of chemical images in comparison to single-pulse measurements. The size of ablation craters (diameters as small as 1.5 µm) is not increased by the second laser pulse. The combination of minimally invasive sampling by a tightly focused low-energy fs-pulse and of strong enhancement of plasma emission by an orthogonal high-energy fs-pulse appears promising for future LIBS chemical imaging with high spatial resolution and with high spectrochemical sensitivity.
“…Another research field where MSE Stark broadening data are needed is laser-induced breakdown spectroscopy (LIBS), a type of atomic emission spectroscopy where a highly energetic laser pulse is focused to form a plasma, which atomizes and excites samples. Examples of articles where MSE Stark broadening data have been used and cited are on LIBS using mid-infrared femtosecond pulses [107], fiber-optic LIBS of zirconium metal in air [97], investigation of self-absorption of Mn emission lines in LIBS measurements [98], optimization of the temporal window for employment of calibration free-LIBS on Cu alloys in air using a single line study [117], investigation of the matrix effect on the plasma characterization of heavy elements in soil sediments with LIBS and a portable echelle spectrometer [102], femtosecond double pulse LIBS-investigation of intensity enhancement [113], calibration-free analysis of immersed metal alloys with long-pulse-duration LIBS [115], and influence of correction for self-absorption on LIBS measurements using a calibration curve and an artificial neural network [120].…”
Section: Lasers and Laser Produced Plasmamentioning
The aim of this paper is to analyze the various uses of Stark broadening data for non-hydrogenic lines emitted from plasma, obtained with the modified semiempirical method formulated 40 years ago (1980), which are continuously implemented in the STARK-B database. In such a way one can identify research fields where they are applied and better see the needs of users in order to better plan future work. This is done by analysis of citations of the modified semiempirical method and the corresponding data in international scientific journals, excluding cases when they are used for comparison with other experimental or theoretical Stark broadening data or for development of the theory of Stark broadening. On the basis of our analysis, one can conclude that the principal applications of such data are in astronomy (white dwarfs, A and B stars, and opacity), investigations of laser produced plasmas, laser design and optimization and their applications in industry and technology (ablation, laser melting, deposition, plasma during electrolytic oxidation, laser micro sintering), as well as for the determination of radiative properties of various plasmas, plasma diagnostics, and investigations of regularities and systematic trends of Stark broadening parameters.
Composition analysis of LiF-C thin film for neutral and ionic contributions in Front Ablation (FA) and Back Ablation (BA) geometries in vacuum and 2 × 10 −1 mbar argon has been done. Temporal evolution of ionic to neutral ratio and neutral abundance for both the geometries has been estimated. For neutral abundance, two approaches viz Atomic Data and Analysis Structure (ADAS) analysis as well as integrated intensity ratio of Li I 670.1 nm and Li I 610.3 nm lines assuming LTE conditions are explored. The present attempt will be interesting from the view point of understanding the evolution of plasma composition in various geometries/configurations of laser ablation which has important implications in various applications e.g. pulsed laser deposition and laser cleaning.
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