Dependence of radiation decay constant of laser produced copper plasma on focal position

Junjuri, Rajendhar; Rashkovskiy, Sergey A.; Gundawar, Manoj Kumar

doi:10.1063/1.5118289

Cited by 12 publications

(18 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the prefocused case (H < 150 mm), as the H increased, the coupling efficiency between the laser pulse and the sample is increased firstly due to the reduced spot size, resulting in a stronger spectrum and an opaque plasma with higher density. Once the plasma density reaches a critical value, a thin layer forming above the target surface will absorb the subsequent energy and prevent the laser from propagating to the target, which is the phenomenon of plasma shielding [26]. Referring to the related report on laser-material interaction [27], the pulse duration of 120 ps is sufficient to maintain the target plasma encounters the rest incident energy.…”

Section: Resultsmentioning

confidence: 99%

Role of Focusing Distance in Picosecond Laser-Induced Cu Plasma Spectra

Chen

Deng

et al. 2022

Advances in High Energy Physics

View full text Add to dashboard Cite

To study the effects of focusing distance on the characteristics of copper plasma, a picosecond laser is utilized to ablate a pure copper plate to generate a plasma spectrum. Following numerous experiments on the subject, three significant factors are determined: lens focal length, pulse energy, and the lens-to-sample distance. These factors are employed to analyze the spectral intensity, plasma temperature, and electron density in the local thermodynamic equilibrium (LTE) and optically thin condition. Due to the shielding effects of mixed plasma, the strongest spectral intensity is achieved in the prefocused case, no matter how much beam irradiance is employed. The more intensive the beam irradiance is, the more the optimal position is distant from the focal point. The variation of plasma temperature and electron density showed a peak in the prefocused case, which is consistent with the trend of spectral intensity. For the case of extremely high irradiance (on the focus), the shielding effects become seriously, and the resultant above three factors decreased sharply. When a longer-focal-length lens is employed, the spectral intensity exhibited an obvious bimodal trend. In the prefocused case, a longer-focal-length lens is helpful to eliminate the effects of the roughness of the target surface compared with a shorter one. Finally, the assumed LTE is validated by McWhirter relation, plasma relaxation time, and diffusion length, and the optically thin condition was also validated by spectral intensity ratio. We hope that this work could be an important reference for the future design of highly optimized experiments for Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS).

show abstract

Section: Resultsmentioning

confidence: 99%

Role of Focusing Distance in Picosecond Laser-Induced Cu Plasma Spectra

Chen

Deng

et al. 2022

Advances in High Energy Physics

View full text Add to dashboard Cite

show abstract

“…Of particular interest were data on Stark broadening of Cu II lines [87]. They were used in articles considering dependence of laser fluence on dynamics of emission of copper plasma induced by ultrafast laser [109], the effect of uniform magnetic field on it and the particles deposited on the surface of target [110], studies of time-integrated optical emission for Cu plasma in air at atmospheric pressure with magnetic field [112], radiation decay constant dependence on focal position for copper plasma [116], the effect of hyperfine structure on Stark broadening in the case of three blue-green Cu spectral lines in plasma induced by laser [118], enhancement of signal intensity using cavity confinement of plasma produced by a laser [114], the study of temporal evolution of plasma induced by CO 2 pulsed laser on targets made of titanium oxides [99], the mechanism of effect of distance between a lens and a sample on plasma induced by laser [100], and the effect of ambient pressure on titanium plasma induced by a femtosecond laser [101].…”

Section: Lasers and Laser Produced Plasmamentioning

confidence: 99%

Forty Years of the Applications of Stark Broadening Data Determined with the Modified Semiempirical Method

Dimitrijević

2020

Data

View full text Add to dashboard Cite

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.

show abstract

“…It is widely used to characterize plasmas and plume formation when a metal vapor expands under vacuum (e.g., ablation) [8,9], for chemical analyses and quantification (e.g., the evaporation of compounds vs alloys) [10,11], and can be exploited in AM processes [12][13][14][15]. OES measures the electron densities and temperatures using excited species (atoms and molecules, neutral or ionized) in a plasma based on their radiative emission lines [16,17]. However, evaluating the ground-state density of a gas species by OES requires sophisticated modeling schemes such as the collisional-radiative model [18][19][20] because (1) the plasma is out of equilibrium and (2) excitation and ionization are highly nonlinear processes that depend mainly on the high-energy tail of the electron energy distribution function, which is hardly accessible using experimental techniques.…”

Section: Introductionmentioning

confidence: 99%

Saturation pressure of nonequilibrium titanium evaporation during additive manufacturing by electron powder bed fusion

Farsy

Antunes

Seznec

et al. 2022

Journal of Applied Physics

View full text Add to dashboard Cite

Electron beam powder bed fusion (E-PBF) is an attractive technology for the additive manufacturing of metal parts. However, process improvements require precise control of the energy transferred to the powder by the electron beam. Here, we used tunable diode laser absorption spectroscopy (TD-LAS) to measure the velocity distribution functions of titanium atoms evaporated during E-PBF. The narrow spectral ranges emitted by laser diodes allow for high-resolution absorption profiles of the evaporated atoms and thus accurate determinations of their Doppler broadening, density, and temperature during melting. The obtained vapor temperature reveals overheating at the surface of the melt pool relative to the low-pressure (0.1 Pa) boiling point of titanium, indicating that evaporation occurs under nonequilibrium conditions. We characterized the influence of the linear energy density on titanium evaporation and found it to be consistent with the saturation vapor pressure. Our characterization of the vapor properties provides reliable inputs for melt pool simulations. Furthermore, TD-LAS may be further exploited to prevent the evaporation of low-concentration alloy elements, which can induce defects in the printed part.

show abstract

Dependence of radiation decay constant of laser produced copper plasma on focal position

Cited by 12 publications

References 36 publications

Role of Focusing Distance in Picosecond Laser-Induced Cu Plasma Spectra

Role of Focusing Distance in Picosecond Laser-Induced Cu Plasma Spectra

Forty Years of the Applications of Stark Broadening Data Determined with the Modified Semiempirical Method

Saturation pressure of nonequilibrium titanium evaporation during additive manufacturing by electron powder bed fusion

Contact Info

Product

Resources

About