Journal Optics & Laser Technology

Spatial confinement effects on spectroscopic and morphological studies of nanosecond laser-ablated Zirconium

Author: Hayat, A. ; et. al.

Journal: Optics & Laser Technology (2017)

Fundamentals

DOI: 10.1016/j.optlastec.2017.05.037

Authors

Keywords

Laser-induced breakdown spectroscopy LIBS; Spatial confinement; Spectral emissions; Electron temperature;

Abstract

Spatial confinement effects on plasma parameters and surface morphology of laser ablated Zr are studied by introducing a metallic blocker. Nd:YAG laser at various fluencies ranging from 8 J cm to 32 J cm was employed as an irradiation source. All measurements were performed in the presence of Ar under different pressures. Confinement effects offered by metallic blocker are investigated by placing the blacker at different distances of 6 mm, 8 mm and 10 mm from the target surface. It is revealed from LIBS analysis that both plasma parameters i.e. excitation temperature and electron number density increase with increasing laser fluence due to enhancement in energy deposition. It is also observed that spatial confinement offered by metallic blocker is responsible for the enhancement of both electron temperature and electron number density of Zr plasma. This is true for all laser fluences and pressures of Ar. Maximum values of electron temperature and electron number density without blocker are 12,600 K and 14 x 10 cm respectively whereas, these values are enhanced to 15,000 K and 21 x 10 cm in the presence of blocker. The physical mechanisms responsible for the enhancement of Zr plasma parameters are plasma compression, confinement and pronounced collisional excitations due to reflection of shock waves. Scanning Electron Microscope analysis was performed to explore the surface morphology of laser ablated Zr. It reveals the formation of cones, cavities and ripples. These features become more distinct and well defined in the presence of blocker due to plasma confinement. The optimum combination of blocker distance, fluence and Ar pressure can identify the suitable conditions for defining the role of plasma parameters for surface structuring.

Area:

Plasma diagnostics ; Surface morphology

Material:

Zirconium

Elements:

Zr

Lines [nm]:

Zr I 350.13 nm Zr I 535.09 nm Zr I 538.24 nm Zr I 544.85 nm Zr I 550.21 nm Zr II 343.16 nm Zr II 383.68 nm

Emmision lines:
Zr II 343.16 nm
Zr I 350.13 nm
Zr II 383.68 nm
Zr I 535.09 nm
Zr I 538.24 nm
Zr I 544.85 nm
Zr I 550.21 nm

Enhancement mechanism of femtosecond double-pulse laser-induced Cu plasma spectroscopy

Author: Zhang Dan ; et. al.

Journal: Optics & Laser Technology (2017)

Fundamentals

DOI: 10.1016/j.optlastec.2017.05.010

Authors
Chen, A. M. ; Jiang, Y. F. ; Jin, M. X. ; Li, S. Y. ; Sui, L. Z. ; Wang, X. W. ; Wang, Y.

Keywords

Laser-induced breakdown spectroscopy; Femtosecond laser; Double-pulse; Enhancement mechanism;INDUCED BREAKDOWN SPECTROSCOPY; SIGNAL ENHANCEMENT; METALLIC SAMPLES; OPTICAL-EMISSION; ABLATION; NANOSECOND; SILICON; ALUMINUM; SINGLE; COPPER

Abstract

A dual-wavelength femtosecond double-pulse laser is used to induce the Cu plasma spectroscopy in air. The laser wavelengths are a fundamental wavelength (800 nm) and a second harmonic wavelength (400 nm) from Ti:sapphire laser. The inter-pulse delay of double-pulse is from 300 ps to 160 ps. The observed spectral intensity is dependent on the inter-pulse delay of the dual-wavelength femtosecond double-pulse. We analyze the characteristics of the plasma temperature and the electron number density on the inter-pulse delay of double-pulse with two different wavelengths. For 800 nm + 400 nm, the spectral emission enhancement is based on more material ablation. For 400 nm + 800 nm, the enhanced mechanism is plasma reheating effect. This study will provide a better way to understand the mechanism of femtosecond double-pulse LIBS. (C) 2017 Elsevier Ltd. All rights reserved.

Area:

Double pulse ; Femtosecond

Material:

Copper

Elements:

Cu

Lines [nm]:

Cu I 510.55 nm Cu I 515.32 nm Cu I 521.82 nm

Emmision lines:
Cu I 510.55 nm
Cu I 515.32 nm
Cu I 521.82 nm

Development of double-pulse lasers ablation system and electron paramagnetic resonance spectroscopy for direct spectral analysis of manganese doped PVA polymer

Author: Khalil, A. A. I. ; et. al.

Journal: Optics & Laser Technology (2017)

Fundamentals Applications

DOI: 10.1016/j.optlastec.2017.05.036

Authors
Morsy, M. A.

Keywords

Plasma; Laser; EPR; DP-LIBS; Mn-analysis; PVA polymer;INDUCED PLASMA SPECTROSCOPY; INDUCED BREAKDOWN SPECTROSCOPY; SINGLE; EPR; IDENTIFICATION; ULTRAVIOLET; CRYSTALS; LIBS

Abstract

Series of manganese-co-precipitated poly (vinyl alcohol) (PVA) polymer were quantitatively and qualitatively analyzed using laser ablation system (LAS) based on double-pulse laser induced breakdown spectroscopy (DP-LIBS) and electron paramagnetic resonance (EPR) spectroscopy. The collinear nanosecond laser beams of 266 and 1064 nm were optimized to focus on the surface of the PVA polymer target. Both laser beams were employed to estimate the natural properties of the excited Mn-PVA plasma, such as electron number density (Ne), electron temperature (T-e), and Mn concentration. Individual transition lines of manganese (Mn), carbon (C), lithium (Li), hydrogen (H) and oxygen (0) atoms are identified based on the NIST spectral database. The results show better responses with DP-LIBS than the single-pulse laser induced breakdown spectroscopy (SP-LIBS). On the other hand, the EPR investigation shows characteristic broad peak of Mn-nano-particles (Mn-NPs) in the range of quantum dots of superparamagnetic materials. The line width (peak-to-peak, triangle H-pp) and g-value of the observed Mn-EPR peak are similar to 20 mT and 2.0046, respectively. The intensities of Mn-emission line at a wavelength 403.07 nm and the Mn-EPR absorption peak were used to accurate quantify the Mn-content in the polymer matrix. The results produce linear trends within the studied concentration range with regression coefficient (R-2) value of similar to 0.99, and limit of detection (LOD) of 0.026 mol.% and 0.016 mol.%, respectively. The LOD values are at a fold change of about -0.2 of the studied lowest mol.%. The proposed protocols of trace element detection are of significant advantage and can be applied to the other metal analysis. (C) 2017 Elsevier Ltd. All rights reserved.

Area:

Double pulse ; Plasma diagnostics

Material:

PVA polymer

Elements:

Mn

Lines [nm]:

Mn II 254.98 nm Mn II 255.19 nm Mn II 255.94 nm Mn II 343.90 nm Mn II 288.67 nm Mn II 296.17 nm Mn II 344.20 nm Mn I 280.11 nm Mn I 284.03 nm Mn I 356.95 nm Mn I 369.66 nm Mn I 401.81 nm Mn I 403.08 nm Mn I 404.88 nm Mn I 405.55 nm Mn I 405.89 nm Mn I 406.35 nm Mn I 407.94 nm Mn I 408.29 nm Mn I 423.51 nm Mn I 441.49 nm Mn I 445.16 nm Mn I 475.40 nm Mn I 478.34 nm Mn I 482.35 nm

C

Lines [nm]:

C II 515.11 nm C II 588.98 nm C II 723.64 nm

Li

Lines [nm]:

Li I 497.18 nm Li I 610.35 nm

O

Lines [nm]:

O I 747.64 nm O I 777.19 nm

H

Lines [nm]:

H I 656.29 nm

Emmision lines:
Mn II 254.98 nm
Mn II 255.19 nm
Mn II 255.94 nm
Mn I 280.11 nm
Mn I 284.03 nm
Mn II 288.67 nm
Mn II 296.17 nm
Mn II 343.90 nm
Mn II 344.20 nm
Mn I 356.95 nm
Mn I 369.66 nm
Mn I 401.81 nm
Mn I 403.08 nm
Mn I 404.88 nm
Mn I 405.55 nm
Mn I 405.89 nm
Mn I 406.35 nm
Mn I 407.94 nm
Mn I 408.29 nm
Mn I 423.51 nm
Mn I 441.49 nm
Mn I 445.16 nm
Mn I 475.40 nm
Mn I 478.34 nm
Mn I 482.35 nm
Li I 497.18 nm
C II 515.11 nm
C II 588.98 nm
Li I 610.35 nm
H I 656.29 nm
C II 723.64 nm
O I 747.64 nm
O I 777.19 nm

Emission enhancement of femtosecond laser-induced breakdown spectroscopy by combining nanoparticle and dual-pulse on crystal SiO2

Author: Yang, F. ; et. al.

Journal: Optics & Laser Technology (2017)

Fundamentals

DOI: 10.1016/j.optlastec.2017.03.016

Authors
Cao, Z. T. ; Jiang, L. ; Liu, L. ; Lu, Y. F. ; Wang, M. M. ; Wang, S. M.

Keywords

Femtosecond laser; Laser-induced breakdown spectroscopy; Nanoparticle; Double pulse;FIELD ENHANCEMENT; METALLIC SAMPLES; PLASMA; LIBS; CONFINEMENT; IMPROVEMENT; DISCHARGE; ABLATION; SURFACE; ARRAYS

Abstract

Metal nanoparticle deposition on sample surface is a promising approach to enhance the emission signal during laser-induced breakdown spectroscopy(LIBS). In this article, strong optical emission enhancement was achieved by combining nanoparticle enhanced LIBS (NELIBS) and double pulse LIBS (DP-LIBS) on a crystal SiO2 sample by using femtosecond laser. Thermal dewetting was used to deposit gold (Au) nanoparticles (NPs) on sample surface and NPs with different size were obtained by altering the thickness of the Au film. It was found that both the size and distribution of Au NPs significantly affected the enhancement effect of NELIBS and the Au NPs made from 7.5 nm gold film had the best enhancement effect. The fundamental features of NELIBS enhancement for dielectric target were investigated by studying the photon absorption process. At a low laser fluence of 4.4 J/cm(2), an enhancement factor of about 13 for spectrum intensity was obtained in NELIBS and reached to 30 after being combined with DP-LIBS. (C) 2017 Elsevier Ltd. All rights reserved.

Area:

Nanoparticles enhanced

Material:

Gold ; Nanoparticle ; Silicone dioxide

Elements:

Si

Lines [nm]:

Si I 288.16 nm Si I 243.52 nm Si I 250.69 nm Si I 251.43 nm Si I 251.61 nm Si I 252.85 nm Si I 263.13 nm Si I 390.55 nm

Au

Lines [nm]:

Au I 242.80 nm

Emmision lines:
Au I 242.80 nm
Si I 243.52 nm
Si I 250.69 nm
Si I 251.43 nm
Si I 251.61 nm
Si I 252.85 nm
Si I 263.13 nm
Si I 288.16 nm
Si I 390.55 nm

Journal: Optics & Laser Technology

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