Spectrochemical Analysis of Liquids Using Laser-Induced Plasma Emissions: Effects of Laser Wavelength on Plasma Properties

1997 ◽  
Vol 51 (7) ◽  
pp. 976-983 ◽  
Author(s):  
C. W. Ng ◽  
W. F. Ho ◽  
N. H. Cheung
Keyword(s):  
Laser Ablation ◽  
Electron Density ◽  
Laser Wavelength ◽  
Plasma Properties ◽  
Sodium Potassium ◽  
Thermally Induced ◽  
Plasma Plumes ◽  
Plume Temperature ◽  
193 Nm ◽  
532 Nm

We spectroscopically determined the temperature and electron density of the plasma plumes produced by pulsed-laser ablation of aqueous solutions containing sodium, lithium, and rubidium. With the use of a Nd:YAG laser at 532 nm and fluence of 3 J/cm2, the plasma produced was hot (low eV range) and extensively ionized, with electron density in the 1018 cm−3 range. Analyte line signals were initially masked by intense plasma continuum emissions and would only emerge briefly above the background when the plume temperature dropped below 1 eV during the course of its very rapid cooling. Since ionization was thermally induced, the intense plasma flash was inevitable. In contrast, 193-nm laser ablation at similar fluence generated plasmas of much lower (<1 eV) temperature but comparable electron density. Plasma continuum emissions were relatively weak, and the signal-to-background ratio was a thousand times better. Consequently, this “cold” plasma was ideal for sampling biologically important elements such as sodium, potassium, and calcium.

Spectrochemical Analysis of Liquids Using Laser-Induced Plasma Emissions: Effects of Laser Wavelength

1997 ◽  
Vol 51 (1) ◽  
pp. 87-91 ◽  
Author(s):  
W. F. Ho ◽  
C. W. Ng ◽  
N. H. Cheung
Keyword(s):  
Laser Pulse ◽  
Signal To Noise Ratio ◽  
Laser Wavelength ◽  
Spectrochemical Analysis ◽  
Liquid Jets ◽  
Single Shot ◽  
Transient Nature ◽  
Vapor Plume ◽  
193 Nm ◽  
532 Nm

The plasma plume emissions produced by pulsed (∼ 10 ns) laser ablation of liquid jets were monitored for spectrochemical analysis. Laser wavelengths at 532 and 193 nm were used, and sodium was the test analyte. As expected, the 532-nm laser pulse produced very intense plasma continuum emissions that masked the sodium signal for the first hundred nanoseconds, especially near the bright core of the vapor plume. Neither time-gating nor spatial masking could significantly improve the single-shot signal-to-noise ratio, since the transient nature of the emissions placed stringent demands on timing precision while the small size of the plume required accurate mask positioning—both antithetical to the inherent instability of jet ablation. In sharp contrast, the 193-nm laser pulse produced relatively dim plasma flash but intense sodium emissions, rendering it ideal for analytical applications.

scholarly journals Laser Ablation Studies of Deposited Silver Colloids Active in SERS

2002 ◽  
Vol 20 (1) ◽  
pp. 23-32 ◽  
Author(s):  
R. Torres La Porte ◽  
D. Silva Moreno ◽  
M. Castillejo Striano ◽  
M. Martiín Munñoz ◽  
J. V. García-Ramos ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Temporal Resolution ◽  
Mass Spectroscopy ◽  
Mass Spectra ◽  
Time Of Flight ◽  
Laser Wavelength ◽  
Ablation Plume ◽  
Expansion Velocity ◽  
Silver Colloids ◽  
532 Nm

Laser ablation of deposited silver colloids, active in SERS, is carried out at three different laser wavelengths (KrF, XeCl and Nd:YAG at λ = 248, 308 and 532 nm respectively). Emission form excited neutral Ag and Na atoms, present in the ablation plume, is detected with spectral and temporal resolution. The expansion velocity of Ag in the plume is estimated in ~1×104m s−1. Low-fluence laser ablation of the colloids yields ionized species that are analyzed by time-of-flight mass spectroscopy. Na+ and Agn+(n≤3) are observed. Composition of the mass spectra and widths of the mass peaks are found to be dependent on laser wavelength, suggesting that the dominant ablation mechanisms are different at the different wavelenghts.

SYNTHESIZE OF GOLD NANOPARTICLES WITH 532 NM AND 1064 NM PULSE LASER ABLATION

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
W. Norsyuhada W. Shukri ◽  
Noriah Bidin ◽  
Syafiq Affandi ◽  
Siti Pauliena Bohari
Keyword(s):  
Gold Nanoparticles ◽  
Laser Ablation ◽  
Colloidal Particles ◽  
Second Harmonic ◽  
Laser Pulses ◽  
Laser Wavelength ◽  
Colloidal Solutions ◽  
Fundamental Wavelength ◽  
Responsible Mechanism ◽  
532 Nm

The effect of laser wavelength on gold nanoparticle fabrication is reported. Colloidal solutions of gold nanoparticles were prepared by pulsed laser ablation technique in deionized water. A Q-switched Nd:YAG laser with constant energy of 65mJ and operation at fundamental wavelength and second harmonic generation was utilized as a source of energy. Fabricated particles were characterized by using Smart Nanoparticles Measurements (SNM) system. The average diameters of gold nanoparticles achieved as19 nm and 12 nm corresponding to 1064 nm and 532 nm respectively. The fragmentation of colloidal particles by self-absorption of laser pulses is the responsible mechanism to cause for reduction.

Laser Wavelength Dependent Properties of BN Thin Films Deposited by Laser Ablation

1996 ◽  
Vol 423 ◽  
Author(s):  
Y. Suda ◽  
T. Nakazono ◽  
K. Ebihara ◽  
K. Baba
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Laser Wavelength ◽  
Nitrogen Gas ◽  
Mixture Ratio ◽  
Self Bias ◽  
Fourier Transform Ir ◽  
532 Nm

AbstractBoron Nitride (BN) thin films are deposited on heated (650 °C ) silicon (100) substrates using Nd:YAG (532 nm) and KrF excimer (248 nm) laser ablation. The laser beam is focused on the hBN targets. The films are grown using a laser repetition rate of 10 Hz atenergy density 3.8 J/cm2. Argon gas is mixed with the reactant nitrogen gas and the total gas pressure in the chamber during deposition is 20 Pa. Auger Electron Spectroscopy shows that the N/B composition ratio depends on the mixture ratio of nitrogen and the relativeemission intensity of B + (345.1 nm). The surface morphology of the films prepared by the 532 nm laser is rough with large particulates, whereas much smoother surfaces with fewer and smaller particulates are obtained with the 248 nm laser. Fourier Transform IR measurement shows that the cBN phase in the films is enhanced by applying the negative RF self-bias voltage ( ˜ 200 V) on the substrate electrode.

Linear and Nonlinear Optical Properties of Natural Dyes Freestanding Films and Application in Optical Limiting

2020 ◽  
pp. 139-143
Keyword(s):  
Absorption Coefficient ◽  
Water Solution ◽  
Optical Limiting ◽  
Refraction Index ◽  
Laser Wavelength ◽  
Solid State Laser ◽  
Natural Dyes ◽  
Linear And Nonlinear ◽  
532 Nm ◽  
Absorbance Spectra

Natural dyes were followed and prepared from a pomegranate, purple carrot, and eggplant peel. The absorbance spectra was measured in the wavelength range 300-800 nm. The linear properties measurements of the prepared natural dye freestanding films were determined include absorption coefficient (α0), extinction coefficient (κ), and linear refraction index (n). The nonlinear refractive index n2 and nonlinear absorption coefficient β2 of the natural dyes in the water solution were measured by the optical z-scan technique under a pumped solid state laser at a laser wavelength of 532 nm. The results indicated that the pomegranate dye can be promising candidates for optical limiting applications with significantly low optical limiting of 3.5 mW.

Detection and Characterization of an Electrical Failure Induced during Laser Ablation of Packages

2008 ◽  
Author(s):  
P. Schwindenhammer ◽  
H. Murray ◽  
P. Descamps ◽  
P. Poirier
Keyword(s):  
Laser Ablation ◽  
Integrated Circuits ◽  
Failure Analysis ◽  
Ablation Process ◽  
Thermally Induced ◽  
Electrical Failure ◽  
Electrical Phenomenon ◽  
Semiconductor Packages ◽  
Complex Semiconductor

Abstract Decapsulation of complex semiconductor packages for failure analysis is enhanced by laser ablation. If lasers are potentially dangerous for Integrated Circuits (IC) surface they also generate a thermal elevation of the package during the ablation process. During measurement of this temperature it was observed another and unexpected electrical phenomenon in the IC induced by laser. It is demonstrated that this new phenomenon is not thermally induced and occurs under certain ablation conditions.

Preparation of ZnO Nanoparticles by 1064/532nm Laser Ablation and Studying the Effect of the Ablation Wavelength

2021 ◽  
Vol 1021 ◽  
pp. 171-180
Author(s):  
Munaf S. Majeed ◽  
Rabea Q. Nafil ◽  
Marwa F. Abdul Jabbar ◽  
Kadhim H. Suffer
Keyword(s):  
Zinc Oxide ◽  
Laser Ablation ◽  
Pure Water ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Ultra Pure Water ◽  
Hexagonal Shape ◽  
532 Nm ◽  
Laser Ablation Technique

We prepared Zinc oxide nanomaterial employing PLA (pulsed laser ablation) technique. A pure Zn target was immersed in ultra-pure water (UPW) and it was subjected to several pulses (1st. and 2nd. harmonic) of the pumping Nd: YAG laser. The influence of changing laser’s wavelength (1064, 532) nm on the characterization of the produced nanoparticles was studied. The results obtained from studying the structure, topography, and morphology of the product showed that the particles have a hexagonal shape. Also, changing the wavelength of the laser from 532nm to 1064nm leads to size reduction and density increasing of the nanoparticles.

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