Temporal characterization of femtosecond laser pulses induced plasma for spectrochemical analysis of aluminum alloys

Laser-induced plasma temperature

Spark discharge assisted laser induced breakdown spectroscopy

Vibrational emission analysis of the CN molecules in laser-induced breakdown spectroscopy of organic compounds

Multichannel laser-induced breakdown spectrometry (LIBS) is used to generate selective chemical images for silver, titanium, and carbon from silicon photovoltaic cells. A 2.5 mJ pulsed nitrogen laser and a spectrometer using charge-coupled device detection were employed. LIBS images were acquired sequentially by moving the sample located on a motorized x-y translational stage step by step while storing the multichannel LIBS spectrum for each position of the sample, followed by computer-based reconstruction of two-dimensional selective images from intensity profiles at several wavelengths. Depth distributions of carbon impurities are also reported. Room temperature and atmospheric pressure operation as used here remove the restrictions on sample size exhibited by other surface analysis techniques used for imaging applications. Thus, the sample size in LIBS imaging is in principle unlimited. A LIBS experiment does not require a sample to be conductive. Therefore, virtually all materials can be imaged. Although LIBS is a typical example of destructive analytical technique, multichannel detection as demonstrated here confers the possibility to LIBS of obtaining multielement information from a given surface area. Lateral resolution of 80 μm and depth resolution of better than 13 nm were observed. The ultimate limitation to imaging the first layer of the surface in LIBS is the spectral signal-to-noise ratio as dictated by the ablation threshold of the material.

http://atarazanas.sci.uma.es/docs/articulos/16719918.pdf

Multielemental chemical imaging using laser-induced breakdown spectrometry.

Time-resolved optical emission spectrometry of Q-switched Nd:YAG laser-induced plasmas from copper targets in air at atmospheric pressure

We have studied the capacitor transfer type of flat-plate-transmission-line traveling wave excited atmospheric pressure nitrogen laser. Experiments were carried over a wide variety of parameters such as charging voltage, separation and angle of electrodes, capacitance of bank, inductance of switching circuit, and geometrical parameters of resonators. The theory is based upon the macroscopic properties of nitrogen discharges. Laser pulses were calculated by solving numerically the space-dependent rate equations for population and photon number densities. The theoretical predictions are in very good agreement with the experimental observations.

Experimental and theoretical investigation of a traveling wave excited TEA nitrogen laser

Investigation of TEA-TE nitrogen laser system

Time-resolved vibrational and rotational emission analysis of laser-produced plasma of carbon and polymers

A systematic study of the time evolution of the line shape of radiation emitted by a gold plasma and an exact line intensity calculation was carried out. The emission of the hot and dense plasma produced by a Q-switched Nd:YAG laser in atmospheric air was measured by a time-gated optical multichannel analyzer. Asymmetric Lorentz-type profile equations were tested for two gold lines (406.51, 389.79 nm) as a function of time. A strong broadening, asymmetry and shift is observable up to 800–1000 ns after the laser pulse. Spectral profiles of the delayed (with 0.8–1.0 μs) and time-integrated (gate time of 2.5 μs) measurements were found to be well represented by a symmetric Lorentz-type curve.

B. Német

Papers

Time-resolved optical emission spectrometry of Q-switched Nd:YAG laser-induced plasmas from copper targets in air at atmospheric pressure

Experimental and theoretical investigation of a traveling wave excited TEA nitrogen laser

Investigation of TEA-TE nitrogen laser system

Time-resolved vibrational and rotational emission analysis of laser-produced plasma of carbon and polymers

Time-resolved line shape studies of Nd : YAG laser-induced microplasmas arising from gold surfaces.