tungsten ion beam; double-pulse lasers ablation system; laser ablation system; optical Instrumentation;INDUCED BREAKDOWN SPECTROSCOPY; APPLIED ELECTRIC-FIELD; INDUCED PLASMA; SURFACE; SPECTROMETRY; DYNAMICS; WAVELENGTHS; NANOSECOND; PARAMETERS; RADIATION

New tungsten ion source is produced by using single and double-pulse laser ablation system. Combined collinear Nd:YAG laser beams (266+1064 nm) are optimized to focus on the sample in air. Optimization of the experimental parameters is achieved to enhance the signal-to-noise ratio of the emission spectra. The velocity distribution of the emitted plasma cloud is carefully measured. The influences of the potential difference between the bias electrodes, laserwavelength and intensity on the current signal are also studied. The results show that the increase in the tungsten ion velocity under the double-pulse lasers causes the output current signal to increase by about three folds. The electron density and temperature are calculated by using the Stark-broadened line profile of tungsten line and Boltzmann plot method of the upper energy levels, respectively. The signal intensity dependence of the tungsten ion angular distribution is also analyzed. The results indicate that the double-pulse laser ablation configuration is more potent technique for producing more metal ion source deposition, thin film formation, and activated plasma-facing component material.

Laser-induced breakdown spectroscopy; Instrument; Review;IN-SITU ANALYSIS; INDUCED PLASMA; QUANTITATIVE-ANALYSIS; MICROCHIP-LASER; SPECTROCHEMICAL ANALYSIS; GEOLOGICAL SAMPLES; RAMAN-SPECTROSCOPY; MATRIX CONVERSION; RAPID DETECTION; LIBS SYSTEM

Laser-induced breakdown spectroscopy (LIBS) has become a very attractive technique in the field of chemical analysis. The technique utilizes a laser focused on a small spot to create a micro-plasma on the sample surface. In recent years, LIBS is a frontier analysis technique in spectrometric analysis, with the advantages such as real-time, online and non-contact analysis. The research and development of various instruments based on this technology has attracted great attention of analysts. In this article, we reviewed the research progress of LIBS instrument from aspects of the components and field equipment in recent years, including portable LIBS, handheld LIBS and remote LIBS.

LASER-INDUCED BREAKDOWN; PLASMA-MASS SPECTROMETRY; RESOLUTION CONTINUUM SOURCE; PARTICLE ICP-MS; RAY-FLUORESCENCE SPECTROMETRY; MULTI-ANALYTICAL APPROACH; OPTICAL-EMISSION SPECTROSCOPY; LI-ION BATTERIES; ELECTRON-PARAMAGNETIC-RESONANCE; ELEMENTAL IMPURITIES ANALYSIS

This ASU review focuses on developments in applications of atomic spectrometry to the characterisation of metals, chemicals and materials. It is difficult to identify research trends solely from an annual review of the literature, but a certain perspective can be obtained from examining the developments described in recent years in this ASU review series. It is, for example, evident that there has been a decline in truly novel applications for the analysis of chemicals, perhaps indicative of the fact that, for most sample types, there is now an abundance of methods available in the literature. Those papers that have appeared in the year under review have either focused on specific problems not yet fully addressed (e.g. determination of Si in gasoline) or on incremental development of well-established approaches to sample preparation or measurement. Nevertheless, there has been a very noticeable increase in activity in relation to publication of methods for the characterisation of pharmaceuticals. This is directly linked to changes in the US Pharmacopeia requirements for registration of pharmaceuticals for human use that require assessments to be made for trace element content. Laser-induced breakdown spectrometry is becoming widely employed for applications involving the characterisation of a wide variety of metals, materials and other solid sample types. Efforts are being made to overcome the perceived weaknesses of the technique, such as lack of sensitivity, elemental fractionation, accuracy and/or precision. Advances have been made, for example, using dual-pulse lasers to improve sensitivity, or by employing chemometrics methods with full spectrum data to improve the robustness of calibration. Many of these reported LIBS developments draw from, and have relevance for, applications involving LA-ICP-MS, which continues to be a popular means of generating highly sensitive lateral and depth profiling and bulk compositional information for a wide range of materials and solids. The use of field portable instrumentation for in situ analysis continues grow, with LIBS and XRF techniques amongst those most frequently cited. The development of such instrumentation has had a substantial impact in the examination of cultural heritage artefacts, especially in relation to paintings, wall murals and other objects of unique historical value. The latter area of application has also seen continued use of combinations of surface (SIMS, XPS, SEM-EDS, PIXE, GD and laserablation methods) and bulk (ICP-OES, ICP-MS, AAS, XRF) analysis techniques to reveal details of objects that would not otherwise be identified (for example preparatory sketches hidden under original works of art or materials provenance). This trend towards using a multi-technique based approach has also been apparent in the characterisation of multi-layer or heterogeneous organic and inorganic materials and metals. Finally, methods for the analysis of nanoparticles and nanostructures have been reported, based primarily on single particle (SP)-ICP-MS and flow field flow fractionation (A4F). The investigation of methods of drift correction, the use of flow injection and isotope dilution methodologies in combination with SP-ICP-MS are indicative of the further development of this field.

ECHELLE SPECTROGRAPH; SPECTROMETER

High-resolution spectrographs extract detailed spectral information of a sample and are frequently used in astronomy, laser-induced breakdown spectroscopy, and Raman spectroscopy. These instruments employ dispersive elements such as prisms and diffraction gratings to spatially separate different wavelengths of light, which are then detected by a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) detector array. Precise alignment along the optical axis (focus position) of the detector array is critical to maximize the instrumental resolution; however, traditional approaches of scanning the detector through focus lack a quantitative measure of precision, limiting the repeatability and relying on one's experience. Here we propose a method to evaluate the focus alignment of spectrograph detector arrays by establishing confidence intervals to measure the alignment precision. We show that propagation of uncertainty can be used to estimate the variance in an alignment, thus providing a quantitative and repeatable means to evaluate the precision and confidence of an alignment. We test the approach by aligning the detector array of a prototype miniature echelle spectrograph. The results indicate that the procedure effectively quantifies alignment precision, enabling one to objectively determine when an alignment has reached an acceptable level. This quantitative approach also provides a foundation for further optimization, including automated alignment. Furthermore, the procedure introduced here can be extended to other alignment techniques that rely on numerically fitting data to a model, providing a general framework for evaluating the precision of alignment methods. (C) 2017 Optical Society of America

laser-induced; plasma emission; molecular spectra;INDUCED-BREAKDOWN-SPECTROSCOPY; LOCAL THERMAL-EQUILIBRIUM; GAS-PHASE REACTIONS; ELEMENTAL ANALYSIS; ISOTOPIC SPECTROMETRY; SELF-ABSORPTION; INDUCED FLUORESCENCE; TITANIUM MONOXIDE; ABLATION PLUMES; FEMTOSECOND

The aim of this paper is the description of the optical emission spectral features of the plasma produced by laser-matter interaction, from a fundamental point of view. The laser induced plasma emission spectra are discussed in connection with the basic mechanisms that take place in the plasma phase at different time delays from the laser pulse. The laser induced plasma being a dynamic system, the hierarchy of the elementary mechanisms changes continuously because the electron number density and the electron temperature decrease during the expansion. As a consequence of this, over the duration of the plasma's persistence the prevailing emitting species changes from ions to atoms and from atoms to molecules. Both atomic and molecular emission spectroscopy are discussed, to convey a complete description of the temporal evolution of laser induced plasma. Current literature, as well as the traditional plasma theories, are presented and discussed in order to give to the reader a general idea of the potentialities and drawbacks of emission spectroscopy in the study of laser induced plasma and its various applications.

Laser-induced breakdown spectroscopy; LIBS; Calibration-free LIBS; Limit of detection; Analytical sensitivity; Calibration; Spatial heterodyne spectroscopy;QUANTITATIVE-ANALYSIS; ELEMENTAL ANALYSIS; PLANT MATERIALS; MOISTURE-CONTENT; CARBON CONTENT; LIBS; COAL; IDENTIFICATION; SOIL; METHODOLOGY

The goal of this review article is to provide a description of recent and novel laser-induced breakdown spectroscopy (LIBS) applications and developments, especially those discussed during the NASLIBS Conference, held during SciX in Providence, RI, in September 2015. This topic was selected in view of the numerous recent overall review papers that have successfully given a broad view of the current understanding of laser-material interactions and plasma development and have also discussed the wide landscape of analytical applications of LIBS. This paper is divided into sections that focus on a few of the many applications under development in the LIBS community. We provide a summary of updates to calibration-free LIBS (CF-LIBS) and associated developments using plasma characteristics to improve quantification in LIBS output, both in a dedicated section and as applications are discussed. We have also described the most recent publications studying the sources, generation, and use of molecular features in LIBS, including those naturally present in the spectra of organic materials, and those induced with the addition of salts to enable the measurement of halogens, not typically present in LIBS signals. In terms of development of applications of LIBS, we focused on the use of LIBS for indirect measurements such as pH and degree of humification in soil and heating value in coal. We also reviewed the extant literature on LIBS analysis of agricultural materials, coal, minerals, and metals. Finally, we discuss the nascent developments of spatially heterodyne spectroscopy, a method that seeks to circumnavigate a serious drawback of most spectrometers - very small optical throughput - through the use of interferometers.

Laser-induced breakdown spectroscopy; remote LIBS; standoff LIBS; spatial heterodyne spectrometer; remote spectroscopy;IN-SITU ANALYSIS; RAMAN-SPECTROSCOPY; QUANTITATIVE-ANALYSIS; SOLID-SURFACES; SAMPLES; PLATFORM; PLASMA; SENSOR; PROBE

A spatial heterodyne spectrometer (SHS) is described for standoff laser-induced breakdown spectroscopy (LIBS) measurements. The spatial heterodyne LIBS spectrometer (SHLS) is a diffraction grating based interferometer with no moving parts that offers a very large field of view, high light throughput, and high spectral resolution in a small package. The field of view of the SHLS spectrometer is shown to be similar to 1 degrees in standoff LIBS measurements. In the SHLS system described here, the collection aperture was defined by the 10mm diffraction gratings in the SHS and standoff LIBS measurements were made up to 20m with no additional collection optics, corresponding to a collection solid angle of 0.2 mu sr, or f/2000, and also using a small telescope to increase the collection efficiency. The use of a microphone was demonstrated to rapidly optimize laser focus for 20m standoff LIBS measurements.

Laser-induced breakdown spectroscopy; LIBS; elemental identification; wavelength similarity coefficient;SEARCH ALGORITHMS; SPECTROSCOPY; PLASMA; LIBRARY

This work proposes a method to perform elemental identification on plasmas produced using the laser-induced breakdown spectroscopy (LIBS) technique. The method is based on the preservation of the relative relevance of the spectral line emission intensities, which is lost during the parametric correlation procedure, by the introduction of a similitude coefficient called wavelength similarity coefficient. Furthermore, it was shown that for identification purposes, a simplified plasma model is sufficient to predict adequately the relative emission intensities in LIBS plasmas. As a result, it is possible to automatically identify the species with high emission signals, while trace detection is also possible by relaxing search conditions, although manual refinement is still required.

Laser-induced breakdown spectroscopy; LIBS; lens-to-sample distance; sample positioning; repeatability;

A simple device based on two commercial laser pointers is described to assist in the analysis of samples that present uneven surfaces and/or irregular shapes using laser-induced breakdown spectroscopy (LIBS). The device allows for easy positioning of the sample surface at a reproducible distance from the focusing lens that conveys the laser pulse to generate the micro-plasma in a LIBS system, with reproducibility better than +/- 0.2 mm. In this way, fluctuations in the fluence (J cm(-2)) are minimized and the LIBS analytical signals can be obtained with a better precision even when samples with irregular surfaces are probed.

Laser-induced breakdown spectroscopy; LIBS; self-absorption; curve-of-growth; COG;INDUCED PLASMA; GROWTH; CURVES

Laser-induced breakdown spectroscopy (LIBS) is a widely used laser spectroscopic technique in various fields, such as material science, forensic science, biological science, and the chemical and pharmaceutical industries. In most LIBS work, the analysis is performed using radiative transitions from atomic emissions. In this study, the plasma temperature and the product Nl (the number density N and the absorption path length l) were determined to evaluate the optical depths and the self-absorption of Sr and Al lines. A binary mixture of strontium nitrate and aluminum oxide was used as a sample, consisting of variety of different concentrations in powder form. Laser-induced breakdown spectroscopy spectra were collected by varying various parameters, such as laserenergy, gate delay time, and gate width time to optimize the LIBS signals. Atomic emission from Sr and Al lines, as observed in the LIBS spectra of different sample compositions, was used to characterize the laser induced plasma and evaluate the optical depths and self-absorption of LIBS.

PARTICLE-ICP-MS; RAMAN-SPECTROSCOPY; NANOPARTICLES; SILVER

Analytical spectroscopy is a mature field, but advances in instrumentation, measurement, and sample preparation techniques continue to be made. Much recent development has seen a heavy emphasis toward techniques and instrumentation that allow for noninvasive, in situ, and in vivo procedures while still retaining a high degree of sensitivity. This article will review some of this progress over the past two to three years across five major spectroscopic fields: Raman, laser-induced breakdown spectroscopy, X-ray fluorescence, infrared, and inductively coupled plasma techniques.

INDUCED BREAKDOWN SPECTROSCOPY; PIGMENTS

France is one of the countries involved in the future E-RIHS - European Research Infrastructure for Heritage Science. The research infrastructure dedicated to the study of materials of cultural and natural heritage will provide transnational access to state-of-the-art technologies (synchrotron, ion beams, lasers, portable methods, etc.) and scientific archives. E-RIHS addresses the experimental problems of knowledge and conservation of heritage materials (collections of art and natural museums, monuments, archaeological sites, archives, libraries, etc.). The cultural artefacts are characterized by complementary methods at multi-scales. The variety and the hybrid are specific of these artefacts and induce complex problems that are not expected in traditional Natural Science: paints, ceramics and glasses, metals, palaeontological specimens, lithic materials, graphic documents, etc. E-RIHS develops in that purpose transnational access to distributed platforms in many European countries. Five complementary accesses are in this way available: FIXLAB (access to fixed platforms for synchrotron, neutrons, ion beams, lasers, etc.), MOLAB (access to mobile examination and analytical methods to study the works in situ), ARCHLAB (access to scientific archives kept in the cultural institutions), DIGILAB (access to a digital infrastructure for the processing of quantitative data, implementing a policy on (re) use of data, choice of data formats, etc.) and finally EXPERTLAB (panels of experts for the implementation of collaborative and multidisciplinary projects for the study, the analysis and the conservation of heritage works). Thus E-RIHS is specifically involved in complex studies for the development of advanced high-resolution analytical and imaging tools. The privileged field of intervention of the infrastructure is that of the study of large corpora, collections and architectural ensembles. Based on previous I3 European program, and especially IPERION-CH program that support the creation of new mobile instrumentation, the French institutions are involved in the development of LIBS/LIF/RAMAN portable instrumentation. After a presentation of the challenge and the multiple advantages in building the European Infrastructure and of the French E-RIHS hub, the major interests of associating the three lasers based on analytical methods for a more global and precise characterization of the heritage objects taking into account their precious characters and their specific constraints. Lastly some preliminary results will be presented in order to give a first idea of the power of this analytical tool.

Laser-induced breakdown spectroscopy; LIBS; imaging techniques; nanoparticles; fluorescence; magnetic resonance imaging;

The requirements for early diagnostics as well as effective treatment of insidious diseases such as cancer constantly increase the pressure on development of efficient and reliable methods for targeted drug/gene delivery as well as imaging of the treatment success/failure. One of the most recent approaches covering both the drug delivery as well as the imaging aspects is benefitting from the unique properties of nanomaterials. Therefore a new field called nanomedicine is attracting continuously growing attention. Nanoparticles, including fluorescent semiconductor nanocrystals (quantum dots) and magnetic nanoparticles, have proven their excellent properties for in vivo imaging techniques in a number of modalities such as magnetic resonance and fluorescence imaging, respectively. In this article, we review the main properties and applications of nanoparticles in various in vitro imaging techniques, including microscopy and/or laser breakdown spectroscopy and in vivo methods such as magnetic resonance imaging and/or fluorescence-based imaging. Moreover the advantages of the drug delivery performed by nanocarriers such as iron oxides, gold, biodegradable polymers, dendrimers, lipid based carriers such as liposomes or micelles are also highlighted.

Single pulse (SP) LIBS setup was modified to DP setup to achieve more accurate analytical sensitivity and spatial resolution. All parameters, like interpulse delay, acquisition delay or energy of ablation and excitation laser pulses were optimized.

Laser-ablation based spectrochemical Analytical Methods could be used in applications in which the capability for spatially resolved analysis is required. Such analysis gives a 2-D or 3-D map of the monitored chemical elements. Here we introduce automation of a 2-D surface analysis in the laser-induced breakdown spectroscopy setup by implementation of an autofocus algorithm based on the evaluation of the image sharpness. The most suitable algorithm with respect to its speed, accuracy, and durability against digital noise is chosen by testing different gradient-based methods and methods working in the frequency domain.