Aluminium thin films depth profiling using LIBS

Abstract Laser Induced Breakdown Spectroscopy (LIBS) is an analytical technique used to classify and potentially quantify elements in complex hosts (or matrices) [1,2]. In this study, silicon based aluminium thin films were developed to study the depth profile and ablation rate of the material. Five films with different thicknesses from 1mm to 1.5 micron were used. The experimental setup consisted of s single pulse system with a Nd:YAG laser (1064 nm, up to 450 mJ, pulse duration 6 ns) used to irradiate the samples, an optic fibre spectrometer was used to detect the spectrum. The results show low ablation rate with time integrated method

Resonant Laser Ionization and Fine-Structure Study of Silver in an Ablation Plume

We report on a laser photo-ionization study of silver in relation to the Selective Production of Exotic Species (SPES) project at INFN-LNL in the offline laser laboratory. In this study, two dye lasers and an ablation laser operating at 10 Hz are used alongside a time-of-flight mass spectrometer (TOF-MS). Isotopic separation of the natural, stable isotopes 107Ag and 109Ag was clearly observed in the TOF signal. Resonant photo-ionization of silver was achieved with the use of the scheme 4d105s 2S1/2→ 4d105p 2Po3/2→ 4d106d 2D3/2 with transition wavelengths of 328.163 nm and 421.402 nm, respectively. Doppler-suppressed spectroscopy of these transition lines was performed in an ablation plume. Doppler broadening with collinear injection of excitation lasers and the effect of the linewidths of the excitation lasers were investigated. The fine-structure splitting of the level 4d106d 2D (J = 5/2 and J = 3/2) was confirmed to be 186 ± 2 pm, corresponding to 314 ± 3 GHz

EUV Multilayer Optics: Design, Development and Metrology

Extreme ultraviolet (EUV) multilayer coatings are presently widely used in both science and technology. The most characteristic technological application of multilayers is in lithography (EUVL) for large volume production of electronic chips. According to the well known Moore\u2019s law the density of components in integrated circuits doubles every about 18 months; the resolution in the processing of the wafer has to improve correspondingly. Since the lithographic process consists of the projection of a mask on the wafer, according to the optics diffraction limit in order to improve the resolution the wavelength of radiation has to decrease. Accordingly, effort is concentrated on the development of a lithographic tool at 13.5 nm in order to reach a resolution down to about 30 nm.1 In science the applications of multilayers are widely spread among beam lines of large scale facilities such as synchrotrons and free electron lasers (FELs), and for astronomy. At large scale facilities multilayer optics are used in order to select bandwidth or polarization and to focus the radiation beam. In astronomy multilayers are used in Solar imagers working at selected wavelengths for spectroscopic diagnostic purposes. More recently multilayer coatings for ultrashort pulses in the sub-femtosecond regime have been developed. By designing multilayers capable of reflecting or even compressing ultra-short pulses the \u201cmagic\u201d door to atto-physics has been opened. To give a classical perspective a few tens of attoseconds correspond approximately to the time an electron takes to complete one orbit around the nucleus of a hydrogen atom; in the same time the electric field of an optical pulse makes a small fraction of its oscillation. Understanding the physics at such short time scales represents a great challenge both for theory and experiment and can provide amazing results. In this review after a short general discussion of the basic theory of multilayers coatings some recent results in the development of multilayers for ultrashort pulses and astronomical applications will be presented. In the EUV spectral range transparent materials do not exist; only fluorides have relatively good transmittance at short wavelengths, with LiF presenting the shortest absorption edge at about 105 nm. This means that all materials have complex refractive indices with non- negligible imaginary coefficients, and that it is not possible to make use of refractive optics, such as lenses, prisms, plates or windows, in order to focus or steer the radiation in experimental set-up. Thus, in principle, it is only possible to use optics working in reflection, but in this case a further problem arises as a result of the low normal incidence reflectivity of standard metal coatings such as gold, and platinum. This is because at such short wavelengths the real parts of the refractive indices are very close to 274 Short Wavelength Laboratory Sources: Principles and Practices unity and, consequently, in order to get efficient reflection the coatings have to be used at very small glancing angles, below the critical angle for total reflection. This means that the optical apertures are very small, affecting the final throughput of the system and giving aberrations that are considerably larger than at near-normal incidence, thus further affecting the final performances. For these reasons, the design of optical coatings with high reflectivity at nearly normal incidence is strongly required. Multilayer coatings (multilayers or ML) consist basically of structures obtained through the repetition of bilayers made of two materials. The materials are selected in order to get the highest reflectivity at the interfaces and in addition their thickness is optimized in order to provide coherent superposition of the various reflected components. The working principle is similar to that of dielectric coatings widely used in the optical range, for example filters and laser mirrors. However since at such short wavelengths the thickness of the layers scales down to a few nm\u2019s new technological problems need to be solved

Evidence of Anomalous Multiplet Line Shapes in Optically Thick Laser-Produced, Plasmas

We report observations of anomalous line shapes for the transitions 2p−3d (2P−2D) emitted by the Li-like ions N(V), O(VI), F(VII) in laser-produced plasmas. These transitions are normally doublets but show completely different characteristics (e.g., triplet structures or invension of two-component intensity ratios) in the plasmas. The observed line profiles are accounted for in terms of opacity and Doppler effect produced by plasma expansion. This interpretation is independent of the particular transition involved, i.e., multiplet structures can generate more complicated features with various unexpected new components, anomalous intensity ratios, etc

Waste processing: New near infrared technologies for material identification and selection

The awareness of environmental issues on a global scale increases the opportunities for waste handling companies. Recovery is set to become all the more important in areas such as waste selection, minerals processing, electronic scrap, metal and plastic recycling, refuse and the food industry. Effective recycling relies on effective sorting. Sorting is a fundamental step of the waste disposal/recovery process. The big players in the sorting market are pushing for the development of new technologies to cope with literally any type of waste. The purpose of this tutorial is to gain an understanding of waste management, frameworks, strategies, and components that are current and emerging in the field. A particular focus is given to spectroscopic techniques that pertains the material selection process with a greater emphasis placed on the NIR technology for material identification. Three different studies that make use of NIR technology are shown, they are an example of some of the possible applications and the excellent results that can be achieved with this technique

Satellite Spectra from Laser-produced Plasmas of Be, B, C, N and O in He-like and Li-like Configurations

Satellite lines near the resonance lines in He-like and Li-like configurations have been observed in laser-produced plasmas of Be, B, C, N, and O. The observations have been made with a grazing incidence spectrograph with spatial resolution. These lines have been identified and compared with the existing theoretical predictions. Their intensities have been measured relative to the accompanying resonance lines