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Rull F.,University of Valladolid | Sansano A.,University of Valladolid | Diaz E.,Instituto Nacional Of Tecnica Aerospacial Inta | Canora C.P.,S.A. INSA | And 16 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

The Raman Laser Spectrometer (RLS) is one of the Pasteur Payload instruments, within the ESA's Aurora Exploration Programme, ExoMars mission. The RLS Instrument will perform Raman spectroscopy on crushed powered samples deposited on a small container after crushing the cores obtained by the Rover's drill system. This is the first time that a Raman spectrometer will be launched in an out planetary mission. The Instrument will be accommodated and operate inside the Rover's ALD (Analytical Laboratory Drawer), complying with COSPAR (Committee on Space Research) Planetary Protection requirements. The RLS Instrument is composed by the following units: • SPU (Spectrometer Unit); • iOH: (Internal Optical Head); • ICEU (Instrument Control and Excitation Unit). Other instrument units are EH (Electrical Harness), OH (Optical Harness) and RLS SW On-Board. © 2010 Copyright SPIE - The International Society for Optical Engineering.


Rull F.,University of Valladolid | Sansano A.,University of Valladolid | Diaz E.,Instituto Nacional Of Tecnica Aerospacial Inta | Canora C.P.,S.A. INSA | And 17 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

The Raman Laser Spectrometer (RLS) is one of the Pasteur Payload instruments, within the ESA's Aurora Exploration Programme, ExoMars mission. ExoMars 2018 main Scientific objective is "Searching for evidence of past and present life on Mars". Raman Spectroscopy is used to analyze the vibrational modes of a substance either in the solid, liquid or gas state. It relies on the inelastic scattering (Raman Scattering) of monochromatic light produced by atoms and molecules. The radiation-matter interaction results in the energy of the exciting photons to be shifted up or down. The shift in energy appears as a spectral distribution and therefore provides an unique fingerprint by which the substances can be identified and structurally analyzed. The RLS is being developed by an European Consortium composed by Spanish, French, German and UK partners. It will perform Raman spectroscopy on crushed powdered samples inside the Rover's Analytical Laboratory Drawer. Instrument performances are being evaluated by means of simulation tools and development of an instrument prototype. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).


Vargas J.,Instituto Nacional Of Tecnica Aerospacial Inta | Gomez-Pedrero J.A.,Complutense University of Madrid | Alonso J.,Complutense University of Madrid | Quiroga J.A.,Complutense University of Madrid
Applied Optics | Year: 2010

This paper presents a deflectometric technique to measure the power of an ophthalmic lens as perceived by the user. It is based on a calibrated camera acting as a pinhole in order to measure ray deflection along the same path as the visual axis when the lens is held in front of the eye. We have analyzed numerically the accuracy of our technique, and it has been compared experimentally with a commercial "lens mapper" and with the real user power calculated from the measured topography of the lens surfaces to state the reliability and accuracy of the presented technique. © 2010 Optical Society of America.


Thibault F.,Rennes Institute of Physics | Gomez L.,Instituto Nacional Of Tecnica Aerospacial Inta | Ivanov S.V.,Russian Academy of Sciences | Buzykin O.G.,Central Aerohydrodynamic Institute TsAGI | Boulet C.,University Paris - Sud
Journal of Quantitative Spectroscopy and Radiative Transfer | Year: 2012

We perform dynamical calculations on two robust N 2-N 2 potential energy surfaces in order to intercompare pressure broadening coefficients derived from close coupling and coupled states quantum dynamical methods, the semi-classical model of Robert and Bonamy and a full classical method. The coupled states and full classical results compare well with the experimental results or with close coupling values when available. This study confirms that the classical method is a good alternative at room and high temperatures to quantum dynamical methods. The results obtained using the semi-classical method however deviate from the other sets of data at all temperatures considered here (77-2400K). © 2012 Elsevier Ltd.


Zubko E.,University of Kharkiv | Videen G.,Space Science Institute | Videen G.,Instituto Nacional Of Tecnica Aerospacial Inta | Videen G.,University of Cantabria | And 4 more authors.
Planetary and Space Science | Year: 2016

We examine the dispersion of the degree of linear polarization P in comets at phase angle ∼90° where the maximum amplitude of positive polarization Pmax occurs. The range of polarization observed in comets is from 7% up to more than 30%, and this cannot be explained through depolarization by gaseous emissions. Instead, we suggest that the observed dispersion of P results from different properties in cometary dust. We simulate the spectral polarimetric observations of comets using model agglomerated debris particles. The vast majority of observations can be reproduced with a mixture of weakly absorbing and highly absorbing agglomerated debris particles, which obey the same power-law size distribution. Within this extremely simple approach, polarization at side-scattering angles in a given comet is governed by the relative abundance of weakly and strongly absorbing particles. We find that in comets with the highest polarization, the weakly absorbing particles appear in proportions of only 14-23% by volume; whereas, in comets with the lowest polarization Pmax, their abundance is much greater, 82-95%. We conclude that the polarization at side-scattering angles unambiguously measures the relative abundance of Mg-rich silicates and refractory organics or amorphous carbon in comets. We put forth a hypothesis that low Pmax could be an indicator for presence of a well-developed refractory surface layer covering cometary nucleus. © 2015 Elsevier Ltd. All rights reserved.


Klacka J.,Comenius University | Kocifaj M.,Comenius University | Kocifaj M.,Slovak Academy of Sciences | Kundracik F.,Comenius University | And 3 more authors.
Journal of Quantitative Spectroscopy and Radiative Transfer | Year: 2015

The explicit solution to Maxwell's equations that satisfies the continuity equation is obtained for electrically charged spherical particles. The traditional separation-of-variables method (SVM) cannot be used to solve the vector wave equation for a non-uniformly charged spherical particle. In addition, a perturbation approach to the electromagnetic scattering problem fails if a spherical particle is occupied by electric charges that are not spatially homogeneous. By incorporating a correction to the conventional surface-current density, we have refined the conductivity model and found that the Rayleigh approximation (for mode n=1) is not a valid approach for modelling the optical effects by electrically charged particles much smaller than the wavelength of an incident radiation. Theoretical analyses indicate that peak enhancements of optical signatures are usually relevant in the long-wavelength limit due to the necessity to include higher-order modes of vibration (n>. 1). © 2015 Elsevier Ltd.


Kocifaj M.,Slovak Academy of Sciences | Kocifaj M.,Comenius University | Kundracik F.,Comenius University | Videen G.,Instituto Nacional Of Tecnica Aerospacial Inta | Videen G.,U.S. Army
Journal of Quantitative Spectroscopy and Radiative Transfer | Year: 2016

The dependence of the electric potential on the absorption and scattering of light by small particles has emerged as an interesting research topic, as the unexpected amplified optical signatures of a system of electrically charged particles were satisfactory predicted recently for homogeneous, uniformly charged spheres. However, natural particles are rarely of spherical shape. A comprehensive understanding of how arbitrarily shaped, charged particles interact with electromagnetic radiation has been missing. The approach we present here attempts to fill this gap by introducing a numerical formulation of the electromagnetic scattering problem for these particles. The first results from the intercomparison of numerical and analytical solutions for a pseudosphere show that the resonance features found are largely consistent, except for the magnitude and width of the peak amplitude, which may be due to inherent differences in the approaches used. © 2016 Elsevier Ltd


Barreda A.I.,University of Cantabria | Sanz J.M.,University of Cantabria | Alcaraz de la Osa R.,University of Cantabria | Saiz J.M.,University of Cantabria | And 5 more authors.
Journal of Quantitative Spectroscopy and Radiative Transfer | Year: 2015

We study the effect of contaminants on the resonances of silicon nanoparticles (NPs) by considering the spectral evolution of the degree of linear polarization of light scattered at right angles to the incident beam, PL(90°). From an optical point of view, a decrease in the purity of silicon nanoparticles due to the presence of contaminants impacts the NP effective refractive index. We analyze this effect for a silicon nanosphere (R=200. nm) suspended in different media. We focus on the spectral range where the quadrupolar magnetic, dipolar electric and dipolar magnetic resonances appear. The weakness of the resonances induced on the PL(90°) spectrum by the lack of purity can be used to quantify the contamination of the material. In addition, it is shown that Kerker conditions also suffer from a spectral shift, that is quantified as a function of material purity. © 2015 Elsevier Ltd.


Kundracik F.,Comenius University | Kocifaj M.,Comenius University | Kocifaj M.,Slovak Academy of Sciences | Videen G.,U.S. Army | And 3 more authors.
Applied Optics | Year: 2015

The mechanism of charge on the near-field intensity distribution is revealed for metallic and dielectric particles with sizes ranging from 10 nm to 10 μm. The theoretical foundation of near-field intensity perturbations is in the discontinuity of the tangential components of the magnetic fields on either side of the interface between the particle and its surrounding medium, since excess electrons form a thin metal-like layer with elevated conductivity. We have shown that the local fields alter marginally if charges are imposed on a surface of a metallic particle. But an intensity amplification is identified in the vicinity of charged dielectric particles with sizes smaller than the wavelength. Specifically, we have demonstrated that the electromagnetic field is amplified near the poles of the particle as a result of the oriented electric and incident fields. In contrast, a dielectric particle that is large compared to the wavelength becomes opaque with a deep shadow at the side opposite to the beam incidence. As a result, intensity damping is identified near a charged sphere in the geometric optics regime. At significant charge densities, the physical properties of a conductive layer play a dominant role in forming the 3D intensity distribution independent of conductivity or permittivity of the particle core. These findings suggest that some electrically chargeable particles have the potential to be used as optical devices with properties tunable through their net surface charge. © 2015 Optical Society of America.


Yuffa A.J.,U.S. Army | Gutierrez Y.,University of Cantabria | Sanz J.M.,University of Cantabria | De La Osa R.A.,University of Cantabria | And 6 more authors.
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2015

The near-field electromagnetic scattering intensity resonances are redshifted in frequency with respect to their far-field counterparts.We derive simple, approximate, analytical formulas for this shift in the case of a plane wave interacting with a dielectric sphere. Numerical results comparing the approximate formulas to the numerically exact solutions show that the two are in good agreement. We also consider the Rayleigh limit of the formulas to gain more insight into the phenomenon. © 2015 Optical Society of America.

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