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Optical diagnostics is a known and powerful tool to obtain information concerning the processes involved inside and around plasma. In the case of helium plasmas, they are present in industrial applications, like welding or cutting processes and in scientific research, like the inertial confinement plasmas or astrophysical analysis. This work reports information on the pressure broadened profiles of the HEII Paschen-alpha (Pα), Paschen-beta (Pβ) and Paschen-gamma (Pγ) spectral lines measured in a pulsed discharge lamp. Information relative to the line shapes, full width at 1/2, 1/4 and 1/8 of the maximum intensity and the dip of the HEII 320.3 nm is provided. The electron density has been determined by two-wavelength interferometry and from the Stark width of the HEI 501.6 nm and ranges during the HeII emission from 0.54 to 0.64 1023 m-3 in the plasma. Temperature (1.7 - 2.4 eV) has been simultaneously determined from the Boltzmann-plot of HEI and from local thermodynamic equilibrium (LTE) assumptions. The final results have been compared with most of the previous existing data.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) are frequent techniques performed to correct ametropia. Both methods have been compared in their way of healing but there is not comparison about transmittance and light scattering during this process. Scattering in corneal wound healing is due to three parameters: cellular size and density, and the size of scar. Increase in the scattering angular width implies a decrease the contrast sensitivity. During wound healing keratocytes activation is induced and these cells become into fibroblasts and myofibroblasts. Hens were operated using PRK and LASIK techniques. Animals used in this experiment were euthanized, and immediately their corneas were removed and placed carefully into a cornea camera support. All optical measurements have been done with a scatterometer constructed in our laboratory. Scattering measurements are correlated with the transmittance -- the smaller transmittance is the bigger scattering is. The aim of this work is to provide experimental data of the corneal transparency and scattering, in order to supply data that they allow generate a more complete model of the corneal transparency.

RESEARCH LINES OF THE OPTICS DEPARTMENTpi UNWERSITY OF VALLADOLID.Santiago Mar, Fernando Munoz, Juan Gonzalez, Angel M. de Frutos, Marco A. Gigosos, M Inmaculada de laRosa, M Concepcion Perez, Carlos Baladron, Juan Antonio Aparicio, Juan Antonio del Vat, Manuel Angel Gonzalez,Luis M Fuentes, Victor Gonzalez, Andres Bustilo, Ana Belen Gonzalo, Raal Pastor, Maria C. Gonzalez, AlbertoBarbes, Raul GarcIa, Anabel Manchon, Ricardo Vergaz, Prudencio Herrero, MarIa J. Martin, Ramon Margarida,Alberto Beijon.Dpto. Optica y Fisica Aplicada. Facultad de Ciencias.Prado de la Magdalena s/n .