New Perspective on Thermally Stimulated Luminescence and Crystallization of Barium Borate Oxyfluoride Glasses

The demand for modern materials, especially glasses, used in different applications, such as radiation sensors and spectral converters, requires a detailed study of their properties. The incorporation of fluoride compounds in borate glasses and their crystallization at the nanometric scale allows the properties of these materials to be further enhanced. Although many works showed improvements in some of these properties, some critical aspects, such as the crystallization mechanism and the role of the fluorine phase, need more investigation. We worked with xNaF (100 − x)BaO·2B2O3 glasses with x = 0, 5, 10, 15, 20, 25, 30, and 35% (in mol) to increase the knowledge in this field. The structural modifications and the thermally stimulated luminescence of the glasses were studied, and their crystallization was analyzed by thermal analysis and X-ray diffraction. A continuous trap distribution was found, which was responsible for its very good luminescent signal, especially in glasses with 20% NaF. By selecting a suitable amount of NaF, it is possible to obtain nanocrystals of BaF2. These promising results we reached show the applicability of these materials.

Enhanced XUV harmonics generation from diatomic gases using two orthogonally polarized laser fields

Enhanced high repetition rate coherent extreme ultraviolet (XUV) harmonics represent efficient probe of electron dynamics in atoms, molecules and solids. In this work, we used orthogonally-polarized two-color laser field to generate strong even and odd high order harmonics from molecular gas targets. The dynamics of odd and even harmonics from O2, and N2 gases were investigated by employing single- and two-color laser fields using the fundamental radiation and second harmonic of 1030 nm, 37 fs, 50 kHz pulses. The relative efficiencies of harmonics were analyzed as a function of the thickness of the barium borate crystal used for second harmonic generation. Defocusing-assisted phase matching conditions were achieved in N2 gas for different groups of XUV harmonics.