Glass and Optical Materials: Optical Materials II
Sponsored by: MS&T Organization
Program Organizers: Pierre Lucas, University of Arizona

Tuesday 10:00 AM
October 18, 2011
Room: C111
Location: Greater Columbus Convention Center

Session Chair: John Ballato, Clemson University

10:00 AM
Tailoring Glasses for Lasers and Optical Biosensors: Andrea Armani¹; Heather Hunt¹; Brian Rose¹; Simin Mehrabani¹; Ashley Maker¹; Kelvin Kuo¹; Rasheeda Hawk¹; ¹University of Southern California
    Optical microcavities have applications ranging from biodetection to telecommunications. They are conventionally fabricated from thermal oxides or optical fiber. These materials provide limited options for the incorporation of dopants, restricting the development of active devices like lasers. Additionally, it is difficult to tune many of the material optical properties, such as the refractive index. It has recently been demonstrated that it is possible to fabricate these devices using sol-gel silica without impacting the optical performance of the microcavity device, opening the possibility to create a numerous active structures. For example, co-doped microcavity lasers with record thresholds based on a Yb:Er sol-gel system have demonstrated. This microlaser work, as well as other research relating to tailoring the refractive index and using these devices as biosensors will be discussed.

10:40 AM
Association of Defects with Antimony Luminescence Centers in Calcium Fluorapatite Phosphors: Eric Kreidler¹; ¹American Ceramic Society
    For over 65 years calcium fluorapatite doped with antimony and manganese has been the most important fluorescent lamp phosphor. Antimony is the primary absorber of ultraviolet radiation and occurs in two efficient and distinctly different centers. The emission in commercial phosphors has 88% quantum efficiency, maximum intensity at 480nm, and occurs when antimony pairs with oxygen ions located at nearest neighbor fluorine sites. In Kroger-Vink notation the fluorescence center is [Sb_Ca^.-F_F'] and electrostatic attraction causes pairing. The pair has strong infrared absorption at 14.6μ whose intensity is linearly correlated with both the antimony concentration and the intensity of the 480nm emission. The other center occurs when a fluorine ion is located at the adjacent fluorine site [Sb_Ca^.-F_F°] and charge compensation of the antimony is by Na_Ca' or V_Ca'' defects located at more distant lattice sites. When sodium compensated, the [Sb_Ca^.-F_F°] center emits at 400nm with 72% quantum efficiency.

11:00 AM
Chalcogenide Glasses and Glass-Ceramics for Novel Infrared Technologies: Jean-Luc Adam¹; Xiang-Hua Zhang¹; Johann Trolès¹; Laurent Brilland²; Virginie Nazabal¹; ¹Université de Rennes 1 - CNRS; ²PERFOS
    Chalcogenide glasses are materials of high interest for new applications in information and communication technologies, at wavelengths that are not accessible with silica-based devices. The latest results will be presented in challenging fields like (i) mid-infrared sources, in the 3-5 µm atmospheric window, where chalcogenide glasses possess a high potential for applications, (ii) Photonic crystal fibers (PCF) based on chalcogenide glasses, which are a new domain of research that might lead to new devices with unique optical properties in the mid-infrared domain like multimode or endlessly single-mode transmission of light, small or large mode area fibers, non-linear properties for all-optical regeneration of signals or generation of supercontinuum sources, (iii) S- and Se-based glass-ceramics highly transparent in the infrared, with controllable crystal size and quantity.

11:40 AM  Cancelled
Optical Properties of Samarium-Doped Oxyfluoride Glasses Containing CaF₂ Nanocrystallites : Marcel Dyrba¹; Paul-Tiberiu Miclea²; Mihail Secu³; Jacqueline Johnson⁴; Stefan Schweizer¹; ¹Martin Luther University of Halle-Wittenberg; ²Fraunhofer Center for Silicon Photovoltaics; ³National Institute of Materials Physics; ⁴University of Tennessee
    In the past two decades samarium fluorescence in glasses has attracted much attention, in particular for studies on spectral-hole burning, excited state absorption, and laser properties. The glass matrix and the specific glass network vibrations, i.e. the phonon frequencies affect the fluorescence efficiency of the embedded samarium ions significantly. Here, Sm³⁺-doped silicate-based glasses were additionally doped with calcium fluoride to allow for a growth of CaF₂ nano-crystallites upon post synthesis thermal processing. The optical properties, in particular the fluorescence efficiency of the Sm³⁺ ions, which are assumed to act as nucleation centers for the CaF₂ nano-cyrstallites, depend significantly on the size of nano-crystallites. The CaF₂ nano-crystallites have lower phonon frequencies and thus enable higher fluorescence efficiencies of the embedded Sm³⁺ ions. The crystallization dynamics and the influence on the fluorescence efficiency of Sm³⁺-containing nano-crystallites were investigated.