Improved absorbance of holmium activated magnesium-zinc-sulfophosphate glass

Constant efforts are dedicated to overcome the limitations of phosphate based glass system, where sulfophosphate glasses (SPGs) played a key role. Rare earth ions (REIs) doped magnesium zinc SPG (MZSPG) systems are technologically prospective due to their several unique attributes. Construction of integrated light amplifier and solid state laser needs the maximum gain within small component dimensions. Thus, Ho3+ ions doped SPGs are believed to meet this demand. Ho3+ ions having sharp optical absorption peaks in the spectral range of 200–900 nm is useful for diversified applications. Conversely, SPGs comprising of oxides of sulphur, phosphorous and at least one other component with SO42- ions contents lower than PO43- with low melting temperature makes them a distinctive class of technologically potential disordered system. In this view, modification of Ho3+ ions absorbance inside SPGs network is challenging. To achieve this goal, following melt-quenching route we prepared a series of Ho3+-doped MZSPG system of composition (60-x)P2O5-(20)ZnSO4-(20)MgO–(x)Ho2O3, where x = 0.0, 0.5, 1.0, 1.5 2.0, and 2.5 mol%. The influence of Ho2O3 concentration on the density, refractive index, and optical absorption properties of the synthesized glass system is examined. The density and refractive index is found to increase with increasing Ho2O3 concentration. The absorption spectra revealed nine prominent peaks centered at 387, 418, 450, 484, 538, 642, 1148 and 1945 nm. The glass absorbance is enhanced with increasing Ho3+ contents. Optical band gap energy is found to range from 3.847 to 3.901 eV. The reduction of Urbach energy from 0.257 to 0.191 eV with increasing Ho3+ contents verified the shrinkage of glass network structure and lowering of defect mediated disorder. In-depth investigations on the structural and optical properties of MZSPG system are underway to achieve the milestones set for photonic devices.

Green-emitting Lu3Al5O12:Ce3+ phosphor as a visible light amplifier for dye-sensitized solar cells

A down convertor Lu3Al5O12:Ce3+ (LuAG) phosphor was used as a visible light amplifier for dye-sensitized solar cells (DSSCs).

The Quest for “Magnalux”

In September 1951, Radio Corporation of America chairman David Sarnoff celebrated his 45th year in the electronics industry by publicly challenging his research staff to develop three new technologies in time for his golden anniversary dinner 5 years later. This article considers the fate of one of these items, the “Magnalux” light amplifier, to explore how scientists, manufacturing personnel, and managers viewed the significance of fundamental research to technological innovation. Following a discussion of the content and context of Sarnoff’s request, the article focuses on the creation of two prototype light amplifiers to emphasize the contingency of technological success and failure and the centrality of commercial considerations in defining those categories. This case study reaffirms the value of historical methodologies to the social study of corporate science.