The optical and physical properties of a low-voltage phosphor, SrGa2S4:Eu2+, are reviewed. This phosphor has excellent chromaticity and high luminous efficiency at excitation voltages <3 kV and at high drive current (∼100 μA/cm2). At high current densities this phosphor was found to have superior saturation properties compared to current phosphors. This is attributed to the fast decay time of this phosphor, which is expected to enhance its resistance to saturation. Recent studies show that this phosphor has good maintenance properties.

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We present a spectroscopic overview of Cr +-doped Y3A150» (YAG), a new laser material for the near-infrared region (NIR). It is found that only 2% of the Cr ions are tetrahedrally coordinated Cr +.However, the optical spectra are dominated by this ion. The missing inversion symmetry for the tetrahedral site causes higher cross sections than are common for octahedrally coordinated ions. The experimental data include a survey of the absorption and emission features. Lifetime measurements, as well as piezospectroscopic experiments yield additional spectroscopic information. Our data suggest an energy-level assignment that is different from the one previously used to describe the spectrum. Instead of ascribing the strong NIR absorption band, centered at around 1000 nm, to the '8&('A2) 'E('T2) transition, we assign it to the '8&('A&)~'A2('T&) transition. This assignment is able to describe the polarization-dependent spectra, the piezospectroscopic results, and the results from earlier polarizationdependent saturation experiments.An analysis of the luminescence decay rate yields quantum eSciencies of around 49% at 10 K and 15% at room temperature, resulting in a peak emission cross section of 3.5X10 19 cm2

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