Intense green luminescence in Mn-doped gallogermanate nanostructured glass

Mn activated optical materials have been demonstrated to be promising for various applications such as light-emitting device, tunable lasers and smart sensors. Most of the candidates belong to the single crystals and crystalline powders and few reports involve about the glass-derived materials. In this letter, we report the fabrication of active Mn-doped nanostructured glass sample via control of the crystallization of a typical gallogermanate glass. LiGa5O8 and LiGaGeO4 can precipitate after heat-treatment and Mn centers selectively incorporate into the crystalline phase. Importantly, the luminescence can be switched from red to green color and the intensity can be simultaneously enhanced. Furthermore, the luminescence properties can be tuned via control of the phase of the nanostructured glass. The approach should be general to various transition metal dopant, thus may potentially pave an effective way for functionalization of glass and expand the category of the active optical materials.

Высокотемпературная диффузия акцепторной примеси Ве в AlN

The high-temperature diffusion of an acceptor impurity of beryllium (Be) into bulk single-crystal aluminum nitride (AlN) has been studied. It is shown that the introduction of Be leads to the appearance of green luminescence of AlN, which is stable at room temperature and is observed over the entire thickness of the sample. It was shown by the method of luminescence analysis that the Be diffusion process is most efficiently realized in the temperature range from 1800°C to 2100°C and is characterized by extremely high diffusion coefficients D = 10-7 cm2/s and 10-6 cm2/s, respectively. It is shown that a prolonged diffusion process (t ≥ 1 hour) at a temperature of 2100°C leads to concentration quenching of the luminescence of near-surface AlN layers with a thickness of ≈ 80 μm, which makes it possible to estimate the concentration of beryllium impurities in the near-surface layer on the order of 10E19 cm-3.

Synthesis, crystal structures and spectroscopic properties of pure YSb2O4Br and YSb2O4Cl as well as Eu3+- and Tb3+-doped samples

The oxygen atoms of the two new compounds belong to ψ1-tetrahedral [SbO3]3− units, which are either vertex-connected to four-membered rings in YSb2O4Cl or to endless chains in YSb2O4Br. Eu3+- and Tb3+-doped samples show red or green luminescence.

Erbium energy bridging upconversion mechanism studies on BAKL: Er3+/Yb3+ glass-ceramics and simultaneous enhancement of color purity of the green luminescence

Borate oxyfluoride glasses are transparent in the infra-red, ultra violet and visible regions and represent an ideal host matrix for optically active dopants. Due to their lower phonon energies compared...

Nonlinear imaging of whispering gallery modes in GaN microwires

In this work non-scanning far-field nonlinear optical microscopy is employed to study the whispering gallery modes in tapered GaN microwire resonators. We demonstrate the confinement of whispering gallery modes under near-infrared excitation with the photon energy close to half of GaN bandgap. Our results indicate the enhancement of yellow-green luminescence by whispering gallery modes in GaN microwires.