Samarium doped zinc-phosphate glasses having composition Sm 2 O 3 (x) ZnO (60Àx) P 2 O 5 (40) (where x ¼ 0.1-0.5 mol%) were prepared by melt quenching method. The density of these glasses was measured by Archimedes method; the corresponding molar volumes have also been calculated. The values of density range from 3.34 to 3.87 gm/cm 3 and those of molar volume range from 27.62 to 31.80 cm À3. The optical absorbance studies were carried out on these glasses to measure their energy band gaps. The absorption spectra of these glasses were recorded in UV-visible region. No sharp edges were found in the optical spectra, which verifies the amorphous nature of these glasses. The optical band gap energies for these glasses were found to be in the range of 2.89-4.20 eV. The refractive index and polarizability of oxide ion have been calculated by using Lorentz-Lorentz relations. The values of refractive index range from 2.13 to 2.42 and those of polarizability of oxide ion range from 6.51 Â 10 À24 to 7.80 Â 10 À24 cm 3 .

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Glasses with the composition, (Sm 2 O 3) x (ZnO) (40-x) (TeO 2) (60), were prepared by conventional melt quenching method. The density, molar volume, and optical energy band gap of these glasses have been measured. The refractive index, molar refraction and polarizability of oxide ion have been calculated by using Lorentz-Lorentz relations. Optical absorption spectra of these glasses were recorded in the range 300-700 nm at room temperature. The oxide ion polarizabilities deduced from two different quantities, viz. refractive index and optical energy band gap, agree well compared with other glasses. The nonlinear variation of the above optical parameters with respect to samarium dopant has been explained.

a b s t r a c tSpherical and rod like nanocrystalline Nd 2 O 3 phosphors have been prepared by solution combustion and hydrothermal methods respectively. The Powder X-ray diffraction (PXRD) results confirm that hexagonal A-type Nd 2 O 3 has been obtained with calcination at 900 • C for 3 h and the lattice parameters have been evaluated by Rietveld refinement. Surface morphology of Nd 2 O 3 phosphors show the formation of nanorods in hydrothermal synthesis whereas spherical particles in combustion method. TEM results also confirm the same. Raman studies show major peaks, which are assigned, to F g and combination of A g + E g modes. The PL spectrum shows a series of emission bands at ∼326-373 nm (UV), 421-485 nm (blue), 529-542 nm (green) and 622 nm (red). The UV, blue, green and red emission in the PL spectrum indicates that Nd 2 O 3 nanocrystals are promising for high performance materials and white light emitting diodes (LEDs).

Structural and optical properties of antimony-containing sodium borate glasses were studied and their ultrafast third-order nonlinear optical (NLO) properties have been evaluated using Z-scan measurements with femtosecond (fs) pulses (∼150 fs, 80 MHz) at 750, 800, and 880 nm wavelengths. Glasses in the (mol %) 20Na 2 O−(80 − x)B 2 O 3 −xSb 2 O 3 (where x = 0, 10, 20, and 30) system have been fabricated via melt quench technique. The structural modifications were analyzed using the Raman and magic angle spinning (MAS)-nuclear magnetic resonance (NMR) ( 11 B MAS-NMR and 23 Na MAS-NMR) techniques. The optical absorption spectra revealed that the absorption edge was red-shifted, suggesting the decrease in band gap energy with increase of antimony content in the glasses. Raman scattering results revealed that the boroxol rings are depressed with the incorporation of Sb 2 O 3 for replacing B 2 O 3 . 11 B MAS-NMR results showed a progressive increase of B 4 units at the expense of B 3 units. The Raman and 11 B MAS-NMR results support the formation of Sb 5+ ions due to oxidation of Sb 3+ that played the role of charge compensation. 23 Na MAS-NMR spectra revealed a decreasing trend in the average of bond lengths of Na−O with increasing Sb 2 O 3 contents. This suggested that sodium changed its role from charge compensator to modifier cation. The antimony-containing glasses demonstrated a reverse saturable absorption in open-aperture Z-scan mode due to two-photon absorption, while closed-aperture Z-scan signatures depicted positive nonlinear refraction due to self-focusing effect. The NLO coefficients were found to increase with Sb 2 O 3 due to the increased nonbridging oxygens and also due to the hyperpolarizability of Sb 3+ and Sb 5+ ions. The observed NLO data clearly suggest that the investigated glasses are beneficial for optical limiting applications.