Minquan Wang

Temperature-dependent luminescent properties of Eu–Tb complexes synthesized in situ in gel glass

The chelates of europium and terbium with hexafluoroacetylacetone (HFA) and triphenylphoshine oxide (TPPO), Eu∕Tb(HFA)3(TPPO)2, have been synthesized in situ in gel glasses with various concentrations of Eu3+ and Tb3+ ions. The photoluminescence spectra have been measured and the characteristic transitions of Tb3+ and Eu3+ have been observed. Due to the variance of energy transfer efficiencies from Tb3+ to Eu3+, the intensity ratios of europium luminescent band to terbium band vary remarkably with measurement temperatures. In addition, the Forster mechanism has been proved to be responsible for the energy transfer between Eu3+ and Tb3+. The materials doped with Eu∕Tb(HFA)3(TPPO)2 are promising for being used as a temperature detector and thermal-sensitive probe of optical fiber sensor.

Photoinduced birefringence of azodye-doped materials by a femtosecond laser

Birefringence in azodye-doped polymethylmethacrylate and azodye-doped silica hybrid materials was induced by the two-photon excitation of a femtosecond laser. The growth and the relaxation characteristics of the photoinduced birefringence in the two types of material were investigated, and the probe transmittance for the induced birefringence was estimated to be 92%. Furthermore, an optical image storage based on this photoinduced birefringence was demonstrated.

Holographic volume gratings in bulk perylene-orange-doped hybrid inorganic-organic materials by the coherent field of a femtosecond laser

Holographic volume gratings with high first-order Bragg diffraction efficiency (greater than 35%) were fabricated in bulk laser-dye-doped hybrid inorganic-organic materials by the coherent fields of a femtosecond laser. Observations of optical microscopy show that refractive-index-modulated volume gratings were realized inside the sample through multiphoton absorption process. The isomerization and alignment of the laser dye molecules are responsible for the grating formation. We suggest that the materials codoped with laser dye and azodye and with photoinduced gratings inside are promising materials for making the distributed feedback tunable lasers.