We report on near-infrared to visible upconversion luminescence in transparent Eu-doped SrO-TiO-SiO glass-cera...
Bin Zhu Songmin Zhang Shifeng Zhou Nan Jiang Jianrong Qiu 1 State Key Laboratory of Silicon Materials,Zhejiang University,Hangzhou 310027,China 2 Department of Physics and Astronomy Arizona State University,Tempe,Arizona 85257-1504,USA
The femtosecond laser induced void array inside Al_2O_3 crystals was discussed.The void array was formed spontaneously under the irradiation of a single beam of infrared femtosecond laser which was focused at a fixed point inside the Al_2O_3 crystal sample.It was found that the regular voids only could be fabricated near the sample surface,which was different from the situation in CaF_2 single crystal reported before. The possible mechanism of the phenomena was also discussed.
We report on a simple and novel method to induce Si-related oxygen-deficient defects in CaO-Al_2O_3-SiO_2 glasses by using Al metal instead of part Al_2O_3.Blue emission is observed from the glass samples.Moreover,the quantities of the oxygen-deficient defects can be controlled by adjusting Al content. We also prepare glass samples using Al instead of part Al_2O_3 and doped with Eu^(3+) ions.Addition of Al results in reduction of Eu^(3+) ions to Eu^(2+) ions and change of the luminescence property.The investigation made on to control and characterize the defects could lead to the development of more efficient economical materials with improved properties.
In Ag^+ and Au^(3+) co-doped silicate glass sample,we realized controllable precipitation and dissolution of Ag and Au nanoparticles.A new method was proposed for separate precipitation of Ag and Au nanoparticles in different areas of the same sample through femtosecond laser irradiation and further annealing;different colors were obtained in the same glass.We also studied the laser dissolution of Ag and Au nanoparticles in the Ag^+ and Au^(3+) co-doped silicate glass.The mechanism of the phenomena we observed was discussed briefly.
Infrared to visible upconversion luminescence was demonstrated in trivalent Europium doped Ca_2Al_2SiO_7 crystal (Eu^(3+):Ca_2Al_2SiO_7) irradiated by focused infrared femtosecond laser.The upconversion luminescence originated from ~5D_0 to ~7F_j (j=1,2) transitions of Eu^(3+).The relationship between the upconversion luminescence intensity and the pump power indicated that the upconversion from near-infrared to red is dominated by a two-photon absorption process of Eu^(3+).Analysis suggested that two-photon simultaneous absorption induced population inversion should be the predominant frequency upconversion mechanism.
