We show that permanent optical waveguides can be formed in various bulk glasses by photoinduced refractive index change with an ultrashort pulse laser. The waveguides were fabricated by focusing the laser beam through an microscope objective and translating the sample parallel to the axis of the laser beam. From the observations of intensity distributions in the output of guided light by a CCD camera, we demonstrated that permanent optical waveguides can be successfully formed in various glasses. In addition, from the analysis of a near-field pattern, it was confirmed that single mode waveguides of the graded index type can be formed by a writing technique using the ultrashort pulse laser.

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Two water-soluble porphyrin self-assemblies consisting of bisacetylene- and monoacetylene-linked conjugated bis(imidazolylporphyrin) have been synthesized. Two-photon absorption (2PA) cross section values in water were determined as 7500 GM for bisacetylene- and 7900 GM for monoacetylene-linked bisporphyrin by femtosecond open-aperture Z-scan measurement. These values were almost the same as those for the similar structure reported previously in CHCl(3). Therefore, the structure is suggested to be similar in CHCl(3) and aqueous solutions. Both compounds were found to efficiently generate singlet oxygen upon one-photon irradiation in a manner similar to protoporphyrin, as demonstrated by the time-resolved luminescence measurement at the characteristic band of 1270 nm. Photocytotoxicities for HeLa cancer cells were examined and found to be as high as those of hematoporphyrin, demonstrating that these newly prepared compounds are potential candidates as 2PA-photodynamic therapy agents.

An ultrafast response of a silver nanoparticle system, as fast as 360 fs, was observed in a femtosecond optical-Kerr-shutter experiment. The ultrafast response is attributed to a self-diffraction of a pump pulse due to transient grating. We estimated χ (3) of the silver nanoparticle system to be 1.5 × 10 −7 esu in the femtosecond region.

Analysis of energy transfer processes in Yb3+-Tb3+ co-doped, low-silica calcium aluminosilicate glasses J. Appl. Phys. 110, 083108 (2011); 10.1063/1.3653272Long-lasting phosphorescence in Sn 2+ -Cu 2+ codoped silicate glass and its high-pressure treatment effect