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Abstract: We show an inorganic–organic hybrid silica gel glass with remarkable femtosecond optical Kerr effect in the order of the time-resolution of the experiment (∼200fs) based on doped lead phthalocyanine. In our materials, self-diffraction of the pumping beam by ultrafast transient gratings dominates the Kerr signal, ensuring ultrafast response happens. By the replacement of inorganic or polymeric matrix with inorganic-organic hybrid, many practical advantages can be gained. Our results demonstrate a critical role for the design of novel ultrafast optical Kerr shutters in such low-cost silica based-nanocomposites with great flexibility. [Copyright &y& Elsevier]

Abstract: Multiphoton-induced two-dimensional periodic microstructures were fabricated in dye-doped bulk transparent materials by four-beam interference of femtosecond pulses at a wavelength of 800nm. Observations of optical microscopy show that two-dimensional microstructures are realized in the samples through nonresonant absorption process. The photoinduced refractive index modulation, resulted from the multiphoton-induced photodecomposition, is responsible for the periodic microstructures. These results suggest that this method can be applied to a wide variety of transparent materials and that the materials co-doped with different dyes and with photoinduced microstructure may be possible to make the distributed feedback lasers with novel properties. [Copyright &y& Elsevier]

Abstract: We report on multiphoton-induced periodic microstructures inside bulk polymers by multibeam interference of femtosecond laser pulses at a wavelength of 800 nm, which is out of the linear absorption range of the polymer sample. Two-dimensional structures and three-dimensional periodic microstructures were fabricated inside bulk azodye-doped polymethylmethacrylate by four-beam interference and five-beam interference, respectively. The Raman spectra measurements for the photomodified area of the sample before and after irradiation with the writing light showed that the periodic microstructures probably arose from photoinduced decomposition reaction of azodye molecules through multiphoton absorption. [Copyright &y& Elsevier]

Azodye-doped vinyl group substituted bulk silica materials were prepared by a sol–gel method. Photoinduced noncentrosymmetry in these initially centrosymmetric rigid matrixes was demonstrated first using nonresonant all-optical poling with a fundamental light at wavelength of 1500 nm and its second-harmonic light. The largest photoinduced second-order nonlinear optical coefficient d33 was estimated to be 8×10−3 pm/V. The characteristic kinetics of decay of the induced second-order susceptibility was measured by second-harmonic generation. Although the signal decay was fast and the coefficient d33 was low, we found that increasing the power of the seeding beams could improve the second-harmonic signal decay process. [Copyright &y& Elsevier]

The photoinduced birefringence induced by a femtosecond laser through two-photon absorption was studied in bulk azodye-doped hybrid inorganic–organic materials. The probe transmittance for the induced birefringence was estimated to be 92% after irradiating disperse red 1-doped silica materials with the femtosecond writing beam. The relaxation characteristic of the induced birefringence was also investigated. Although the signal decay process was fast, these photoinduced birefringence materials might have wide applications in optical image storage. [Copyright &y& Elsevier]

Abstract: Birefringence in azodye-doped polymethylmethacrylate (PMMA) and azodye-doped inorganic–organic hybrid silica was induced by multiphoton excitation of a femtosecond laser. Comparing the growth kinetics of the photoinduced birefringence (PB) in the two matrixes, we concluded the mechanisms of photoinduced anisotropy were different and azodye-PMMA was much better for applications in optical storage. We also found that the growth rate and saturation value of the PB in azodye-PMMA were dominated by either peak or average power of the laser, strongly depended on writing conditions. An optimal control of the PB by varying writing conditions was indispensable to fully realize optical storage. [Copyright &y& Elsevier]