This PDF file contains the front matter associated with SPIE Proceedings Volume 8609, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

Self-assembled monolayers of thioether substituted subphthalocyanine [BClSubpc(Sn-C₁₂H₂₅)₆] were prepared by deposition from solution. The adsorption kinetics of the molecules on gold substrates was characterized in situ and in real time by optical second harmonic generation (SHG). The obtained data have been fitted with three standard kinetic models and best agreement has been found using the first order Langmuir kinetic model. Subsequently, ellipsometry measurements have been performed to determine the thickness of the formed molecular layers. The extracted thickness was 13.0 nm, demonstrating the formation of a monolayer.

Laser-induced periodic surface structures, also known as ripples, have been investigated for a long time on various materials. They are self-organized grating-like structures that form spontaneously upon irradiation with a single laser beam; their formation requiring a high temperature rise, it generally results from interactions with ultrashort laser pulses. Recently, similar phenomena leading to periodic changes in the morphology of metallic nanoparticles embedded in polymer films have been reported under femtosecond laser exposure. Here, we demonstrate that chain-like self-organized silver nanoparticles can be grown, from an ionic silver precursor, within titania films under continuous wave visible laser beam. The nanoparticle chains are periodically spaced with a period that depends on the wavelength and are oriented parallel to the laser polarization. The samples present no significant surface modulation since all of the grown nanoparticles are located at the substrate-film interface, protected by a crystallized TiO₂ film. SEM, TEM, HRTEM and EDX characterizations of the film nanostructuring are shown. Due to the coupling of incident light to a guided mode of the TiO₂ film by the first diffraction order of the NP grating, such samples exhibit a strong dichroism whose characteristics depend on the laser exposure conditions. Color changes and spectral variations with polarization are measured and interpreted. The high stability of such colored films under high temperature rises or high intensity UV or visible exposures is demonstrated; it makes them good candidates for colored data storage.

Titanium dioxide (TiO₂) has a variety of functions, but cannot be activated by visible-light illumination. It is importance to extend the activity of TiO₂ into the visible-light, which comprises the larger portion of the room light. Therefore, the visible-light activated TiO₂ is required. We developed it with the femtosecond laser irradiation. The TiO₂ films irradiated with femtosecond laser were darkened without changing topography of the TiO₂ film surface. In the visible-light photocataltic function measurements, the TiO₂ films were evaluated with the acetaldehyde decomposition test. The concentration of acetaldehyde was decreased to over time. This result indicated that visible-light activated photocatalyst function of TiO₂ films were generated by femtosecond laser irradiation.

We have previously reported the observation of self-organized tungsten nanogratings during chemical vapor deposition of tungsten induced by a 400-nm 80-MHz laser oscillator on a wide range of substrates. We show that the growth of nanostructures begins with a thin tungsten film, followed by a rapid formation of periodic texture, when the laser power exceeds a threshold value. The threshold power is found strongly substrate dependent. The ubiquitous presence of thin films prior to nanograting growth suggests adatom diffusion induced by laser heating is vital, as the strong electronphonon coupling in tungsten is expected to turn absorbed photon energy rapidly into heat. Using a simplified 1D heat diffusion model, we estimate the critical surface temperature on various substrates at the onset of nanograting formation, based on substrate-specific threshold power and material properties. We found interesting correlation of critical temperatures: all the covalent substrates (AlN, Al₂O₃, quartz, silica, and glass) exhibit a common critical temperature while the ionic substrates (MgO, MgF₂, and CaF₂) share another yet different critical temperature. The critical temperature of covalent substrates is found higher than that of ionic substrates, indicating the former possesses larger activation energy for adatom diffusion. Based on this model, we can also extract a substrate-independent enthalpy for nanograting formation. Although the present 1D model overestimates the surface temperature, the correlation of critical temperatures among substrates and the presence of a unique enthalpy independent of substrates strongly support the role of laser heating and adatom diffusion in the formation of tungsten nanogratings.

Periodic nanostructures formation on Titanium dioxide (TiO₂) film by scanning of femtosecond laser beam spot at fundamental and second harmonic wave is reported. Titanium (Ti) is one of the most widely used for biomaterials, because of its excellent anti-corrosion and high mechanical properties. However, Ti implant is typically artificial materials and has no biofunction. Hence, it is necessary for improving the bioactivity of Ti. Recently, coating of TiO₂ film on Ti plate surface is useful methods to improve biocompatibility of Ti plate. Then, if periodic nanostructures were formed on the film surface, cell spreading might be controlled at one direction. We propose periodic nanostructures formation on TiO₂ film by femtosecond laser irradiation. Cell spread could be controlled along the grooves of periodic nanostructures. In the experiments, the film was formed on Ti plate with an aerosol beam. A commercial femtosecond Ti : sapphire laser system was employed in our experiments. Periodic nanostructures, lying perpendicular to the laser electric field polarization vector, were formed on the film at fundamental and second harmonic wave. Periodic nanostructures were also produced on Ti plate with femtosecond laser. The period of periodic nanostructures on the film was much shorter than that on Ti plate. By cell test, there was a region of cell spreading along the grooves of periodic nanostructures on the film formed with femtosecond laser at fundamental wave. On bare film surface, cell spreading was observed at all direction. These results suggest that direction of cell spread could be controlled by periodic nanostructures formation on the film.

Laser processing 3-D microstructures inside KDP crystals is an effective way to suppress the transverse stimulated ramam scattering（TSRS）in high power lasers. A simulation study on the transmission characteristics of focused laser inside KDP crystal was carried out to investigate the feasibility of laser processing 3-D microstructures and the effects of laser parameters on the machining accuracy, efficiency and yield. The effects of the peak power density, spot distortion and deviation of laser focus are the main factors on the machining accuracy and crystal fragmentation. The size and shape of the e-ray focus will distort and its peak power density decreases rapidly with the increasing of angle between incident laser and crystal optical axis. The results show that the effect of the e-ray will make the processing efficiency increase more than double when the angle is less than 15°, and can be neglected in the low-energy or easily causes crystal fragmentation in high-energy when the angle is greater than 30°, in this case the e-ray should be shielded. The related simulated results have an important engineering value on increasing the accuracy of laser micromachining birefringent materials.