Enhancement of plasmonic coupling on Si metallized with intense femtosecond laser pulses.

Using a pump-probe technique, the reflectivity of a silicon grating surface irradiated with intense femtosecond (fs) laser pulses was measured as a function of the incidence angle and the delay time between pulses. After irradiating the surface with an intense s-polarized, 400 nm, 300 fs laser pulse, the reflectivity measured with a weak p-polarized, 800 nm, 100 fs laser pulse exhibited an abrupt decrease for an incidence angle of ~ 24°. The depth of the dip was greatest for a delay time of 0.

Potential generation of nano-sized mist by passing a solution through dielectric barrier discharge.

Plasma medicine, a therapeutic technology that uses atmospheric-pressure plasma, is attracting much attention as an innovative tool for the medical field. Most of the plasma biomedical tools use direct effects, such as heat, optical stimulation, and reactive chemical species, on the lesion. Nanoparticulation techniques using indirect action by plasma, i.

Fabrication of Periodic Nanostructures on Silicon Suboxide Films with Plasmonic Near-Field Ablation Induced by Low-Fluence Femtosecond Laser Pulses.

Silicon suboxide (SiO, ≈ 1) is a substoichiometric silicon oxide with a large refractive index and optical absorption coefficient that oxidizes to silica (SiO) by annealing in air at ~1000 °C. We demonstrate that nanostructures with a groove period of 200-330 nm can be formed in air on a silicon suboxide film with 800 nm, 100 fs, and 10 Hz laser pulses at a fluence an order of magnitude lower than that needed for glass materials such as fused silica and borosilicate glass. Experimental results show that high-density electrons can be produced with low-fluence femtosecond laser pulses, and plasmonic near-fields are subsequently excited to create nanostructures on the surface because silicon suboxide has a larger optical absorption coefficient than glass.

Nanostructure Formation on Diamond-Like Carbon Films Induced with Few-Cycle Laser Pulses at Low Fluence from a Ti:Sapphire Laser Oscillator.

This study reports the results of experiments on periodic nanostructure formation on diamond-like carbon (DLC) films induced with 800 nm, 7-femtosecond (fs) laser pulses at low fluence from a Ti:sapphire laser oscillator. It was demonstrated that 7-fs laser pulses with a high power density of 0.8⁻2 TW/cm² at a low fluence of 5⁻12 mJ/cm² can form a periodic nanostructure with a period of 60⁻80 nm on DLC films.

Fabrication of 50-nm period gratings on GaN in air through plasmonic near-field ablation induced by ultraviolet femtosecond laser pulses.

We demonstrate the formation of a homogeneous nanograting with 50-nm period on GaN in air, using ultraviolet femtosecond (fs) laser pulses at 266 nm in the recently developed two-step ablation technique. The experimental results have shown that the ablation technique successfully controlled the spatial mode of surface plasmon polaritons (SPP) excited on the target surface and decreased the grating period in accordance with the short wavelength of fs laser pulses. Calculation for a model target reproduces well the laser-wavelength dependent periods, being in good agreement with the observed, and supports the mechanism for nanostructuring.