Ultrafast changes in the optical properties of a titanium surface and femtosecond laser writing of one-dimensional quasi-periodic nanogratings of its relief

Journal Article · Fri Jul 15 00:00:00 EDT 2011 · Journal of Experimental and Theoretical Physics

DOI:https://doi.org/10.1134/S1063776111050025· OSTI ID:22028064

Golosov, E V ^[1]; Ionin, A A ^[2]; Kolobov, Yu R ^[1]; Ligachev, A E ^[3]; Novoselov, Yu N; Seleznev, L V; Sinitsyn, D V ^[2]

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1. Belgorod State University (Russian Federation)
2. Russian Academy of Sciences, Lebedev Physics Institute (Russian Federation)
3. Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)

One-dimensional quasi-periodic nanogratings with spacings in the range from 160 to 600 nm are written on a dry or wet titanium surface exposed to linearly polarized femtosecond IR and UV laser pulses with different surface energy densities. The topological properties of the obtained surface nanostructures are studied by scanning electron microscopy. Despite the observation of many harmonics of the one-dimensional surface relief in its Fourier spectra, a weak decreasing dependence of the first-harmonic wavenumber (nanograting spacing) on the laser fluence is found. Studies of the instantaneous optical characteristics of the material during laser irradiation by measuring the reflection of laser pump pulses and their simulation based on the Drude model taking into account the dominant interband absorption allowed us to estimate the length of the excited surface electromagnetic (plasmon-polariton) wave for different excitation conditions. This wavelength is quantitatively consistent with the corresponding nanograting spacings of the first harmonic of the relief of the dry and wet titanium surfaces. It is shown that the dependence of the first-harmonic nanograting spacing on the laser fluence is determined by a change in the instantaneous optical characteristics of the material and the saturation of the interband absorption along with the increasing role of intraband transitions. Three new methods are proposed for writing separate subwave surface nanogratings or their sets by femtosecond laser pulses using the near-threshold nanostructuring, the forced adjustment of the optical characteristics of the material or selecting the spectral range of laser radiation, and also by selecting an adjacent dielectric.

• OSTI ID: 22028064
• Journal Information: Journal of Experimental and Theoretical Physics, Vol. 113, Issue 1; Other Information: Copyright (c) 2011 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7761
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
77 NANOSCIENCE AND NANOTECHNOLOGY
ABSORPTION
COMPUTERIZED SIMULATION
DIELECTRIC MATERIALS
EXCITATION
HARMONICS
LASER RADIATION
NANOSTRUCTURES
ONE-DIMENSIONAL CALCULATIONS
OPTICAL PROPERTIES
PERIODICITY
PULSES
REFLECTION
SCANNING ELECTRON MICROSCOPY
SURFACE ENERGY
SURFACES
TITANIUM