Dynamical studies on the generation of periodic surface structures by femtosecond laser pulses

The dynamics of the formation of laser-induced periodic surface structures (LIPSS) on fused silica upon irradiation with linearly polarized fs-laser pulses (50 fs pulse duration, 800 nm center wavelength) is studied experimentally using a double pulse experiment with cross polarized pulse sequences and a trans illumination femtosecond time-resolved (0.1 ps - 1 ns) pump-probe diffraction approach. The results in both experiments confirm the importance of the ultrafast energy deposition and the laser-induced free-electron plasma in the conduction band of the solids for the formation of LIPSS

Dynamical studies on the generation of periodic surface structures by femtosecond laser pulses

The dynamics of the formation of laser-induced periodic surface structures (LIPSS) on fused silica upon irradiation with linearly polarized fs-laser pulses (50 fs pulse duration, 800 nm center wavelength) is studied experimentally using a double pulse experiment with cross polarized pulse sequences and a trans illumination femtosecond time-resolved (0.1 ps – 1 ns) pump-probe diffraction approach. The results in both experiments confirm the importance of the ultrafast energy deposition and the laser-induced free-electron plasma in the conduction band of the solids for the formation of LIPSS

Dynamical studies on the generation of periodic surface structures by femtosecond laser pulses

The dynamics of the formation of laser-induced periodic surface structures (LIPSS) on fused silica upon irradiation with linearly polarized fs-laser pulses (50 fs pulse duration, 800 nm center wavelength) is studied experimentally using a double pulse experiment with cross polarized pulse sequences and a trans illumination femtosecond time-resolved (0.1 ps – 1 ns) pump-probe diffraction approach. The results in both experiments confirm the importance of the ultrafast energy deposition and the laser-induced free-electron plasma in the conduction band of the solids for the formation of LIPSS

Dynamical studies on the generation of periodic surface structures by femtosecond laser pulses

The dynamics of the formation of laser-induced periodic surface structures (LIPSS) on fused silica upon irradiation with linearly polarized fs-laser pulses (50 fs pulse duration, 800 nm center wavelength) is studied experimentally using a double pulse experiment with cross polarized pulse sequences and a trans illumination femtosecond time-resolved (0.1 ps – 1 ns) pump-probe diffraction approach. The results in both experiments confirm the importance of the ultrafast energy deposition and the laser-induced free-electron plasma in the conduction band of the solids for the formation of LIPSS

Numerical Analysis of LIPSS Coverage of Silicon Upon Irradiation with Multiple Double-fs-Pulse Sequences: The Impact of Carriers and Cumulative Effects

International audienceThe formation of laser-induced periodic surface structures (LIPSS, ripples) upon irradiation of Silicon with multiple irradiation sequences consisting of femtosecond laser pulse pairs (pulse duration 150 fs, central wavelength 800 nm) is studied numerically using a rate equation system along with a two-temperature model accounting for one and two-photon absorption and subsequent carrier diffusion and recombination processes [1]. The temporal delay between the individual equal energy fs-laser pulses was varied between 0 and 5 ps for quantification of the transient carrier densities in the conduction band of the laser-excited silicon. Additionally, cumulative effects were considered to account for multiple irradiation sequences. The results of the numerical analyses reveal the importance of carrier generation and relaxation processes in fs-LIPSS formation and quantitatively explain the two time constants of the delay dependent decrease of the LSFL area observed experimentally [2]. Evidence is presented that a threshold carrier density must be exceeded transiently to trigger the fs-LIPSS formation on Silicon. [1] T.J.-Y. Derrien, T.E. Itina, R. Torres, T. Sarnet, M. Sentis, Opt. Express, submitted (2013) [2] S. Höhm, A. Rosenfeld, J. Krüger, J. Bonse, Appl. Surf. Sci., doi: http://dx.doi.org/10.1016/j.apsusc.2012.10.188, in press (2013