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- ItemDynamical studies on the generation of periodic surface structures by femtosecond laser pulses(Les Ulis : EDP Sciences, 2013) Rosenfeld, A.; Höhm, S.; Bonse, J.; Krüger, J.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.
- ItemNonlinear optical mechanism of forming periodical nanostructures in large bandgap dielectrics(Les Ulis : EDP Sciences, 2013) Grunwald, R.; Das, S.K.; Debroy, A.; McGlynn, E.; Messaoudi, H.Nonlinear excitation mechanisms of plasmons and their influence on femtosecond-laser induced sub-wavelength ripple generation on dielectric and semiconducting transparent materials are discussed. The agreement of theoretical and experimental data indicates the relevance of the model.
- ItemAdaptive micro axicons for laser applications(Les Ulis : EDP Sciences, 2015) Wallrabe, Ulrike; Brunne, Jens; Treffer, Alexander; Grunwald, Ruediger; Bellouard, YvesWe report on the design, fabrication and testing of novel types of low-dispersion axicons for the adaptive shaping of ultrashort laser pulses. An overview is given on the basic geometries and operating principles of our purely reflective adaptive MEMS-type devices based on thermal or piezoelectric actuation. The flexible formation of nondiffracting beams at pulse durations down to a few oscillations of the optical field enables new applications in optical communication, pulse diagnostics, laser-matter interaction and particle manipulation. As an example, we show first promising results of adaptive autocorrelation. The combination of excellent pulse transfer, self-reconstruction properties and propagation invariance of nondiffracting beams with an adaptive approach promises to extend the field of practical applications significantly.
- ItemTransition from ballistic to drift motion in high-field transport in GaAs(Les Ulis : EDP Sciences, 2013) Bowlan, P.; Kuehn, W.; Reimann, K.; Woerner, M.; Elsaesser, T.; Hey, R.; Flytzanis, C.With strong THz pulses, we measure ultrafast transport of electrons, holes, and an electron-hole plasma in GaAs. The transition from ballistic to drift-like transport is strongly influenced by electron-hole scattering.
- ItemUltrafast multi-electron dynamics studied with THz-field streaking(Les Ulis : EDP Sciences, 2018) Krikunova, M.; Klimešová, E.; Kulyk, O.; Oelze, T.; Schütte, B.; Gebert, T.; Andreasson, J.; Silaev, A.A.This article has no abstract.