Ultrafast Nonlinear Scattering and Deflection of Femtosecond Laser Pulses

Abstract

Ultrafast processes in physics, chemistry, biology and material science are already investigated by time-resolved spectroscopy since picosecond (ps) and femtosecond (fs) laser sources became available [1]. Different interaction processes during the excitation and the relaxation of the illuminated matter were studied. The contribution due to the interaction of the photons with electrons, phonons, plasmons or other types of matter excitation can be separated with respect to the specific temporal and spectral characteristics [2].

In our experiments we used the time-resolved scattering and deflection of a light beam to investigate different excitation and decay processes. Scattering due to coherent electronic excitation and deflection due to coherent and incoherent phonon excitation on a time scale of 100 fs to 50 ps were studied. This is to our knowledge the first time where the transition from the electronic light scattering to the photothermal beam deflection is investigated.