Abstract

Sub-picosecond Kerr ellipsometry technics is a powerfull tool for non-linear spectroscopy. It allows to observe the evolution, after excitation, of the real and imaginary part of molecules in solution and then to get informations about the photophysical properties of the sample under excitation [1,2]. This technics, which will be discussed, allows to get better signal to noise ratio than time resolved "pump-probe" experiments. It is then possible to work at low excitation energy and low concentrations, avoiding intensity and concentrations effects which may appear in "pump probe" experiments where higher excitation intensity or concentrations are often required to obtain reliable results. Such intensity and concentration effects have been .previously observed in 4-dimcthylamino 4′-cyanostilbene (DCS) and DCS bridged derivatives [3]. In this paper we show that sub-picosecond Kerr ellipsometry allows to study the photophysical behaviour of these derivatives, free from intensity and concentration effects.

© 1996 IEEE