Detection of shear picosecond acoustic pulses by transient femtosecond polarimetry
LPEC, UMR CNRS 6087, Université du Maine, 72085 Le Mans, France
2 LAUM, UMR CNRS 6613, Université du Maine, 72085 Le Mans, France
Femtosecond transient polarimetry has been applied for the detection picosecond acoustic pulses generated in a thin film of zinc oxide (ZnO) deposited on an anisotropic zinc crystal surface. The measurements of the variations of the azimutal and the ellipticity angles describing the ultrafast variations of the state of polarisation (SOP) of the reflected light have been obtained. These polarimetric signals, interpreted as a SOP path on the Poincaré sphere, provide a sensitive method to detect acoustic echoes, particularly for shear acoustic pulses.
© EDP Sciences, Springer-Verlag, 2008