XERIDAT , Olivier

Elastic waves propagating in thin plates are an efficient tool for the fundamental study of waves in complex media. They allow developing experimental setups of macroscopic size, broadband and non-invasive when the generation and detection of ultrasounds are performed by laser. The experimental tool developed in this thesis allows direct access...

We report non-invasive measurements of the complex field of elastic quasimodes of a silicon wafer with chaotic shape. The amplitude and phase spatial distribution of the flexural modes are directly obtained by Fourier transform of time measurements. We investigate the crossover from real mode to complex-valued quasimode, when absorption is...