Optical excitation and detection of terahertz acoustic waves with semiconductor superlattices
Résumé
Experimental results about light-to-sound transduction with semiconductor superlattices are presented. Picosecond ultrasonics with pump and probe incident on opposite sides of the substrate allows a full decoupling between generation and detection processes. Associating a metallic transducer, we show that superlattices generate quasi-monochromatic wave packets which can propagate over macroscopic distances in the underlying substrate but are also very selective and sensitive detectors. At the end, using two superlattices simultaneously as phonons generator and detector we evidence that these new transducers allow to perform acoustic experiments at the challenging frequency of 1THz.