Abstract
Investigation of thin metallic film properties by means of picosecond ultrasonics has been under the scope of several studies. Generation of longitudinal and shear waves with a wave vector normal to the film free surface has been demonstrated. Such measurements can not provide complete information about properties of anisotropic films. Acute focusing of the laser pump beam (≈ 0.5 µm) on the sample surface has recently allowed us to provide evidence of picosecond acoustic diffraction in thin metallic films (≈1 µm) such as aluminum, gold, copper. Waveforms have been experimentally recorded in a gold layer (2 µm thick) for several distances between pump and probe on the sample surface. Due to acoustic diffraction, the acoustic wavefronts propagate at a group velocity which differs from phase velocity in the anisotropic film. However, a specified signal processing allows us analyzing the space repartition of the acoustic wave-vectors for both longitudinal and shear waves. Four stiffness coefficients of the anisotropic gold layer could thus be recovered accurately, demonstrating the feasibility of the measurement.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
