Pump-probe Reflectivity Studies of Ultrashort Laser-induced Acoustic Strains in Layered Materials

Funded by: Hellenic Foundation for Research and Innovation H.F.R.I.

Summary: In the framework of the program, elastic waves are produced and detected in layered metal/substrate materials using ultrashort femtosecond laser pulses with a wavelength λ=800 nm. Through the acoustic waves induced by the laser radiation, it is possible to study the elasto-mechanical characteristics of the materials under study. For this purpose, an experimental pump-probe device has been developed, based on the pump-probe transient reflectivity technique. The studied samples have a metal coating a few tens of nm thick. The metal coating (Au, Ti, Ta, etc.) plays the role of the optoacoustic transducer, i.e. the transducer of optical energy into mechanical deformation and propagating elastic waves. Examples of materials that have been studied in the context of the program are ZnO with Au coating, silicon Si with Ta coating, Titanium Ti etc. with thicknesses from a few tens to hundreds of nm. At the same time, a theoretical thermomechanical model has been developed based on the modified Two Temperature Model (TTM) to verify and support the experimental results.

Members of the research team: Kyriaki Kosma Principal Investigator, Evaggelos Kaselouris Postdoctoral Researcher, Konstantinos Kaleris Postdoctoral Researcher

Advisory Committee: Nektarios Papadogiannis Professor, Vasilios Dimitriou Associate Professor, Efthimios Bakarezos Professor, Michalis Tatarakis Professor