Hypersonic processing in porous materials

The rapidly developing field of nanoacoustics focuses on the study of loudspeaker, which are sound waves ranging from gigahertz to terahertz, at the nanoscale. These high-frequency sound vibrations, also known as acoustic phonons, have the potential to revolutionize various industries, including materials science, medical imaging, data processing, and quantum technologies.

For example, the strong interaction between acoustic phonons, light, and electrons in matter at the nanoscale presents an important opportunity for advances in optoelectronics. However, manipulating loudness has been difficult, in part because of the expensive methods required to fabricate high-quality devices with flat atomic interfaces that can trap these waves.

A team of researchers at the Center for Nanosciences and Nanotechnologies – C2N (CNRS, Université Paris-Saclay) led by Dr. Daniel Lanzelotti Kimura and Dr. Gallo Soler Elia (Instituto de NanoSistemas, Universidad Nacional de San Martin, Argentina), has addressed this challenge in an experimental work published in the magazine optical Using porous thin films to treat hypersonics. Silica- and titania-based mesoporous materials have a regular pattern of pores with sizes about ten thousand times smaller than the diameter of a human hair, and rely on affordable manufacturing methods.

In this study, the researchers made porous thin films using the sol-gel process. They then used ultrafast laser spectroscopy to generate, detect, and study the properties of the confined phonons. “The amazing element about this work is that although the pore sizes are comparable to acoustic wavelengths, thin films with medium pores are still able to withstand acoustic vibrations,” said Daniel Lanzelotti Kimura.

The study has far-reaching implications, and the researchers are now exploring potential applications of their findings. Specifically, porous materials are susceptible to infiltration of liquids and gases, which alter their optical and acoustic properties. “Our next step is to investigate the liquid seepage capacity of porous materials for use in practical applications, such as sensing,” said Edson Cardozo de Oliveira, lead author of the published work.

“We believe that this research will lead to the development of new and innovative technologies that will have a significant impact on various industries.” The team’s findings are a major contribution to the field of nanoacoustics, and the research could pave the way for exciting developments in the future.