Work

Depth profiling of temperature in water at a micrometer scale using time resolved Brillouin scattering

Year: 2024

Type: article

Abstract: Picosecond ultrasonics is a technique where coherent acoustic phonons are generated with frequencies in the GHz frequency range. When optical detection is operated in a transparent medium, the interaction of these phonons with the probe pulses yields oscillations in the time domain that reveal Brillouin scattering. Their frequency is at the Brillouin frequency shift, commensurate with the phonon velocity. As the pump–probe experiments are time-resolved, changes in the Brillouin frequency with time can be attributed to changes in sound velocity with depth. As sound velocity is temperature-dependent in liquids, we show that the picosecond ultrasonics technique can be used for temperature depth profiling in liquids. In this work, the concept is proved using the pump absorption itself as a heat source and confronting measured changes in Brillouin frequency with depth with data resulting from the derivation of a 3D modeling of the temperature rise in the liquid. We demonstrate the remote depth profiling of temperature, with measured data spaced at a distance less than the optical wavelength.

Source: Journal of Applied Physics

DOI: 10.1063/5.0225134

Authors: Zouhir Maslah, Bertrand Audoin

Institutions: Centre National de la Recherche Scientifique, Université de Bordeaux, Institut de Mécanique et d'Ingénierie de Bordeaux

Language: English

Topic: Optical and Acousto-Optic Technologies

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,500

Funder: Centre National de la Recherche Scientifique