Time-domain Brillouin imaging of sound velocity and refractive index using automated angle scanning

Motonobu Tomoda; Akihisa Kubota; Osamu Matsuda; Yoshihiro Sugawara; Oliver B Wright

doi:10.1016/j.pacs.2023.100486

Time-domain Brillouin imaging of sound velocity and refractive index using automated angle scanning

Photoacoustics. 2023 Apr 11:31:100486. doi: 10.1016/j.pacs.2023.100486. eCollection 2023 Jun.

Authors

Motonobu Tomoda¹, Akihisa Kubota¹, Osamu Matsuda¹, Yoshihiro Sugawara², Oliver B Wright^{3

4}

Affiliations

¹ Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan.
² Analysis Technology Center, FUJIFILM Corporation, Kanagawa 250-0193, Japan.
³ Hokkaido University, Sapporo 060-0808, Japan.
⁴ Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871, Japan.

Abstract

We present a picosecond optoacoustic technique for mapping both the longitudinal sound velocity v and the refractive index n in solids by automated measurement at multiple probe incidence angles in time-domain Brillouin scattering. Using a fused silica sample with a deposited titanium film as an optoacoustic transducer, we map v and n in the depth direction. Applications include the imaging of sound velocity and refractive index distributions in three dimensions in inhomogeneous samples such as biological cells.

Keywords: Brillouin scattering; Picosecond ultrasonics; Refractive index; Sound velocity; Time domain; Ultrafast.