Spectral analysis of amplitude and phase echoes in picosecond ultrasonics for strain pulse shape determination

Takehiro Tachizaki; Jeremy J Baumberg; Osamu Matsuda; Motonobu Tomoda; Hirotsugu Ogi; Oliver B Wright

doi:10.1016/j.pacs.2023.100566

Spectral analysis of amplitude and phase echoes in picosecond ultrasonics for strain pulse shape determination

Photoacoustics. 2023 Oct 29:34:100566. doi: 10.1016/j.pacs.2023.100566. eCollection 2023 Dec.

Authors

Takehiro Tachizaki¹, Jeremy J Baumberg², Osamu Matsuda³, Motonobu Tomoda³, Hirotsugu Ogi⁴, Oliver B Wright^{4

5}

Affiliations

¹ School of Information Science and Technology, Tokai University, Hiratsuka, Kanagawa, 259-1292, Japan.
² NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, United Kingdom.
³ Faculty of Engineering, Hokkaido University, Sapporo, 060-8628, Japan.
⁴ Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan.
⁵ Hokkaido University, Sapporo, 060-0808, Japan.

Abstract

We introduce a spectral analysis method in picosecond ultrasonics to derive strain pulse shapes in a opaque sample with known optical properties. The method makes use of both the amplitude and phase of optical transient relative reflectance changes obtained, for example, by interferometry. We demonstrate this method through numerical simulation and by analysis of experimental results for a chromium film.

Keywords: Optical interferometry; Photoelastic effect; Picosecond ultrasonics; Strain pulse; Ultrafast.