Tomographic reconstruction of picosecond acoustic strain pulses using automated angle-scan probing with visible light

Motonobu Tomoda; Hiroyuki Matsuo; Osamu Matsuda; Roberto Li Voti; Oliver B Wright

doi:10.1016/j.pacs.2023.100567

Tomographic reconstruction of picosecond acoustic strain pulses using automated angle-scan probing with visible light

Photoacoustics. 2023 Oct 29:34:100567. doi: 10.1016/j.pacs.2023.100567. eCollection 2023 Dec.

Authors

Motonobu Tomoda¹, Hiroyuki Matsuo¹, Osamu Matsuda¹, Roberto Li Voti², Oliver B Wright^{3

4}

Affiliations

¹ Faculty of Engineering, Hokkaido University, Sapporo, 060-8628, Japan.
² Department SBAI, Sapienza University of Roma, Via A. Scarpa 14, Roma, I-00161, Italy.
³ Hokkaido University, Sapporo, 060-0808, Japan.
⁴ Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan.

Abstract

By means of an ultrafast optical technique, picosecond acoustic strain pulses in a transparent medium are tomographically visualized at GHz frequencies. The strain distribution in BK7 glass is reconstructed from time-domain reflectivity changes of 415-nm probe light as a function of the optical incidence angle with 1 ps temporal and 120 nm spatial resolutions, enabled by automated angle scanning. The latter resolution is achieved owing to the commensurate acoustic wavelength. Applications include imaging strain, carrier and temperature distributions on ultrashort timescales.

Keywords: Acoustic tomography; Angle scan; Brillouin scattering; Inverse problem; Picosecond ultrasonics; Singular value decomposition.