Time-domain Brillouin scattering (TDBS) is an experimental technique for generation and detection of nanometers-in-length acoustic pulses using ultrafast lasers, which was originally referred to as picosecond acoustic interferometry [1]. Experimental signals collected with the TDBS technique in transparent materials contain Brillouin oscillations, caused by interference of the probe laser pulses reflected from stationary interfaces and from the propagating ultrashort acoustic pulses. Frequencies of the Brillouin oscillations depend on the local refractive index and the local longitudinal sound velocity. Therefore, accurate estimates in a TDBS signal of the Brillouin frequency with respect to time give an access to the variations of the material parameters as a function of material depth. TDBS experiments could give access to acoustical, optical and acousto-optical parameters of the materials [2], by carrying experiments at several incidence angles for instance. Some applications of the TDBS technique for depth profiling of polycrystalline materials under very high-pressures [3,4] as well as its ability for real-time imaging of phase transition [5] will be presented. Limitations of this imaging technique, as well as the perspectives of its extension in multiple research areas [6] and industrial fields, will also be discussed. References [1]C. Thomsen, H. T. Graham, H. J. Maris, J. Tauc, Optics Communications 60, 55 (1986). [2]A. M. Lomonosov, A. Ayouch, P. Ruello, G. Vaudel, M. R. Baklanov, P. Verdonck, L. Zhao, V. E. Gusev, ACS Nano 6, 1410 (2012). [3]M. Kuriakose, S. Raetz, N. Chigarev, S. M. Nikitin, A. Bulou, D. Gasteau, V. Tournat, B. Castagnede, A. Zerr, and V. E. Gusev, Ultrasonics 69, 259-267 (2016). [4]M. Kuriakose, S. Raetz, Q. M. Hu, S. M. Nikitin, N. Chigarev, V. Tournat, A. Bulou, A. Lomonosov, P. Djemia, V. E. Gusev, and A. Zerr, Phys. Rev. B 96, 134122 (2017). [5]M. Kuriakose, N. Chigarev, S. Raetz, A. Bulou, V. Tournat, A. Zerr, and V. E. Gusev, New J. Phys., 19, 053026 (2017). [6]V. E. Gusev, P. Ruello, Appl. Phys. Rev. 5, 031101 (2018).