Stimulated Brillouin gain spectroscopy in a confined spatio-temporal domain (30 μm, 170 ns) Lionel Djadaojee, Albane Douillet and Jules Grucker Eur. Phys. J. Appl. Phys., 89 3 (2020) 30701 Published online: 12 May 2020 DOI: 10.1051/epjap/2020200012