Impulsive Brillouin microscopy

Brillouin scattering has been emerging as a viable tool for microscopy. However, most of the work done has been with the use of spontaneous Brillouin scattering, which has several hindrances to its use. In this work, we propose and demonstrate nonlinear Brillouin scattering as a solution to many of these hindrances. Here we demonstrate fast two-dimensional microscopic optical imaging of materials’ mechanical properties for the very first time (to our knowledge) using nonlinear Brillouin scattering. Impulsive stimulated Brillouin scattering (ISBS) was used in an optical configuration that is capable of providing accurate local assessment of viscoelastic properties faster than conventional Brillouin spectroscopy. This proof-of-principle imaging experiment has been demonstrated for materials of known properties and microfluidic devices. Applications to noninvasive biomedical imaging are discussed. The fast acquisition times and strong signal of ISBS coupled with the ability of Brillouin scattering to easily measure materials’ viscoelastic properties make this an attractive technique for biological use.