Disentanglement of Multiple Scattering Contribution in Brillouin Microscopy

Due to multiple scattering (MS), Brillouin spectroscopy is currently limited to analyzing transparent materials or the surface of opaque samples. To favor the applications toward in-depth 3D analysis, we provide a new analytic expression and an innovative experimental method to isolate the MS effect. The analytic model, derived from a fundamental description of the interaction process, compares well with a new experimental method, named polarization gated Brillouin spectroscopy, which selects the MS contribution through light polarization. Both experimental and analytic methods are tested against a benchmark material, milk, demonstrating their capability to extract reliable micromechanical parameters even for the in-depth investigation of highly turbid material.