High-rejection birefringent filter for Brillouin mechanical imaging in turbid media

Non-contact Brillouin microscopy holds potential to become an essential tool for mechanobiology, yet this method faces challenges in turbid samples as a consequence of strong Rayleigh scattering. Here, we introduce a common-path birefringence-induced phase delay (BIPD) filter exhibiting an extinction ratio of 65 dB in a single-pass configuration. We demonstrate the capability of the filter to acquire Brillouin maps in turbid samples such as bone tissues of a mouse model of osteopetrosis, a rare genetic disorder with generalized increase in bone density.