Elastic suppression in Brillouin imaging by destructive interference

Brillouin microscopy is an emerging technique to yield high spatial resolution mechanical images in a non-contact manner. The main challenge in Brillouin spectroscopy is given by the detection and the localisation of the Brillouin peaks, in particular, when a high amount of elastic light is collected. We demonstrate a purely interferometric method to suppress the parasitic light which overwhelms the Brillouin spectrum using destructive interference in a Michelson interferometer. A suppression ratio of 35dB is readily achieved. Both double and single stage virtually imaged phased array spectrometers are tested showing that the Brillouin peaks can still be measured when the intensity of the elastic light is higher by 53dB, hence, enabling 3D mechanical imaging of thin biological systems such as cells.