Full-field Brillouin microscopy based on an imaging Fourier transform spectrometer

Abstract: Brillouin microscopy is an emerging optical elastography technique that can be used to assess mechanical properties of biological samples in a 3D, all-optical and hence non-contact fashion. However, the low cross-section of spontaneous Brillouin scattering results in weak signals typically requiring prolonged exposure times or illumination dosages potentially harmful for biological samples. Here, we present a new approach for highly-multiplexed, and therefore rapid, spectral acquisition of the Brillouin scattered light. Specifically, by exploiting a custom-built Fourier-transform imaging spectrometer and the symmetric properties of the Brillouin spectrum, we experimentally demonstrate full-field 2D spectral Brillouin imaging of phantoms as well as biological samples, at a throughput of up to 40,000 spectra per second over a ~300um field-of-view. This represents an approximately three orders of magnitude improvement in speed and throughput compared to standard confocal methods while retaining high spatial resolution and the capability to acquire three-dimensional images of photosensitive samples in biology and medicine.