Coaxial line-scanning Brillouin microscopy

Abstract

Confocal Brillouin microscopy (CBM) enables high-resolution mechanical imaging but has slow acquisition speeds due to its point-by-point scanning strategy. Line-scanning Brillouin microscopy (LSBM) offers imaging acquisition speed improvements but faces challenges such as beam distortion in biaxial configurations and insufficient extinction ratio due to the single-stage VIPA spectrometer. To overcome these limitations, we developed a coaxial line-scanning Brillouin microscopy (cLSBM) system by using a two-stage parallel VIPA spectrometer. The coaxial design minimizes image distortion, and the two-stage parallel VIPA spectrometer significantly enhances the rejection of non-Brillouin noises. Experiment results showed that the first VIPA, served as a filter for noise rejection, has a rejection ability of 18 dB. The system was characterized by standard materials including ethanol and water, achieving a precision of 7.5 MHz and 12.6 MHz respectively. In the next step, we will optimize the system to further enhance noise rejection and utilize this setup to investigate the evolution of tissue mechanics during embryonic development.