Improvement of gain and spatial resolution for impulsive stimulated Brillouin scattering microscopy.

Brillouin microscopy has been widely used in the mechanical imaging of cells and tissues, and the signal-to-noise (SNR) ratio limits the spectral integration time. Impulsive stimulated Brillouin scattering (ISBS) microscopy is a new elastic imaging technique. As a variant of stimulated Brillouin scattering (SBS), ISBS can overcome the weak signal of spontaneous Brillouin scattering. A simple model can estimate SBS gain. However, the theoretical ISBS gain has not been compared with SBS gain. This paper gives the theoretical ISBS gain estimation, and experiments are designed to verify estimation reliability. The heterodyne ISBS gain coefficient can be much higher than SBS gain coefficient. The relationship between ISBS gain coefficient and spatial resolution is then discussed. We anticipate that the ISBS setup optimization can improve spatial resolution and gain, potentially enabling fast and high spatial resolution imaging of biological cells.