Speaker

Chenjun Shi, Wayne State University

Abstract

Brillouin microscopy, which is based on spontaneous Brillouin scattering, provides a non-invasive method for quantifying the mechanical properties of biological materials with diffraction-limited resolution. Since the scattering efficiency of the spontaneous Brillouin is very small, high laser power and ultrasensitive detection are usually required to collect the weak Brillouin signal. Recently, several approaches have been proposed to enhance the Brillouin signal, including continuous-wave stimulated Brillouin microscopy, impulsive Brillouin scattering setup, and line-scan Brillouin microscopy.

In this work, we report a new approach to enhance the signal of Brillouin microscopy by simply recycling the power of the illumination beam. This is based on the fact that the majority of the illumination photons do not contribute to the Brillouin signal but propagate away from the sample. To recycle the non-scattered light, we designed a multipass illumination geometry that allows the beam to pass through the sample through the same path multiple times (as many as four). By doing this, we obtained about 3.75 times enhancement of the Brillouin signal compared to single-path illumination under the same input power. Here, we presented the detailed optical design of the setup and demonstrated the signal enhancement with different path numbers by using water as the sample. As a next step, we will study how this idea can be adapted to the biomedical application.

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In-person location: Biomedical Engineering, room 2220 (Map)