基于虚像相位阵列共焦布里渊光谱技术的弹性模量测量

Elastic modulus measurement based on virtual image phase array confocal Brillouin spectroscopy technology

生物组织和材料的弹性模量是决定其力学性能的关键因素,对生物医学和材料监测等领域至关重要。提出了一种基于虚像相位阵列的弹性模量测量方法,虚像相位阵列与共聚焦显微系统相结合,能够快速获得生物组织和材料的布里渊光谱频移,从而计算得到其弹性模量。首先,理论上分析了材料的弹性模量和布里渊光谱频移之间的关系;然后,介绍了虚像相位阵列的原理及系统的各组成部分;最后,对样品材料进行光谱测试,分别测得了聚乙烯、二氧化硅玻璃和聚甲基丙烯酸甲酯(PMMA)的光谱,求得纵向弹性模量M分别为7.23 GPa、83.4 GPa和8.92 GPa,并且测得了PMMA的布里渊光谱图像。结果表明:虚像相位阵列与衍射光栅级联使用,能够改善标准具的级次重叠现象,提高布里渊光谱的分辨率和采集速率,该系统设计的激光和背向散色光抑制模块,显著提高了布里渊信号的对比度,在材料特性、结构监测和生物医学等方面具有重要意义。

The elastic modulus of biological tissues and materials is the key factor to determine their mechanical properties, which is very important for biomedicine and material monitoring. A method for measuring elastic modulus based on virtual image phase array was proposed. Combining virtual image phase array with confocal microscopy system, the Brillouin spectrum frequency shift of biological tissues and materials could be obtained quickly, and then the elastic modulus could be calculated. Firstly, the relationship between the elastic modulus and Brillouin spectrum frequency shift was analyzed theoretically;Then, the principle of the virtual image phase array and the components of the system were introduced;Finally, the spectrum test of the sample material was performed, and the spectra of polyethylene, silica glass, and polymethyl methacrylate(PMMA) were measured,the longitudinal elastic modulus M was calculated to be 7.23 GPa, 83.4 GPa and 8.92 GPa, respectively, and the Brillouin spectral image of PMMA was measured. The results show that the cascade use of the virtual image phase array and the diffraction grating can improve the order overlap phenomenon of the etalon, and increase the resolution and acquisition rate of the Brillouin spectrum. The laser and backscattering light suppression module designed by this system can significantly improve the contrast of the Brillouin signal which is of great significance in material properties, structure monitoring and biomedicine.