MRI: Development of an Angle-Dispersive Brillouin Imaging Spectrometer

技术摘要布里渊光谱学是一种非弹性光散射技术，它允许精确测量材料内部的高频纵向和横向声速。声速和声衰减的测定进一步允许测定块体的机械性能，包括弹性、体积模数、劳道-普拉切克比、折射率和泊松比。从历史上看，液体和固体材料的扫描法布里-珀罗涉仪布里渊光谱非常难以测量，并且需要在实验期间保持湿度和温度的稳定性，这可能需要几个小时。这是它默默无闻，而其他类型的弹性测量，如超声波和应力应变技术占主导地位的原因之一。我们的团队计划通过创造一种更快、更容易使用的布里渊光谱仪来使布里渊光谱学成为一种更实用的光谱学，它允许同时使用显微镜和成像技术。最近的研究表明，光学技术的进步可以用来设计一种简单易用的快速收集角色散型法布里-珀罗涉仪。角度色散共焦布里渊仪的设计将允许在几毫秒到几秒内获得大多数材料的声学特性。本课题组建议开发一种基于角度色散型法布里-珀罗涉仪的布里渊光谱仪，该光谱仪具有显微镜和成像能力。这一拟议的仪器将是此类仪器中的第一台，并将为新类型的原位非破坏性机械测量和机械对比成像打开大门。非技术摘要目前用于确定材料的机械性能的许多方法都会导致原始材料的破坏。然而，布里渊光谱学方法可以用来以非破坏性的方式测量材料的‘硬度’和弹性。它以其发现者马塞尔·布里渊的名字命名，是揭示与材料相关的动力学和机械性质的最强大的方法之一。布里渊光谱学直接测量激光照射在固体或液体样品上的频移(类似于使用频移测量速度的警察雷达)。这使得可以确定许多机械性能，包括弹性(刚性)、体积弹性(可压缩性)和折射率。J.L.Yarger的研究小组最近开发了一种用于布里渊光谱的角度色散法布里-珀罗涉仪(ADFPI)。我们建议使用最近设计的ADFPI作为构建共焦布里渊显微镜和成像系统的基础，以扩展可用于表征材料的力学和弹性性质的成像和光谱技术。

Technical AbstractBrillouin spectroscopy is an inelastic light scattering technique that allows for accurate measurement of high frequency longitudinal and transverse sound velocities within materials. Determination of sound velocity and acoustic attenuation further permits the determination of bulk mechanical properties including the elasticity, the bulk modulus, the Laudau-Placzek ratio, refractive index, and the Poisson's ratio. Historically, scanning Fabry-Perot Interferometer Brillouin spectroscopy of liquid and solid materials has been very difficult to measure and has required humidity and temperature stability for the duration of the experiment, which can be many hours. This is the one reason for its obscurity and the dominance of other types of elastic measurements such as ultrasonics and stress-strain techniques. Our group plans to make Brillouin spectroscopy a more utilized spectroscopy by creating a much faster and easier to use Brillouin spectrometer that allows performance of both microscopy and imaging techniques. It has recently been shown that advents in optical technologies can be used to design an easy-to-use and fast collecting angle dispersion type Fabry-Perot interferometer. The design of an angle-dispersive confocal Brillouin instrument will allow the acoustic properties of most materials to be obtained in a few milliseconds to seconds. Our group proposes to develop an angle dispersion type Fabry-Perot interferometer based Brillouin spectrometer with microscopy and imaging capabilities. This proposed instrument will be the first of its kind and will open the doors to new types of in-situ non-destructive mechanic measurements and mechanical contrast imaging. Non-Technical AbstractMany of the methods currently used to determine the mechanical properties of a material result in destruction of the original material. Brillouin spectroscopy methods can, however, be used to gauge both the 'hardness' of a material as well as the elasticity in a nondestructive manner. Named after its discoverer, Marcel Brillouin, it is among the most powerful methods of revealing the dynamical and mechanical properties associated with materials. Brillouin spectroscopy directly measures the frequency shift in laser light impinging on a solid or liquid sample (similar to police radar that use a frequency shift to measure speed). This allows the determination of many mechanical properties including the elasticity (stiffness), the bulk modulus (compressibility) and refractive index. J.L. Yarger's research group has recently developed an angle-dispersive Fabry-Perot interferometer (ADFPI) for use in Brillouin spectroscopy. We propose using the recently designed ADFPI as the bases for constructing a confocal Brillouin microscopy and imaging system to extend the imaging and spectroscopy techniques available for characterization of the mechanical and elastic properties of materials.