Diffusion of Particles and Photons in Complex Fluids

w：\awards\awards96\*.doc 9623441 Yodh 这个凝聚态物理学的实验研究项目将研究胶体悬浮液中的粒子动力学 以及在高度散射或混浊介质中扩散光子动力学。 这些对胶体的研究围绕着控制胶体粒子运动的新思路。 特别是，陷阱和模板， 将通过仔细构造自由能势垒来产生衬底上的粒子。这些自由能垒是由于悬浮液中的熵效应而产生的。 光子输运的研究将集中在高度散射光的基本性质上。特别是，研究将 研究材料的各向异性和波动 被施加在光子电磁场上，该光子电磁场以类似于热流的方式扩散通过混浊介质。 对光束进入高度散射或混浊材料的仔细研究揭示了各种有趣的现象和应用。光以类似于热流的方式在这些物质中扩散。由于我们对这些过程的了解越来越多，漫射光现在可以用来生成人体组织和其他复杂的不透明介质中吸收或散射变化的低分辨率图像。 这项建议的一个目标是发展一个更好的基本了解这些过程，并进一步开发所需的仪器来利用这些现象，使更多样化的应用是可能的。该提案的第二个目标是创建基于粒子悬浮的新材料，其可能用于光子学的局部领域。 ***

w:\awards\awards96\*.doc 9623441 Yodh This experimental research project in condensed matter physics will study particle dynamics in colloidal suspensions and diffusing photon dynamics in highly scattering or turbid media. These studies of colloids center around new ideas for the control of colloidal particle motion. In particular, traps and templates for particles on substrates will be created by carefully constructing free energy barriers. These free energy barriers are brought about as a result of entropy effects in the suspension. Photon transport investigations will center on the fundamental properties of highly scattered light. In particular the research will study how material anisotropy, and fluctuations are impressed upon photon electromagnetic fields that diffuse through turbid media in a manner similar to heat flow. %%% Careful study of light beams passing into highly scattering or turbid materials has revealed a variety of interesting phenomena and applications. Light diffuses through these substances in a manner similar to heat flow. As a result of our increased knowledge about these processes diffusing light can now be used to generate low resolution images of absorption or scattering variations within human tissues and in other complex, opaque media. One goal of this proposal is to develop an improved fundamental understanding of these processes, and to further develop the instrumentation required to exploit these phenomena, so that more diverse applications are possible. A secondary goal of this proposal is to create new materials based on particle suspension that may be of use in the topical field of photonics. ***