Surface plasmon Sagnac interferometry for label-free characterization of flows in microfluidic environments

该计划的目标是开发一种无标记的基于表面等离子体的光学传感器，该传感器依赖于称为光子拖曳的相对论效应来表征微米级流体流动。智力的优点是表面等离子体Sagnac干涉仪，这将使光学映射的低对比度流在纳米和微流体通道，使用相敏检测的拟议发展。一个流体循环的光流控池将被集成到干涉仪中，并将测量由光子拖曳在池中激发的反向传播等离子体上产生的相移。理论建模将伴随实验研究。与现有的基于振幅敏感表面等离子体激元的设备相比，这种干涉测量方法允许将检测阈值降低一个数量级。这种增强对于芯片上气体和单分子传感、纳米级流速诊断和微射流流体装置监测至关重要。该提案的变革性方面在于开发利用表面等离子体干涉测量法绘制微米级流动条件的新方法。这对于开发用于芯片实验室系统的无标签微流体传感器具有潜在的变革性，能够快速，非交互和准确地诊断局部流场。更广泛的技术影响是通过开发能够诊断微观流体流动以及检测微湍流和电流的等离子体传感器对未来传感技术的影响。更广泛的教育影响包括学生培训，学生将获得等离子体传感和微流体制造和操作技术方面的宝贵专业知识。学生的专业发展也通过参与外联活动来解决，从而促进更广泛社区的科学素养的发展。

The objective of this program is to develop a label-free, surface plasmon-based optical sensor which relies on a relativistic effect known as photon drag to characterize micron-scale fluid flows. The intellectual merit is the proposed development of a surface-plasmon Sagnac interferometer, which will enable optical mapping of low-contrast flows in nano- and microfluidic channels, using phase-sensitive detection. A fluid-circulating opto-fluidic cell will be integrated into the interferometer, and the phase shifts resulting from photon drag on counter-propagating plasmons excited in the cell will be measured. Theoretical modeling will accompany the experimental studies. Compared to existing amplitude-sensitive surface plasmon-based devices, this interferometric method allows lowering of the detection threshold by an order of magnitude. Such enhancement is crucial for on-chip gas and single molecule sensing, nano-scale flow-rate diagnostics, and micro-jet fluidic device monitoring. The transformative aspect of the proposal lies in the development of new methods for mapping micron-scale flow conditions using surface plasmon interferometry. This is potentially transformative for the development of label-free microfluidic sensors for lab-on-chip systems, enabling rapid, non-interacting and accurate diagnostics of local flow fields. The technological broader impacts are on future sensing technologies, through the development of plasmonic sensors able to diagnose microscopic fluid flows, as well as detect microturblence and electrical currents. The educational broader impacts include student training students will acquire valuable expertise in plasmonic sensing and microfluidic fabrication and operation techniques. Students professional development is also addressed through participation in outreach activities, thus facilitating the development of science literacy in the broader community.