A High Resolution Evanescent Wave Velocity Sensor for Liquid and Gas Flow in Microfluidics

This project proposes to design and build an advanced evanescent velocity sensor for near wall velocity measurements in microfluidic devices. Optical MEMS technology will be utilized to create a compact sensor design. The sensor will measure velocities within 100 nm of the channel wall, which is five times closer than the best current technique. The sensor will have a spatial resolution of 100 nm, which is twenty times better than the best current technique. The sensor will use evanescent wave illumination to perform Nano Particle Image Velocimetry (nPIV). During Phase I, an evanescent wave sensor prototype will be designed and fabricated using optical MEMS technology. The prototype will be tested in a liquid microchannel flow. In addition, feasibility studies will be conducted on both optimizing nPIV and extending the sensor's capabilities into: three-dimensional nPIV, gas phase velocimetry and, sensing spatially and temporally resolved fluid temperatures. Initial testing will use liquid flows; subsequent testing will be in gas flow regimes. During Phase II, a sensor commercially viable for a variety of applications, including three-dimensional nPIV, thermometry, and gas phase applications will be fabricated.