David A. Horsley (Advisor)

Very fast optical beam steering and wave front correction can be achieved by employing phased arrays of lightweight High Contrast Grating (HCG) MEMS mirror etalons. The etalons provide a large phase shift for a small displacement, 100x more than traditional reflective mirror elements. Operating such etalon arrays requires exquisite control of the MEMS mirror displacements. Our aim is to use in-situ stroboscopic interferometric imaging of the etalons to ensure phase accuracy and combat long term-drift, while employing feed-forward electrical input shaping to achieve fast settling time...

We developed an optical phased array incorporating a single-layer high-index-contrast sub- wavelength grating (HCG) for 2D beamsteering. There are a number of other approaches for optical phased arrays such as liquid-crystal-based phased arrays and microelectromechanical system (MEMS) phased array. Switching of liquid-crystal based phased arrays typically takes on the order of milliseconds. Arrays of MEMS mirrors moving perpendicular to the substrate are usually made of silicon so that a metal-coated layer is required on top, resulting in thermal induced stress when very high optical...

Despite their small size, low power dissipation, and low cost, the large bias and scale factor errors of current MEMS inertial sensors preclude using them for dead reckoning navigation. Although these shortcomings can be overcome with precision manufacturing and extensive calibration, such solutions suffer from high cost and secondary effects such as long term drift. Presently, the use of in-situ calibration techniques in MEMS sensors is limited to the electronic interfaces, where they are instrumental for reducing drift arising from electronic components. This project extends the...

We've successfully built a 500dpi, 4.75mm x 3.5mm monolithic ultrasonic fingerprint sensor on a chip with PMUT and integrated CMOS process that solves the problem of capacitive fingerprint sensors. The sensor is resilient to common contamination such as dirt, sweat, and oil by penetrating through them, and the sensor has the capability of capturing inner-finger feature such as dermis fingerprint. The capability of generating a three- dimensional, volumetric image of the finger surface and the tissues beneath the finger surface makes it extremely difficult to deceive the sensor with...