Publications

Mobile sensor networks present opportunities for improved in situ sensing in complex hydrodynamic environments such as estuarial deltas. This dissertation considers the design and implementation of the mobile sensor network system that was built as part of the Floating Sensor Network project for use in the Sacramento-San Joaquin Delta in California over the 2007-2012 time period. Individual Lagrangian sensor units collect hydrodynamic state information, which is then transmitted to a centralized server and assimilated to produce a state estimate for the entire hydrodynamic system....

Over the past few decades, semiconductor lasers have relentlessly followed the path towards miniaturization. Smaller lasers are more energy efficient, are cheaper to make, and open up new applications in sensing and displays, among many other things. Yet, up until recently, there was a fundamental problem with making lasers smaller: purely semiconductor lasers couldn't be made smaller than the diffraction limit of light.

In recent years, however, metal-based lasers have been demonstrated in the nanoscale that have shattered the diffraction limit. As optical materials, metals can be...

High quality factor (Q) optical whispering gallery mode resonators are a key component in many on-chip optical systems, such as delay lines, modulators, and add-drop filters. They are also a convenient, compact structure for studying optomechanical interactions on-chip. In all these applications, optical Q is an important factor for high performance. For optomechanical reference oscillators in particular, high mechanical Q is also necessary. Previously, optical microresonators have been made in a wide variety of materials, but it has proven challenging to demonstrate high optical Q and...

Cavity Optomechanical oscillators (OMOs) rely on photon radiation pressure to induce harmonic mechanical motion of a micron-scale light resonator. Unlike most oscillators, optomechanical oscillators require only CW input light without the need for electronic feedback and so hold promise for their novelty. In an optical cavity of sufficient quality factor, the transduction from photons to phonons can be quite efficient as we characterized optomechanical cavities which only required 17 microwatt input optical power to induce mechanical oscillation. The question then remains whether OMOs can...