We use a variety of techniques to probe nano-scale interactions including atomic force microscopy, nearfield scanning microscopy, and traditional optical microscopy. Additionally, we are interested in developing new tools and techniques to better understand these interactions.
Energy is one of the most important issues of our day, and its impact can be felt in politics, environmental discussions, and in science and technology. We are working on projects that combine interesting physics and engineering with technologies for tomorrow’s energy production needs. Specifically, we are exploring photonic and plasmonic nanostructures for both traditional photovoltaic solar cells as well as antenna based energy harvesting.
The fields of plasmonics, metamaterials, and metasurfaces offer new opportunities for molding the flow of light at the nanoscale, enabling high field concentrations and increased light-matter interactions. However, metals are often involved and result in significant optical loss. Here we turn this loss into an opportunity by exploiting the short lived carrier excitation upon absorption, so-called hot carriers. New ultra-fast, detectors and energy converts can be constructed based on this phenomenon.
Just as wind can exert a pressure on a sail to propel a sailboat, light too can exert a pressure on a reflective object. This radiation pressure can be used to propel small spacecrafts and is the working principle behind solar sails. We are working to develop thin film optical metamaterials, composed of sub-wavelength resonant structures, which are capable of changing, in real-time, the optical properties of the device locally to allow for active control of the photon pressure, and hence the ability to steer, without the need for mechanically movable parts. In addition, we aim to probe the true nature of photon momentum in dielectric media—a controversy dating back to the early 1900s.
The Casimir force is a quantum mechanical phenomenon that results in an attractive force between two uncharged parallel conducting plates in vacuum. We have found ways to manipulate the boundaries between materials in order to change this force in nontrivial ways. Examples of this include a “QED toque” between birefringent materials and a “Repulsive Casimir force” between two materials due to their dielectric properties. Experiments like these should pave the way for engineering the quantum vacuum.