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Physics

In studying physics, asking very simple questions often puts one at the forefront of current research and, indeed, opens whole new research areas. The field of metamaterials was developed over the last decade by posing fundamentally simple queries: can light refract negatively? What are the basic limits on the wavelength of light inside materials? What would happen if different components of the electric field vector in a light beam experienced a radically different electromagnetic environment?

This last question lies at the heart of my Ph.D. thesis (pdf). Although simple to state, it presents a fundamental theoretical problem that can have a profound impact in applications.

Ordinarily, the world of applied physics is rife with trade-offs. Indeed, many are codified in the fundamental laws, such as the Heisenberg uncertainty principle. Yet most limitations are mere caprices of Nature, which tailors material parameters to its fickle, oft-inscrutable specifications, making a mockery of theoretical device designs. Metamaterials offer a tantalizing escape from this status quo. By custom-designing material properties, we can strike down some of the vexing compromises that limit performance and capabilities of optical devices.

Many of the trade-offs in nanophotonics involve the fundamental differences between metals and dielectrics. These differences make metals appealing for some applications (e.g. short-wavelength waveguides, or emission enhancement), but quite unappealing for others. Dielectrics suffer from a similar fate. Can we create a material that would behave both like a metals and a dielectric? The answer is yes. Such materials are called hyperbolic, and they can be fabricated using modern metamaterials techniques. Some rare examples of hyperbolic materials can even be found in nature!

The following video (done in the style popularized by Sal Khan, Sebastian Thrun, and Andrew Ng) provides a (mostly) non-technical explanation of my work: 5+ years of research described in 5 minutes.