The transformation design method and metamaterials: tools to realize invisibility cloaks and other i

David SchurigMing Hsieh
Department of Electrical EngineeringSEMINAR
"The transformation design method and metamaterials: tools to realize invisibility cloaks and other interesting devices"Abstract:
I will explain how the transformation design method works. One begins this design process by imagining a fictitious space with an interesting or useful property, for example, a hole for hiding things, or a "dense" region that concentrates energy. I will explain how such fictitious spaces can be described mathematically by a coordinate transformation. Then I will explain how the theories of such coordinate transformations and the form invariance of Maxwell's equations leads directly to a material specification. This material specification can implement the electromagnetic properties of the interesting fictitious spaces in the boring, approximately "flat", three dimensional spaces in which we live.
We have used this method to design invisibility cloaks, but the method is quite general and can be used to design a wide variety of interesting devices that guide, concentrate or shape electromagnetic fields in ways that would be difficult to manage with other design methodologies. Applications range from stealth to energy conversion and distribution to wireless communications to biomedical imaging.
The drawback of the method is the complexity of the material specifications that it produces, which have particular anisotropy (variation with angle) and inhomogeneity (variation with position). Only with recent advances in the field of metamaterials can these specifications be realized. I will discuss how metamaterials accomplish this and what their limitations are, e.g. bandwidth, absorption, frequency range etc.
I will discuss in detail the recent implementation of an invisibility cloak in the microwave spectrum. Unlike, traditional stealth, an invisibility cloak reduces both reflection and shadow. Thus both these ways of detecting an object, (the reflection of electromagnetic waves incident on the front of an object and the blocking of electromagnetic waves originating from behind the object) are weakened. If such a cloak were implemented for visible light (a daunting task), then when one looked at the cloaked object one would see the scene behind it.Biography:
David Schurig received his BS in Engineering Physics from U.C. Berkeley, and then worked at Lawrence Berkeley Lab on laser ablation and photoacoustic spectroscopy. He attended physics graduate school at U.C. San Diego and received a PhD in 2002 for his thesis on negative index media, the perfect lens and related structures. David also worked for the California Space Institute, performing space mission feasibility studies, and for Tristan Technologies, designing and building, cryogenically cooled, SQUID-based instruments. David is now a post doctoral fellow at Duke University. He is designing invisibility cloaks and other interesting devices using the transformation method and implementing them with metamaterials.

Location: Hedco Neurosciences Building (HNB) - 100

Audiences: Everyone Is Invited

Contact: Ericka Lieberknecht