Wave propagation and properties in negative index media

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Negative index media (NIM), also known as left-handed media (LHM) or double negative media (DNG), have not been found in nature.   Artificial materials, called metamaterials, have been created to demonstrate the existence of negative refraction; i.e., a negative index of refraction.  This project studies wave propagation and other properties involved with negative index media.   In a negative index medium, the phase velocity is opposite to the direction of propagation (the Poynting vector direction).  Thus, the vector triad of electric field, magnetic field, and k vector, which is a right-handed triad in ordinary media, becomes a left-handed triad in negative index media; hence, the term left-handed media was coined by the Russian, Veselago.

Because of the left-handedness of this material, several interesting wave properties can be exploited for applications ranging from antenna design to optics, transmission lines, and sensors.  The figure below shows how the center of a beam wave packet refracts negatively in accordance with Snell’s law at the interface of free space with a NIM.  However, the shape and orientation of the ellipsoidal packet changes in a more complicated way.  The possibility of high-resolution focusing by a planar layer is another interesting property which we have explored in considerable detail.



Wave packet propagation onto the interface of free space and NIM



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Sponsored by NSF