UNSW Colloquia 2005

Colloquia 2005

Electrodynamics of Left-Handed Medium

A. L. Efros
1Department of Physics, University of Utah,
Salt Lake City, UT, 84112, USA

Date

4-5 p.m., Thursday, 13 October, 2005 .

Location

School of Physics Common Room
Room 64 Old Main Building
The University of New South Wales

Abstract (Keywords: left-handed materials, negative refraction).
About 40 years ago Veselago [1] considered theoretically propagation of the electromagnetic waves in a hypothetical medium, called Left-Handed Medium (LHM) where both electric permittivity e and magnetic permeability µ are negative in some frequency range. Since the speed of light c² =c₀²/ e µ is positive, the electromagnetic waves propagate but they have unusual properties, like anomalous Doppler and Cherenkov effects and negative refraction at the interface with a regular medium. The later property is the most interesting because it provides a three-dimensional imaging.

It has been shown earlier [2] that a two-dimensional photonic crystal (PC) made from a non-magnetic dielectric is a LHM in the sense defined by Veselago. A numerical simulation can find the negative values of e and µ. Using these values we the Veselago lens, a unique optical device predicted by Veselago, was simulated. The interest in LHM was significantly amplified by the work of Pendry [3] who argued that the Veselago lens is a ''perfect lens'' in the sense that it gives a perfect image of the point source. This statement is based upon the observation that the evanescent waves (EW's) that usually decay in the near field region are amplified by the LHM. Pendry claimed that the amplified EW’s restore a perfect image.

It is shown in this paper that negative e and µ recently discovered in a PC are properties of propagating modes only. The EW’s rather decay than increase in the bulk of the crystal if a surface does not support surface waves. If it does, the EW’s may improve the image of the lens. The diffraction limit for the Veselago lens is presented.

[1] V. G. Veselago: Sov. Phys.-Solid State Vol. 8 (1967), p. 2854.

[2] A. L. Efros, A. L. Pokrovsky: Solid State Comm. Vol. 129 (2004), p.643.

[3] J. B. Pendry: Phys. Rev. Lett. Vol. 85 (2000), p. 39.

The audience, including graduate students, are invited to meet the speaker 15 minutes beforehand over wine and cheese in the Physics Common Room.

Further Information

Contact

Professor Oleg Sushkov