Negative Refraction in Natural Materials

Negative refraction occurs at interfaces as a natural consequence of the negative group velocity of waves in one of the interfacing media. The historical origin of this understanding of the phenomenon is briefly discussed. We consider several physical systems that may exhibit normal electromagnetic waves (polaritons) with negative group velocity at optical frequencies. These systems are analyzed in a unified way provided by the spatial dispersion framework. The framework utilizes the notion of the generalized dielectric tensor e _{i j} (omega;k) representing the electromagnetic response of the medium to perturbations of frequency omega and wave vector k. Polaritons with negative group velocity can exist in media (whether in natural or in artificial meta-materials) with a sufficiently strong spatial dispersion. Our examples include both gyrotropic and nongyrotropic systems, and bulk and surface polariton waves. We also discuss the relation between the spatial dispersion approach and the more familiar, but more restricted, description involving the dielectric permittivity eps(omega) and the magnetic permeability mu(omega).
Vladimir Agranovich graduated from the Physics Department of Kiev State University in 1951. In 1955, he received his PhD in Kiev, Doctor of Science degree in 1961 from Institute of Chemical Physics (Moscow) and the Professor Diploma from the Commission of Government in 1963. Between 1956 and 1969 he was Head of Theoretical Laboratory of Physical-Energetical Institute in Obninsk, and in 1969 he joined the newly founded Institute of Spectroscopy of the Russian Academy of Science as Head of the Theoretical Department. He has published approximately 400 papers, three books and many invited chapters in contributed volumes.

In 1992, Professor Agranovich received the Humboldt Research Award from Alexander forn Humboldt-Foundation in Germany, the Kapiza Award in the UK in 1993, and the Mandelstam Award from the Russian Academy of Science. He is a Fellow of Institute of Physics of the UK and holds the title Doctor Honoris Causa from Blaise Pascal University in Clermont-Ferrand, France. In 2002, Professor Agranovich was appointed “Pioneer of Nano-Science” at the University of Texas, Dallas. Professor Agranovich in 1965 together with the 2003 Nobel Laureate V.L. Ginzburg published the monograph “Crystal Optics with Spatial Dispersion, and Excitons” (the third edition of this book is in preparation).

In 1968, he published the monograph “Theory of Excitons” (the book is currently being updated and translated to English) and in 1982 with M.D. Galanin he published the monograph “Electronic Excitation Energy Transfer in Condensed Matter”. Together with A.A. Maradudin (Irvine), V.M. Agranovich created a well-known series ”Modern Problems in Condensed Matter Science” which now comprises 35 volumes. He is also a co-editor of the series “Thin films and nanostructures” and editor of journal “Physics Letters A”.

For about 20 years he was the regional Editor of Solid State Communications and before Perestroika he was the main organizer of bilateral workshops and conferences USSR-USA, USSR- Germany, USSR-Italy, USSR- Japan and others. Professor Agranovich advised many students who are now well-known scientists distributed over research institutions in many countries.