Abstract
Propagation of electromagnetic waves - including microwaves, terrahertz waves and light - is inherently bi-directional in ‘normal’ material systems, a natural consequence of so-called ‘time-reversal symmetry’ deriving from the laws of elecgtromagnetism. Fortunately, in practice, there are several known techniques to circumvent this constraint to achieve “electromagnetic isolation” in engineered systems - critically important for such applications as mobile radio, radar, optical fibre communication networks.
Traditional solutions, though, are generally bulky, presenting difficulties for achieving the desired compact, modern, highly-integrated systems. This is particularly problematic at elevated frequencies, such as with terahertz and light-wave systems, which, owing to the short wavelengths involved, would otherwise allow the development of compact systems with very small dimensions.
However, in recent years, accompanied by the development of meta-material systems to allow practical realisation, there have been new developments in elecromagnetic theory - freed from the constraints of ‘normal, found in nature, materials properties’ - that offer the prospect of new approaches.
In his talk, Professor Silveirinha will present his vision of how the time-reversal symmetry can be broken with “mechanical motion”, such as by injecting a drift electric current into material. This provides the basis for further research his group will undertake supported by the IET A F Harvey prize funds. He will show how such solutions may enable the one-way propagation of terahertz waves totally immune to the undesired effects of back-scattering by obstacles, imperfections, and other deformations of the propagation path.
