A new twist in the properties of light

Light has some well-established dynamical properties that have defined our understanding of electromagnetic radiation for over a century. Two of the most fundamental of these properties are that photons of light carry momentum in the direction of propagation, and a 'spin' about the propagation axis defined by the electromagnetic wave's circular polarization. These properties play critical roles in a range of everyday phenomena and experimental interactions between light and matter.

Konstantin Bliokh from the RIKEN Interdisciplinary Theoretical Science Research Group (iTHES) and Aleksandr Bekshaev and Franco Nori from the RIKEN Center for Emergent Matter Science have now made the remarkable discovery that a particular type of light known as evanescent waves possesses unexpected dynamical properties that are in sharp contrast with previous knowledge about light and photons.