'Chirality, Duality, Helicity - and how it’s ...'
Carsten Rockstuhl (Institute of Theoretical Solid State Physics and Institute of Nanotechnology, Karlsruhe Institute ofTechnology)
'Chirality, Duality, Helicity - and how it’s all intertwined'
Abstract: Chirality is a ubiquitous theme in science andgained particular attention in photonics. There, it is encountered in two flavors.On the one hand, objects can be chiral. It implies that the object cannot besuperimposed onto its mirror image by any rotation or translation. On the otherhand, the response from such objects is probed with light that is sometimessaid to be chiral while we actually refer to its helicity. Now, helicity is thegenerator of the duality transformation, which establishes the link between thethree terms mentioned in the title. Dual objects preserve the helicity of lightand possess the same electric and magnetic response. Therefore, it is by nosurprise that in the slipstream of research on metamaterials, dual objects andtheir applications gained attention.
This talk gives an overview on some aspects inthis research field, emphasizing the connection between the terms mentioned inthe title. It starts with chiral photonic materials and asks the question howto quantify and measure the chirality of an object (as an answer we introducethe ‘electromagnetic chirality’). It discusses maximal electromagnetic chiralobjects (that necessarily have to be dual) and formulate requirements an objecthas to met to improve our ability to sense chiral molecules in its entiresurrounding (the object should actually not be chiral but dual).