Chiral Light by Symmetric Optical Nanoantennas - SPP7 Abstract Submission Form

Addis Mekonnen Adamu Applied Physics, Chalmers University of Technology, Goteborg, Sweden Tavakol Pakizeh Faculty of Electrical Engineering, K. N. Toosi University of Technology, Tehran, Iran Irina Zubritskaya Applied Physics, Chalmers University of Technology, Goteborg, Sweden Gustav Edman Jönsson Applied Physics, Chalmers University of Technology, Goteborg, Sweden Alexandre Dmitriev Applied Physics, Chalmers University of Technology, Goteborg, Sweden

Chirality is at the origin of life and is ubiquitous in nature. An object is deemed chiral if it is non-superimposable with its own mirror image, which is then relates to a particular way a circularly polarized light interacts with such object – known as circular dichroism (CD), the differential absorption of left- and right-circularly polarized light. The conventional understanding of chiroptical effects in biology, chemistry and physics, results from an internal chiral structure or, in a special two-dimensional case, the extrinsic symmetry breaking under asymmetric illumination. Here we show that CD is possible with simple symmetric optical nanoantennas at symmetric illumination, that is – at normal incidence of light. We demonstrate that the phase lag between two electromagnetic dipole-like modes, in principle, suffice to produce far-field chiroptical response in achiral structure. This has been exemplified both is experimentally and theoretically with the all-visible spectrum archetypical optical nanoantennas – symmetric nanoellipses and nanodimers, forming large-scale metasurfaces. The simplicity and generality of this finding reveal a whole new significance of the electromagnetic design and complex media engineering at a nanoscale with potential far-reaching implications for optics in biology, chemistry and materials science.

addis@chalmers.se