Single-Handedness Chiral Optical Cavities

Geometrical chirality is a universal phenomenon that is encountered on many different length scales ranging from geometrical shapes of various living organisms to protein and DNA molecules. Interaction of chiral matter with chiral light - that is, electromagnetic field possessing a certain handedness - underlies our ability to discriminate enantiomers of chiral molecules. In this context, it is often desired to have an optical cavity that would efficiently couple to only a specific (right or left) molecular enantiomer, and not couple to the opposite one. Here, we demonstrate a single-handedness chiral optical cavity supporting only an eigenmode of a given handedness without the presence of modes of other helicity. Resonant excitation of the cavity with light of appropriate handedness enables formation of a helical standing wave with a uniform chirality density, while the opposite handedness does not cause any resonant effects. Furthermore, only chiral emitters of the matching handedness efficiently interact with such a chiral eigenmode, enabling the handedness-selective coupling light-matter strength. The proposed system expands the set of tools available for investigations of chiral matter and opens the door to studies of chiral electromagnetic vacuum.