Symmetry control of strong chiral light matter interactions in photonic nanocavities for efficient circularly polarised emission

Abstract: Chiral excited electronic states of molecules have an intrinsic sense of handedness, or twist, and are the active component in energy efficient display technologies and in new photosynthetic routes to produce pharmaceuticals. Creating chiral states is achieved by manipulating the twistiness of the geometric molecular structure. This is a demanding problem adding complexity due to the need to precisely control molecular geometry. Here we demonstrate a novel concept for creating chiral excited states which does not rely on molecular structure. Instead, it depends on hybridising a non chiral molecule with a chiral electromagnetic field, producing a hybrid light matter chiral polariton state. This is achieved by a symmetry controlled strong chiral-light matter interaction between an electromagnetic mode of a chiral nanocavity and an achiral molecule, a concept referred to as the electromagnetic enantiomer. This electromagnetic mechanism simplifies the creation of chiral electronic states since it is far less demanding in terms of materials design. We have illustrated the concept using an exemplar system relevant to organic optoelectronic technology, producing efficient circularly polarised emission from a non-chiral emitter molecule.