Katherine Parrish will defend her doctoral dissertation “Investigating Chiral Light-Matter Interactions in Photonic Materials.”
A phenomenon observed in some oriented materials is apparent circular dichroism (ACD), a differential absorption of left and right circularly polarized light that is opposite for counterpropagating light. In contrast to conventional circular dichroism, which originates from a sample’s 3D chirality and is independent of the direction of light propagation, ACD is the result of an interference between linear birefringence (LB) and linear dichroism (LD) in a material exhibiting 2D chirality. In this dissertation, I discuss the realization of a 2D chiral microcavity: by embedding ACD-active organic thin films in planar Fabry-Pérot microcavities, we demonstrated enhanced chiroptical signals over an order of magnitude greater than those exhibited by the isolated thin films. We also characterized the spatial, spectral, and angular chiroptical responses of this 2D chiral microcavity. Engineering such strong asymmetric transmission in microcavities could enable a variety of chiral light-matter phenomena with applications in quantum informatics and chiral lasing. I also discuss the first experimental demonstration of ACD by a centrosymmetric inorganic material, Li2Co3(SeO3)4, which has potential for use in similar applications.