Formation of enhanced opposite one-handed chiral fields in heterodimer-film nanostructures
Plasmonic chirality has attracted a lot of interests because it could result in dramatically increased chiroptical interactions and offer many potential applications in chiral molecules analysis, catalysis, and other nanotechnology. In particular, one-handed chiral field is required in many applications for the reason that molecules are generally distributed randomly in some region of structures. In this work, benefiting from the coupling effect and energy focusing effect, we propose a heterodimer-film nanostructure to achieve one-handed chiral fields under linearly polarized light illumination. The results indicate that there are just opposite one-handed chiral fields in different gaps of the heterodimer-film nanostructure. The volume averaged optical chirality in the gaps can reach 102 and the optical chirality of hot spots can reach 103, which has potential applications in chiral sensing and Raman optical activity.