Plasmonic and Photonic Enhancement of Chiral Near‐Fields

A chiral near‐field with a highly contorted electromagnetic field builds a bridge to match chiral molecules and light wavelengths with large size differences. It significantly enhances the circular dichroism of chiral molecules and has great prospects in chirality sensing, detection, trapping, and other chirality‐related applications. Surface plasmons feature outstanding light‐trapping and electromagnetic‐field‐concentrating abilities. Plasmonic chiral nanostructures facilitate light manipulation to generate superchiral near‐fields. Meanwhile, the nanophotonic structures have attracted significant interest to obtain strong chiral near‐fields due to their unique electromagnetic resonant properties. During the interaction of light and chiral materials, the chiral near‐field not only bridges the light and chiral molecules but is also responsible for the optical activities. This paper reviews state‐of‐the‐art studies on generating or enhancing chiral near‐fields using plasmonic and photonic nanostructures. The principle of chiral near‐fields and the development of chiral near‐fields with plasmonic and photonic nanostructures are reviewed. The properties and applications of enhanced chiral near‐fields for chiral molecule detection, spin‐orbit angular interaction, and the generation of the chiral optical force are examined. Finally, current challenges are discussed and a brief outlook of this field is provided.