Chiro-Optical Structures with Magnetizable Plasmonic Elements for Modulating the Chiral Transmission of Light

Abstract: Manipulating external stimuli is crucial for enhancing and controlling the optical response in chiral structures. This study introduces chiral structures composed of single, dimer, or trimer arrays of plasmonic and magneto-plasmonic trapezoidal and triangular nanoantennas. Through modeling, we demonstrate how these systems can (i) function as chiral metasurfaces, (ii) modulate chiral light absorption via an external magnetic field, (iii) magnetically enhance the chiro-optical response, and (iv) improve the chiro-optical and magneto-chiral response through structural engineering. By optimizing the nanoantenna geometry, we achieve enhancements larger than 100 in the chiro-optical signal of a magnetized Ni monomer compared to a non-magnetized system. Additionally, we model bimetallic systems, showing a ~2-fold increase in chiro-optical response for hybrid Au and Ni magneto-plasmonic systems compared to purely plasmonic Au systems, while simultaneously enabling magnetic tuning of the optical response. Our results highlight the potential of structurally engineered magneto-plasmonic nanoantennas for advanced applications in chiro-optical sensing and tunable photonic devices.