Tailorable chiral optical response through coupling among plasmonic meta-atoms with distinct shapes

Chiral plasmonic nanostructures with giant and tunable chiral optical responses hold great potential in chiral sensing applications for chemistry, biology, and pharmacy, etc. For the origin of the chiral optical response of artificial plasmonic chiral assemblies, resonant and off-resonant coupling mechanisms have been figured out. However, most existing chiral plasmonic assemblies are based on only one mechanism, where strong optical chirality always compromises with spectral tunability. To release the trade-off between the strength and spectral tunability, we employ a combination of resonant and off-resonant coupling mechanisms and demonstrate a pronounced and tailorable chiral optical response based on plasmonic meta-atoms with distinct shapes. We anticipate that our strategy provides more flexibility in designing chiral plamsonic nanostructures and promotes the field further towards customized chiral plasmonic platforms. (C) 2018 Optical Society of America