  Selective configuration control of plasmonic nanostructures using either
top-down or bottom-up approaches has remained challenging in the field of
active plasmonics. We demonstrate the realization of DNA-assembled
reconfigurable plasmonic metamolecules, which can respond to a wide range of pH
changes in a programmable manner. This programmability allows for selective
reconfiguration of different plasmonic metamolecule species coexisting in
solution through simple pH tuning. This approach enables discrimination of
chiral plasmonic quasi-enantiomers and arbitrary tuning of chiroptical effects
with unprecedented degrees of freedom. Our work outlines a new blueprint for
implementation of advanced active plasmonic systems, in which individual
structural species can be programmed to perform multiple tasks and functions in
response to independent external stimuli.
