MechanotunableSurface Lattice Resonances in the VisibleOptical Range by Soft Lithography Templates and Directed Self-Assembly

We demonstrate a novel colloidal self-assembly approach toward obtaining mechanically tunable, cost-efficient and low-loss plasmonic nanostructures that show pronounced optical anisotropy upon mechanical deformation. Soft lithography and template-assisted colloidal self-assembly are used to fabricate a stretchable periodic square lattice of gold nanoparticles on macroscopic areas. We stress the impact of particle size distribution on the resulting optical properties. To this end, lattices of narrowly distributed particles (~2% standard deviation in diameter) are compared with those composed of polydisperse ones (~14% standard deviation). The enhanced particle quality sharpens the collective surface lattice resonances by 40% to achieve a full width at half maximum as low as 16 nm. This high optical quality approaches the theoretical limit for this system, as revealed by electromagnetic simulations. 100 stretching cycles demonstrate a reversible transformation from square to rectangular lattice, accompanied...