Hexagonal arrays of gold triangles as plasmonic tweezers

We present theoretical and experimental studies of the plasmonic properties of hexagonal arrays of gold triangles, fabricated by angle-resolved nanosphere lithography method. Our numerical and experimental results both show that a change in the angle of gold deposition affects the size and the distance between the triangles, leading to a controlled shift in their absorption and scattering spectra. We calculate the force exerted on the polystyrene particles of 650 nm radii numerically while passing above the hexagonal arrays. Simulation results show that the presented hexagonal arrays of gold triangles can operate as efficient plasmonic tweezers with a controllable operating wavelength and high trap strength, owing to the additive interaction of the neighboring triangles. Moreover, we apply the realized plasmonic nanostructures in a conventional optical tweezers configuration and show that the optical tweezers stiffness can be effectively modulated by the plasmonic forces, at the IR wavelength of 1064 nm.