The explosive growth in the development of plasmonic devices for sensors, switches, catalysis 

and optical data links is driving the evolution of increasingly sophisticated nanostructures for 

these applications. Arrays of ultrathin Archimedean nanospirals exhibit linear and nonlinear 

optical properties associated with near-field plasmon resonances within the nanostructures. The 

enhanced electric fields at these resonances enable efficient second-harmonic generation (SHG)

because individual nanospirals have no symmetry axis. We observe efficient SHG from arrays 

of lithographically fabricated, sub-wavelength-dimension nanospirals, initiated by transform-

limited 15 fs pulses at a wavelength of 800 nm. The nanospiral arrays respond selectively to 

incident linear and circular polarization states and exhibit conversion among polarization states. 

I will conclude by suggesting some ways in which the asymmetry and two-dimensional chirality 

of the nanospirals may lead to interesting applications in metamaterial devices.