Disposable Plasmonics: Rapid and Inexpensive Large Area Patterning of Plasmonic Structures with CO2 Laser Annealing.

We present a method of direct patterning of plasmonic nanofeatures on glass that is fast, scalable, tunable, and accessible to a wide range of users-a unique combination in the context of current nanofabrication options for plasmonic devices. These benefits are made possible by the localized heating and subsequent annealing of thin metal films using infrared light from a commercial CO2 laser system. This approach results in patterning times of 30 mm(2)/min with an average cost of $0.10/mm(2). Colloidal Au nanoparticles with diameters between 15 and 40 nm can be formed on glass surfaces with x-y patterning resolutions of ∼180 µm. While the higher resolution provided by lithography is essential in many applications, in cases where the spatial patterning resolution threshold is lower, commercial CO2 laser processing can be 30-fold faster and 400-fold less expensive.

Magnetic metamaterials in the blue range using aluminum nanostructures.

We report an experimental and theoretical study of the optical properties of two-dimensional arrays of aluminum nanoparticle in-tandem pairs. Plasmon resonances and effective optical constants of these structures are investigated, and strong magnetic response as well as negative permeability is observed down to 400 nm wavelength. Theoretical calculations based on the finite-difference time-domain method are performed for various particle dimensions and lattice parameters, and are found to be in good agreement with the experimental findings. The results show that metamaterials operating across the whole visible wavelength range are feasible.

Plasmon-enhanced sub-wavelength laser ablation: plasmonic nanojets.

In response to the incident light's electric field, the electron density oscillates in the plasmonic hotspots producing an electric current. Associated Ohmic losses raise the temperature of the material within the plasmonic hotspot above the melting point. A nanojet and nanosphere ejection can then be observed precisely from the plasmonic hotspots.

Plasmons reveal the direction of magnetization in nickel nanostructures.

We have applied the surface-sensitive nonlinear optical technique of magnetization-induced second harmonic generation (MSHG) to plasmonic, magnetic nanostructures made of Ni. We show that surface plasmon contributions to the MSHG signal can reveal the direction of the magnetization. Both the plasmonic and the magnetic nonlinear optical responses can be tuned; our results indicate novel ways to combine nanophotonics, nanoelectronics, and nanomagnetics and suggest the possibility for large magneto-chiral effects in metamaterials.