Aluminum based structures for manipulating short visible wavelength in-plane surface plasmon polariton propagation.

We report aluminum based structures for manipulation of surface plasmon polariton (SPP) propagation at short wavelength range. Our simulation shows that aluminum is a good metal to excite and propagate SPPs with blue light and that the SPP wavelength can be reduced from about 465 nm to about 265 nm by monitoring the thickness of a coated Si(3)N(4) layer above the aluminum film. It is also shown that the damping becomes more significant with the increase of the thickness of the Si(3)N(4) layer. We also experimentally demonstrated the SPP wavelength tuning effect for 20nm Si(3)N(4) layer covered Al, which can be explained by the variation of effective permittivity. The proposed Metal-Insulator-Air (MIA) structures with SPP wavelength tuning ability have potential applications in 2D optics.