High order standing-wave plasmon resonances in silver u-shaped nanowires

Optical measurements of the transmission spectra through nanofabricated planar arrays of silver u-shaped nanowires on a silicon substrate resonating at infrared frequencies are performed. Good agreement with the numerically simulated surface plasmon standing wave resonances supported by the structures is found. Such resonances exhibit field enhancement and are able to provide magnetic and electric responses when used as the unit cell of a metamaterial. The magnetic excitation of the resonators using oblique incidence is shown to be drastically reduced by the existence of a high index substrate such as silicon. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4759444]