Abstract
We present a simple masked thermal evaporation technique to fabricate arrays of wirelike
Ag
microstructures of width
8
μ
m
with an extremely high aspect ratio on either silicon or glass substrates. In accordance with the theory of periodic arrays of thin wires, the electromagnetic response of
Ag
microstructures has shown a characteristic low-frequency plasmonic behavior with a transparent visible region. Plasmon absorption is observed to be splitted largely into transverse and predominating longitudinal bands at near-ultraviolet
(
415
nm
)
and midinfrared wavelengths
(
2867
nm
)
, corresponding to the oscillation of the free electrons perpendicular to and along the long axis of the wires.