Publication Type
Journal
Journal Name
Optics Letters
Publication Date
Page Numbers
2124 to 2126
Volume
35
Issue
13
Abstract
We measure the transmission of infra-red radiation through double-layer metal ¯lms with periodic arrays
of subwavelength holes. When the two metal ¯lms are placed in su±ciently close proximity, two types of
transmission resonances emerge. For the surface plasmon mode, the electromagnetic ¯eld is concentrated on
the outer surface of the entire metallic layer stack. In contrast, for the guided mode the ¯eld is con¯ned to
the gap between the two metal layers. Our measurements indicate that as the two layers are laterally shifted
from perfect alignment, the peak transmission frequency of the guided mode decreases signi¯cantly, while that
of the surface plasmon mode remains largely unchanged, in agreement with numerical calculations.
