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Beaming of light at broadside through a subwavelength hole: Leaky wave model and open stopband effect
Author(s) -
Jackson D. R.,
Oliner A. A.,
Zhao T.,
Williams J. T.
Publication year - 2005
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/2004rs003226
Subject(s) - stopband , broadside , leaky wave antenna , optics , surface plasmon , beam (structure) , aperture (computer memory) , plasmon , surface wave , physics , leaky mode , extraordinary optical transmission , materials science , antenna (radio) , acoustics , surface plasmon polariton , resonator , laser , microstrip antenna , telecommunications , computer science , single mode optical fiber , radiation mode
The optical transmission through a subwavelength hole in a metal film is usually very small, and the beam radiated from its exit aperture is very broad. However, the transmission may be increased by orders of magnitude, and the output beam sharply narrowed, when the tiny hole is surrounded by a properly designed periodic structure, which may take the form of an array of grooves or indentations on the metal surface. We have shown that these dramatic effects are due to the excitation of a leaky surface plasmon mode by the periodic structure on the metal film. Following this understanding, we introduce a simple but effective leaky wave antenna model, which we use to further explain and to quantify these dramatic effects. Particular attention is given to optimizing the structure to achieve maximum radiation at broadside, which offers a significant challenge in view of the open stopband in precisely the broadside direction.