Strong influence of hole shape on extraordinary transmission through periodic arrays sub-wavelength holes
Résumé
We show that extraordinary light transmission of periodic subwavelength hole arrays, generally attributed to surface-plasmon resonances, is strongly influenced by the hole shape. Both experiments and calculations, based on a Fourier modal method, demonstrate that a shape change from circular to
rectangular increases the normalized transmission by an order of magnitude while the hole area decreases. Moreover, the spectra exhibit large redshifts (2500 cm1). A comparison with the transmission of isolated holes shows that shape resonances of the rectangular holes play a dominant role.
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