Strong influence of hole shape on extraordinary transmission through periodic arrays of subwavelength holes.
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 (approximately 2500 cm(-1)). A comparison with the transmission of isolated holes shows that shape resonances of the rectangular holes play a dominant role.
Koerkamp
K J Klein
KJ
Applied Optics Group, MESA+ Institute for Nanotechnology and Department of Science & Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Enoch
S
S
Segerink
F B
FB
van Hulst
N F
NF
Kuipers
L
L