The influence of hole shape on enhancing transmission through subwavelength hole arrays

The extraordinary light transmission through a 200-nm thick goldfilm when passing through different subwavelength hole arrays isobserved experimentally. The sample is fabricated by electron beamlithography and reactive ion etching system. A comparison betweenlight transmissions shows that the hole shape changing fromrectangular to diamond strongly affects the transmission intensityalthough both structures possess the same lattice constant of600,nm. Moreover, the position of the transmission maximumundergoes a spectral red-shift of about 63,nm. Numericalsimulations by using a transfer matrix method reproduce the observedtransmission spectrum quite well.