Regensburg 2010 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 10: Plasmonics and Nanophotonics I (Joint Session DS/O/HL)
DS 10.4: Vortrag
Dienstag, 23. März 2010, 11:15–11:30, H2
Suppressed transmission through ultrathin metal films by subwavelength hole arrays — •Julia Braun1, Bruno Gompf1, Uwe Huebner2, and Martin Dressel1 — 11. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart — 2IPHT Jena, Albert-Einstein-Straße 9, 07745 Jena
If an opaque metal film is periodically perforated by tiny subwavelength holes, extraordinary high transmission is observed [1]. We investigate the transmission through subwavelength hole arrays (SWHA) in ultrathin semitransparent Au films with various periodicities and hole diameters and observe the opposite behavior: less light is transmitted through the pierced metal compared to the closed film. The samples were fabricated by optical interference and electron beam lithography in 12 nm and 20 nm thick Au films with periodicities between 250 nm and 400 nm, and than characterized in the frequency range 4400 cm−1 to 37000 cm−1 (0.6 eV to 4.6 eV). The optical properties of SWHA cannot be explained by a pure dielectric function, but show a strong k→-dependent behavior. In ultrathin Au films it is marked by the excitation of strongly damped antisymmetric short range surface plasmons. The obtained dispersion curves perfectly agree with this explanation when the altered dielectric function of the ultrathin Au films is taken into account [2].
[1] T.W. Ebessen, H.J. Lezec, H.F. Ghaemi, T. Thio, and P.A. Wolff, Nature 391, 667 (1998).
[2] J. Braun, B. Gompf, G. Kobiela, M. Dressel, Physical Review Letters 103, 203901 (2009)