Dresden 2011 – scientific programme

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O: Fachverband Oberflächenphysik

O 18: Plasmonics and Nanooptics II

O 18.5: Talk

Monday, March 14, 2011, 18:15–18:30, PHY C213

Parallel nanostructuring of fused silica exploiting local near fields — •Sören Maag, Rodica Morarescu, Frank Träger, and Frank Hubenthal — Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany

In modern nanotechnology, there is an ongoing interest to decrease the dimensions of surface structures below the diffraction limit. Furthermore, parallel structuring of surfaces with light induced processes is of particular interest. Along these lines we are using nanosphere lithography to create highly ordered triangular gold nanoparticle arrays and exploit their localized optical near field to overcome locally the ablation threshold of fused silicia. Therefore, the nanoparticle arrays were irradiated with a single ultrashort laser pulse (35 fs), at a central wavelength of 790 nm. Depending on the polarization and the fluence of the laser light holes, grooves, or channels, with dimensions well below the diffraction limit have been created. For example, for a polarization along the bisector of the triangular nanoparticles, nanogrooves with a depth of 14 nm, a width at its waist of 45 nm, and a length of 290 nm have been generated, if fluences near the ablation threshold were applied. In contrast, tiny spherical nanoholes with diameters of only 23 nm can be achieved, for fluences significantly below the ablation threshold. The obtained structures can be explained by the enhanced electromagnetic near fields, which overcome locally the ablation threshold of fused silica in the vicinity of the irradiated nanoparticles.