Assessing the plasmonics of gold nano-triangles with higher order laser modes

• Laura E. Hennemann,
• Andreas Kolloch,
• Andreas Kern,
• Josip Mihaljevic,
• Johannes Boneberg,
• Paul Leiderer,
• Alfred J. Meixner and
• Dai Zhang

Beilstein J. Nanotechnol. 2012, 3, 674–683, doi:10.3762/bjnano.3.77

• with a parabolic mirror based confocal microscope where the sample is scanned through the laser focus. By employing higher order laser modes (azimuthally and radially polarised laser beams), we can excite the Fischer patterns using either a pure in-plane (x,y) electric field or a strongly z-directional

• order laser modes have been reported so far. Here we present the investigation of gold nano-triangle Fischer patterns with a custom built confocal microscope. The use of higher order laser modes allows for the tuning of the polarisation in the laser focus so that it can be either perpendicular to the

• described previously [21][22]. The Gaussian beam of a helium-neon laser (λ = 632.8 nm) is transformed by a mode converter to generate higher order laser modes: either a radially or an azimuthally polarised donut mode [23][24]. This mode is then focused onto the sample surface by a parabolic mirror of high