Non-regularly shaped plasmon resonant nanoparticle as localized light source for near-field microscopy.
We study numerically two-dimensional nanoparticles with a non-regular shape and demonstrate that these particles can support many more plasmon resonances than a particle with a regular shape (e.g. an ellipse). The electric field distributions associated with these different resonances are investigated in detail in the context of near-field microscopy. Depending on the particle shape, extremely strong and localized near-fields, with intensity larger than 105 that of the illumination wave, can be generated. We also discuss the spectral dependence of these near-fields and show that different spatial distributions are observed, depending which plasmon resonance is excited in the particle.
Kottmann
J P
JP
Electromagnetic Fields and Microwave Electronics Laboratory, Swiss Federal Institute of Technology, ETH-Zentrum, Gloriastrasse 35, 8092 Zurich, Switzerland.
Martin
O J
OJ
Smith
D R
DR
Schultz
S
S