Supplement to:
Finite element simulation of a perturbed axial-symmetric whispering-gallery mode and its use for intensity enhancement with a nanoparticle coupled to a microtoroid

Alex Kaplan,1,2 Matthew Tomes,1 Tal Carmon,1* Maxim Kozlov,2 Oren Cohen,2 Guy Bartal,3 and Harald G. L. Schwefel4,5

1Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109, USA
2Department of Physics and Solid State Institute, Technion, Haifa 32000, Israel
3Department of Electrical Engineering, Technion, Haifa 32000, Israel
4Max Planck Institute for the Science of Light, 91058 Erlangen, Germany
5Institute for Optics, Information and Photonics, University of Erlangen–Nuremberg, 91058 Erlangen, Germany 


Abstract: We present an optical mode solver for a whispering gallery resonator coupled to an adjacent arbitrary shaped nano-particle that breaks the axial symmetry of the resonator. Such a hybrid resonator-nanoparticle is similar to what was recently used for bio-detection and for field enhancement. We demonstrate our solver by parametrically studying a toroid-nanoplasmonic device and get the optimal nano-plasmonic size for maximal enhancement. We investigate cases near a plasmonic resonance as well as far from a plasmonic resonance. Unlike common plasmons that typically benefit from working near their resonance, here working far from plasmonic resonance provides comparable performance. This is because the plasmonic resonance enhancement is accompanied by cavity quality degradation through plasmonic absorption.

Code to generate the Figure 4 of our publication Optics Express, Vol. 21, Issue 12, pp. 14169-14180 (2013)
or for Figure 3 of arXiv:1305.0555 . Please feel free to use it, but please cite us properly. The file using comsol version 4.3a can be found here: download file


Fig. 3: Solution for a non-symmetrical nanoparticle configuration. A gold ellipsoid with semiaxis lengths of 10, 20 and 200 nm was located 24 nm away from a silica toroid that is resonating at 1.55 µm vacuum wavelength. The ellipsoid is rotated at an arbitrary angle along an arbitrary direction vector. All other parameters are as in (Figs. 1,3,5). Colors describe the electric field normal. A detailed description of how to generate this figure, including a sample file, is added in the Supplement.

© 2013 by Harald G. L. Schwefel