Detection limit of plasmonic antennas
© 2014 EPFL
We use numerical simulations based on the surface integral technique to study the detection limit of plasmonic trapping with realistic dipole antennas. The induced plasmon resonance shift due to the coupling between an antenna and a nanoparticle is studied for different antennas geometries, different positions, sizes, and materials for the trapped nanoparticle. The shift of the antenna resonance is found to be linear with the near-field intensity enhancement caused by the antenna and further dependents on the volume and refractive index of the trapped nanoparticle. Detection limit of 5 nm for plasmonic particles and 6.5 nm for high index dielectrics is reported.
Having previously demonstrated that plasmonic antennas can be used for trapping at the nanoscale, we have now investigated the detection limit of such an antenna. The induced plasmon resonance shift due to the coupling between the antenna and a nanoparticle trapped near the antenna is studied for different antennas geometries, different positions, sizes, and materials for the trapped nanoparticle. The shift of the antenna resonance is found to be linear with the near-field intensity enhancement caused by the antenna and further dependents on the volume and refractive index of the trapped nanoparticle. Detection limit of 5 nm for plasmonic particles and 6.5 nm for high index dielectrics is reported.
Calculations of the response of a realistic plasmonic antenna when a metal nanoparticle is trapped within its gap. The corresponding detuning of the antenna as a function of the metal nanoparticle is shown on the right panel. This detuning determines the detection limit.
Check the corresponding publication: PDF External link: doi: 10.1063/1.3650267