Near field enhancements in Ag Au nanosphere heterodimers

EZEQUIEL R. ENCINA; EDUARDO A. CORONADO

AMER CHEMICAL SOC

Año: 2011 vol. 115 p. 15908 - 15908

he near field enhancement in Ag Au nanospheres heterodimers excited at theirrespective resonance wavelengths is studied in detail using rigorous electrodynamicscalculations based on the Generalized Multiparticle Mie theory. The effect of incidentpolarization, nanosphere radius and interparticle separation on the distribution patternand magnitude of the near field enhancement is analyzed. As in the homodimer case, thehighest enhancement values are found for incident polarization parallel to the dimeraxis. However, there are significant different enhancement patterns around the dimeraccording to the excitation wavelength. Analyzing the vector field plot of theenhancement, and comparing it with those corresponding to Ag and Au nanosphereshomodimers, the differences observed are rationalized in terms of multipole excitationsto explain the effect of breaking the symmetry of the plasmonic heterodimer. The resultspresented cou