TY - JOUR T1 - Extinction vs Absorption: Which Is the Indicator of Plasmonic Field Strength for Silver Nanocubes? JF - Journal of Physical Chemistry C Y1 - 2012 A1 - Near, R. A1 - Hayden, S. A1 - El-Sayed, M. AB - This investigation demonstrates the contributions of absorption and scattering to the extinction spectrum of silver nanocubes with multipole resonances and the complexity of the resulting plasmon field strengths for these varying modes. The three-dimensional plasmonic field distribution and orientation around a silver nanosphere (AgNS; 40 nm) and a silver nanocube (AgNC; 40, 60, 86 nm) were calculated in the visible via the discrete dipole approximation. The three-dimensional nature of these particles allows for significant contribution from the quadrupole mode in some cases. The AgNS displays one plasmon band, its dipole mode, and has little contribution from scattering. The maximum plasmon field occurs at the extinction maximum, as expected. The 40 nm AgNC exhibits multiple plasmon bands, and the highest maximum field strength is attained from excitation of the quadrupole mode, not the dipole mode. As the size of the AgNC increases, the contribution from scattering increases. When the contribution from scattering is greater than the contribution from absorption in a AgNC, the field strength within a plasmon mode trends with the absorption and not with the extinction or cattering. This should be considered in applications of AgNCs, as excitation of the largest peak in the experimental extinction spectrum will not always result in the strongest plasmon field strength. VL - 116 SN - 1932-7447 N1 - Times Cited: 0Near, Rachel Hayden, Steven El-Sayed, Mostafa M3 - 10.1021/jp309272b ER - TY - JOUR T1 - Pronounced Effects of Anisotropy on Plasmonic Properties of Nanorings Fabricated by Electron Beam Lithography JF - Nano Letters Y1 - 2012 A1 - Near, R. A1 - Tabor, C. A1 - Duan, J. S. A1 - Pachter, R. A1 - El-Sayed, M. AB - Gold nanoring dimers were fabricated via EBL with dimensions of 127.6 +/- 2.5 and 57.8 +/- 2.3 nm for the outer and inner diameters, respectively, with interparticle separations ranging from 17.8 +/- 3.4 to 239.2 +/- 3.7 nm. The coupling between the inner and outer surfaces of a single nanoring renders it very sensitive to any anisotropy. We found that anisotropy in the particle geometry and anisotropy introduced by the substrate combine to create very unique spectral features in this system. VL - 12 SN - 1530-6984 N1 - Times Cited: 3Near, Rachel Tabor, Christopher Duan, Jinsong Pachter, Ruth El-Sayed, Mostafa M3 - 10.1021/nl300622p ER -