Fano Resonances in Individual Coherent Plasmonic Nanocavities

Abstract

We observe the appearance of Fano resonances in the optical response of plasmonic nanocavities due to the coherent coupling between their superradiant and subradiant plasmon modes. Two reduced-symmetry nanostructures probed via confocal spectroscopy, a dolmen-style slab arrangement and a ring/disk dimer, clearly exhibit the strong polarization and geometry dependence expected for this behavior at the individual nanostructure level, confirmed by full-field electrodynamic analysis of each structure. In each case, multiple Fano resonances occur as structure size is increased.

Boosting Fano resonances in single layered concentric core–shell particles

“…One should note, however, that the FR is not efficiently excited for very small r c values. In this case, electromagnetic coupling is too weak compared to absorption losses and the resonance vanishes, i.e., the value of b increases, in analogy to the behaviour reported for dolmen plasmonic structures 55,56 .…”

Theoretical Criteria for Scattering Dark States in Nanostructured Particles

“…1 Subwavelength structures on resonance can have scattering cross sections much larger than their geometrical sizes, 2,3 and the presence of multiple resonances leads to even more possibilities through mode hybridization 4 and interference effects. [5][6][7][8][9] A particularly interesting phenomenon is the suppressed scattering in nanostructures with multiple plasmonic resonances, [10][11][12][13][14][15][16][17][18][19][20][21][22][23] plasmonic and excitonic resonances, [24][25][26][27][28][29][30] or dielectric resonances, 31,32 referred to collectively as a "scattering dark state." A wealth of models has been employed to describe this suppressed scattering, ranging from perturbative models, 12 generalization of the Fano formula, [13][14][15] and electrostatic approximation, 22,23 to coupled-mechanical-oscillator models.…”

Engineering plasmonic nanorod arrays for colon cancer marker detection

“…Recently, we have witnessed considerable efforts for the development of plasmonics and photonics-based nanosensors for biochemical and genetic analysis, especially for screening and rapid detection of cancer markers (Anker et al 2008;Cao et al 2013;Chao and Guo 2003;de la Rica and Stevens 2012;Fan et al 2010;Hao et al 2008;Luk'yanchuk et al 2010;Miroshnichenko et al 2010;Peng et al 2013;Rodriguez-Lorenzo et al 2012;Truong et al 2011;Verellen et al 2009;Wen et al 2013;Xu et al 2011;Zhang et al 2013). These systems provide a range of benefits such as shorter analysis time, lower consumption of sample, chemical reagent and energy, lower cost, and portability.…”