At large number of colors, Nc quarks in baryons are in a mean field of definite space and flavor symmetry. We write down the general Lorentz and flavor structure of the mean field, and derive the Dirac equation for quarks in that field. The resulting baryon resonances exhibit an hierarchy of scales: The crude mass is O(Nc), the intrinsic quark excitations are O(1), and each intrinsic quark stat...

Biosensing Based on Localized Surface Plasmon Resonance of Gold Nanostructures Fabricated by a Novel Nanosphere Lithography Technique

Unlike silver and gold, aluminum has material properties that enable strong plasmon resonances spanning much of the visible region of the spectrum and into the ultraviolet. This extended response, combined with its natural abundance, low cost, and amenability to manufacturing processes, makes aluminum a highly promising material for commercial applications. Fabricating Al-based nanostructures w...

Surface plasmon resonance (SPR) sensing is an optical technique that allows real time detection of small changes in the physical properties, in particular in the refractive index, of a dielectric medium near a metal film surface. One way to increase the SPR signal shift is then to incorporate a substance possessing a strong dispersive refractive index in the range of the plasmon resonance band....

Coupling between tunable broadband modes of an array of plasmonic metamolecules and a vibrational mode of carbonyl bond of poly(methyl methacrylate) is shown experimentally to produce a Fano resonance, which can be tuned in situ by varying the polarization of incident light. The interaction between the plasmon modes and the molecular resonance is investigated using both rigorous electromagnetic...

The effect of nanoscale surface roughness on the gap plasmon resonance of gold nanoparticles on thermally evaporated gold films is investigated experimentally and numerically. Single-particle scattering spectra obtained from 80 nm diameter gold particles on a gold film show significant particle-to-particle variation of the peak scattering wavelength of ±28 nm. The experimental results are compa...

We report abnormally large positive and negative lateral optical beam shifts at a metal–air interface when the surface plasmon resonance of the metal is excited. The optimal thickness for minimal resonant reflection is identified as the critical thickness above which a negative beam displacement is observed. Experimental results show good agreement with theoretical predictions and the large obs...

Metal nanostructures show great applications in chemical sensing, biomedical detection, optical-thermal therapy, and optical communications because of their electromagnetic field enhancement properties at the visible and the near-field infrared wavelengths. Such strong optical field enhancement induced by the localized surface plasmon resonance is dependent on the configurations and the sizes o...

We demonstrate a three dimensional nanoparticle trapping approach aided by the surface plasmon resonance of metallic nanostructures. The localized surface plasmon resonance effect provides strong electromagnetic field enhancement, which enables confinement of nanoparticles in the three-dimensional space. Numerical simulations indicate that the plasmonic structure provides approximately two orde...