Learn More
The response of gold nanoparticle dimers is studied theoretically near and beyond the limit where the particles are touching. As the particles approach each other, a dominant dipole feature is observed that is pushed into the infrared due to interparticle coupling and that is associated with a large pileup of induced charge in the interparticle gap. The(More)
The semiconductor CdS is generally found in the wurtzite structure. Prior experimental and theoretical results confirm that the semiconductor CdS nanoparticles maintain a wurtzite structure for diameters greater than 6 nm. There is disagreement in the literature for sizes smaller than 6 nm. We use the density-functional theory FIREBALL code and perform(More)
The optical response of ring-shaped gold nanoparticles prepared by colloidal lithography is investigated. Compared to solid gold particles of similar size, nanorings exhibit a redshifted localized surface plasmon that can be tuned over an extended wavelength range by varying the ratio of the ring thickness to its radius. The measured wavelength variation is(More)
We study the light scattering and surface plasmon resonances of Au nanorods that are commonly used as optical nanoantennas in analogy to dipole radio antennas for chemical and biodetection field-enhanced spectroscopies and scanned-probe microscopies. With the use of the boundary element method, we calculate the nanorod near-field and far-field response to(More)
The increased resolution attained by structured illumination is based on the degree to which high spatial frequencies can be down converted into the passband of the imaging system. To effectively do this, a high contrast high-frequency illumination pattern is required. We show how the use of high numerical aperture (1.42 NA and 1.65 NA) microscope(More)
The optical properties of coupled metallic nanorods are studied to investigate the use of coupled plasmonic structures in field-enhanced spectroscopies. Light scattering by coupled nanorods is calculated with the boundary element method, including retardation. The modes of coupled nanorod systems are calculated by the boundary charge method and discussed in(More)
This is the second in a series of articles describing a wide variety of projects at NIST that synergistically combine physical science and information science. It describes, through examples, how the Scientific Applications and Visualization Group (SAVG) at NIST has utilized high performance parallel computing, visualization, and machine learning to(More)
Photonic structures made from square arrays of air holes in Si(3)N(x) membranes are locally imaged by near-field optical microscopy in illumination mode. Holes with diameters smaller than and larger than the wavelength of light are investigated. Counterintuitively, the holes appear dark and the film is bright in transmission images for both hole sizes.(More)
Two cases are illustrated to demonstrate the importance of occupation, in the form of viola playing, in the aetiology of myofascial pain dysfunction. An understanding of the contribution of tension and playing style, together with physical limitations, is emphasised and, consequently, it is acknowledged that modification may be necessary to the formulation(More)