High-permittivity dielectric particles with resonant magnetic properties are being explored as constitutive elements of new metamaterials and devices. Magnetic properties of low-loss dielectric nanoparticles in the visible or infrared are not expected due to intrinsic low refractive index of optical media in these regimes. Here we analyze the dipolar electric and magnetic response of lossless dielectric spheres made of moderate permittivity materials. For low material refractive index (<∼3) there are no sharp resonances due to strong overlapping between different multipole contributions. However, we find that Silicon particles with index of refraction∼3.5 and radius∼200 nm present strong electric and magnetic dipolar resonances in telecom and near-infrared frequencies, (i.e. at wavelengths≈1.2-2 mm) without spectral overlap with quadrupolar and higher order resonances. The light scattered by these Si particles can then be perfectly described by dipolar electric and magnetic fields.

We show that submicrometer silicon spheres, whose polarizabilities are completely given by their two first Mie coefficients, are an excellent laboratory to test effects of both angle-suppressed and resonant differential scattering cross sections. Specifically, outstanding scattering angular distributions, with zero forward- or backward-scattered intensity, (i.e., the so-called Kerker conditions), previously discussed for hypothetical magnetodielectric particles, are now observed for those Si objects in the near infrared. Interesting new consequences for the corresponding optical forces are derived from the interplay, both in and out of resonance, between the electric- and magnetic-induced dipoles.

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Abstract-We present a compact physics-based model for the nanoscale gate-all-around MOSFET working in the ballistic limit. The current through the device is obtained by means of the Landauer approach, being the barrier height the key parameter in the model. The exact solution of the Poisson's equation is obtained in order to deal with all the operation regions tracing properly the transitions between them.

Optical nanoprobes, designed to emit or collect light in the close proximity of a sample, have been extensively used to sense and image at nanometer resolution. However, the available nanoprobes, constructed from artificial materials, are incompatible and invasive when interfacing with biological systems. In this work, we report a fully biocompatible nanoprobe for subwavelength probing of localized fluorescence from leukemia single-cells in human blood. The bioprobe is built on a tapered fiber tip apex by optical trapping of a yeast cell (1.4 μm radius) and a chain of Lactobacillus acidophilus cells (2 μm length and 200 nm radius), which act as a high-aspect-ratio nanospear. Light propagating along the bionanospear can be focused into a spot with a full width at half-maximum (fwhm) of 190 nm on the surface of single cells. Fluorescence signals are detected in real time at subwavelength spatial resolution. These noninvasive and biocompatible optical probes will find applications in imaging and manipulation of biospecimens.