arXiv subjects

Serge Huant

Publications and source records attributed to Serge Huant.

28 records · Page 2Linked to original sources

arXiv2014

Plasmon scattering from holes: from single hole scattering to Young's experiment

In this article, the scattering of surface plasmon polaritons (SPPs) into photons at holes is investigated. A local, electrically excited source of SPPs using a scanning tunnelling microscope (STM) produces an outgoing circular plasmon wave on a thick (200 nm) gold film on glass containing holes of 250, 500 and 1000 nm diameter. Fourier plane images of the photons from hole-scattered plasmons show that the larger the hole diameter, the more directional the scattered radiation. These results are confirmed by a model where the hole is considered as a distribution of horizontal dipoles whose relative amplitudes, directions, and phases depend linearly on the local SPP electric field. An SPP-Young's experiment is also performed, where the STM-excited SPP-wave is incident on a pair of 1 $μ$m diameter holes in the thick gold film. The visibility of the resulting fringes in the Fourier plane is analyzed to show that the polarization of the electric field is maintained when SPPs scatter into photons. From this SPP-Young's experiment, an upper bound of $\approx$ 200 nm for the radius of this STM-excited source of surface plasmon polaritons is determined.

physics.optics↗

arXiv2014

Transmission and reflection characteristics of metal-coated optical fiber tip pairs

The optical transmission and reflection in between two metalized optical fiber tips is studied in the optical near-field and far-field domains. Besides aluminum-coated tips for near-field scanning optical microscopy (NSOM), specifically developed gold-coated fiber tips cut by focused ion beam (FIB) are investigated. Transverse transmission maps of sub-wavelength width clearly evidence optical near-field coupling between the tips for short tip distances and becomes essentially Gaussian-shaped for larger distances in the far-field regime. Moreover concentric reflection fringes observed for NSOM-type tips illustrate the influence of the receiving fiber tip on the emission pattern of the source tip.

physics.optics↗

arXiv2013

Single and dual fiber nano-tip optical tweezers: trapping and analysis

An original optical tweezers using one or two chemically etched fiber nano-tips is developed. We demonstrate optical trapping of 1 micrometer polystyrene spheres at optical powers down to 2 mW. Harmonic trap potentials were found in the case of dual fiber tweezers by analyzing the trapped particle position fluctuations. The trap stiffness was deduced using three different models. Consistent values of up to 1 fN/nm were found. The stiffness linearly decreases with decreasing light intensity and increasing fiber tip-to-tip distance.

physics.optics↗

arXiv2013

YAG nano-light sources with high Ce concentration

We investigate the luminescence properties of 10 nm YAG nanoparticles doped with Ce ions at 0.2%, 4% and 13% that are designed as active probes for Scanning Near field Optical Microscopy. They are produced by a physical method without any subsequent treatment, which is imposed by the desired application. The structural analysis reveals the amorphous nature of the particles, which we relate to some compositional defect as indicated by the elemental analysis. The optimum emission is obtained with a doping level of 4%. The emission of the YAG nanoparticles doped at 0.2% is strongly perturbed by the crystalline disorder whereas the 13% doped particles hardly exhibit any luminescence. In the latter case, the presence of Ce4+ ions is confirmed, indicating that the Ce concentration is too high to be incorporated efficiently in YAG nanoparticles in the trivalent state. By a unique procedure combining cathodoluminescence and Rutherford backscattering spectrometry, we demonstrate that the enhancement of the particles luminescence yield is not proportional to the doping concentration, the emission enhancement being larger than the Ce concentration increase. Time-resolved photoluminescence reveals the presence of quenching centres likely related to the crystalline disorder as well as the presence of two distinct Ce ions populations. Eventually, nano-cathodoluminescence indicates that the emission and therefore the distribution of the doping Ce ions and of the defects are homogeneous.

cond-mat.mes-hall↗

arXiv2012

A new transport phenomenon in nanostructures: A mesoscopic analog of the Braess paradox encountered in road networks

The Braess paradox, known for traffic and other classical networks, lies in the fact that adding a new route to a congested network in an attempt to relieve congestion can counter-intuitively degrade the overall network performance. Recently, we have extended the concept of Braess paradox to semiconductor mesoscopic networks, whose transport properties are governed by quantum physics. In this paper, we demonstrate theoretically that, alike in classical systems, congestion plays a key role in the occurrence of a Braess paradox in mesoscopic networks.

cond-mat.mes-hall↗

arXiv2011

On the imaging of electron transport in semiconductor quantum structures by scanning-gate microscopy: successes and limitations

This paper presents a brief review of scanning-gate microscopy applied to the imaging of electron transport in buried semiconductor quantum structures. After an introduction to the technique and to some of its practical issues, we summarise a selection of its successful achievements found in the literature, including our own research. The latter focuses on the imaging of GaInAs-based quantum rings both in the low magnetic field Aharonov-Bohm regime and in the high-field quantum Hall regime. Based on our own experience, we then discuss in detail some of the limitations of scanning-gate microscopy. These include possible tip induced artefacts, effects of a large bias applied to the scanning tip, as well as consequences of unwanted charge traps on the conductance maps. We emphasize how special care must be paid in interpreting these scanning-gate images.

cond-mat.mes-hall↗

arXiv2011

A fibered interference scanning optical microscope for living cell imaging

We report on the 3-dimensional imaging of biological cells including living neurons by a recently developed fibered interferometric Scanning Optical Microscope. The topography and surface structure of mouse fibroblasts and hippocampal neurons are clearly revealed. This straightforward technique allows fast, high resolution observation of samples in liquids without lengthy alignment procedures or costly components.

physics.optics↗

arXiv2010

`Deterministic' quantum plasmonics

We demonstrate `deterministic' launching of propagative quantum surface-plasmon polaritons at freely chosen positions on gold plasmonic receptacles. This is achieved by using as plasmon launcher a near-field scanning optical source made of a diamond nanocrystal with two Nitrogen-Vacancy color-center occupancy. Our demonstration relies on leakage-radiation microscopy of a thin homogeneous gold film and on near-field optical microscopy of a nanostructured thick gold film. Our work paves the way to future fundamental studies and applications in quantum plasmonics that require an accurate positioning of single-plasmon sources and may open a new branch in plasmonics and nanophotonics, namely scanning quantum plasmonics.

cond-mat.mes-hall↗

arXiv2010

Can nanotechnology experimentally solve the plane-plane challenge

Non-contact interaction between two parallel flat surfaces is a central paradigm in sciences. This situation is the starting point for a wealth of different models: the capacitor description in electrostatics, hydrodynamic flow, thermal exchange, the Casimir force, direct contact study, third body confinement such as liquids or films of soft condensed matter. The control of parallelism is so demanding that no versatile single force machine in this geometry has been proposed so far. Using a combination of nanopositioning based on inertial motors and microcrystal shaping with Focused Ion Beams (FIB) we propose here an experimental set up that should enable one to measure interactions between movable surfaces separated by gaps in the micrometer and the nanometer ranges.

physics.ins-det↗

arXiv2007

25-nm diamond crystals hosting single NV color centers sorted by photon-correlation near-field microscopy

Diamond nanocrystals containing highly photoluminescent color centers are attractive non-classical and near-field light sources. For near-field applications the size of the nanocrystal is crucial since it defines the optical resolution. NV (Nitrogen-Vacancy) color centers are efficiently created by proton irradiation and annealing of a nanodiamond powder. Using near-field microscopy and photon statistics measurements, we show that nanodiamond with size down to 25 nm can hold a single NV color center with bright and stable photoluminescence.

cond-mat.mtrl-sci↗