arXiv subjects

S. Huant

Publications and source records attributed to S. Huant.

40 records · Page 3Linked to original sources

arXiv2006

Remote optical addressing of single nano-objects

We present a scheme for remotely addressing single nano-objects by means of near-field optical microscopy that makes only use of one of the most fundamental properties of electromagnetic radiation: its polarization. A medium containing optically active nano-objects is covered with a thin metallic film presenting sub-wavelength holes. When the optical tip is positioned some distance away from a hole, surface plasmons in the metal coating are generated which, by turning the polarization plane of the excitation light, transfer the excitation towards a chosen hole and induce emission from the underlying nano-objects. The method, easily applicable to other systems, is demonstrated for single quantum dots (QDs) at low temperature. It may become a valuable tool for future optical applications in the nanoworld.

physics.optics↗

arXiv2006

CdSe-single-nanoparticle based active tips for near-field optical microscopy

We present a method to realize active optical tips for use in near-field optics that can operate at room temperature. A metal-coated optical tip is covered with a thin polymer layer stained with CdSe nanocrystals or nanorods at low density. The time analysis of the emission rate and emission spectra of the active tips reveal that a very small number of particles - possibly down to only one - can be made active at the tip apex. This opens the way to near-field optics with a single inorganic nanoparticle as a light source.

physics.optics↗

arXiv2006

Imaging and controlling electron transport inside a quantum ring

Traditionally, the understanding of quantum transport, coherent and ballistic1, relies on the measurement of macroscopic properties such as the conductance. While powerful when coupled to statistical theories, this approach cannot provide a detailed image of "how electrons behave down there". Ideally, understanding transport at the nanoscale would require tracking each electron inside the nano-device. Significant progress towards this goal was obtained by combining Scanning Probe Microscopy (SPM) with transport measurements2-7. Some studies even showed signatures of quantum transport in the surrounding of nanostructures4-6. Here, SPM is used to probe electron propagation inside an open quantum ring exhibiting the archetype of electron wave interference phenomena: the Aharonov-Bohm effect8. Conductance maps recorded while scanning the biased tip of a cryogenic atomic force microscope above the quantum ring show that the propagation of electrons, both coherent and ballistic, can be investigated in situ, and even be controlled by tuning the tip potential.

cond-mat.mes-hall↗

arXiv1996

Dynamics in the dimerised and high field incommensurate phase of CuGeO$_3$

Temperature ($2.3<T<40$\ K) and magnetic field ($0<B<17$\ T) dependent far infrared absorption spectroscopy on the spin-Peierls coumpound CuGeO$_3$\ has revealed several new absorption processes in both the dimerised and high field phase of CuGeO$_3$. These results are discussed in terms of the modulation of the CuGeO$_3$\ structure. At low fields this is the well known spin-Peierls dimerisation. At high fields the data strongly suggests a field dependent incommensurate modulation of the lattice as well as of the spin structure.

cond-mat↗