44 research outputs found
Free-Space Graphics with Electrically Driven Levitated Light Scatterers
Levitation of optical scatterers provides a new mean to develop free-space
volumetric displays. The principle is to illuminate a levitating particle
displaced at high velocity in three dimensions (3D) to create images based on
persistence of vision (POV). Light scattered by the particle can be observed
all around the volumetric display and therefore provides a true 3D image that
does not rely on interference effects and remains insensitive to the angle of
observation. The challenge is to control with a high accuracy and at high speed
the trajectory of the particle in three dimensions. Systems that use light to
generate free-space images either in plasma or with a bead are strictly
dependent of the scanning method used. Mechanical systems are required to scan
the particles in the volume which weakens the time dynamics. Here we use
electrically driven planar Paul traps (PPTs) to control the trajectory of
electrically charged particles. A single gold particle colloid is manipulated
in three dimensions through AC and DC electrical voltages applied to a PPT.
Electric voltages can be modulated at high frequencies (150 kHz) and allow for
a high speed displacement of particles without moving any other system
component. The optical scattering of the particle in levitation yields
free-space images that are imaged with conventional optics. The trajectory of
the particle is entirely encoded in the electric voltage and driven through
stationary planar electrodes. We show in this paper, the proof-of-concept for
the generation of 3D free space graphics with a single electrically scanned
particle
Long distance manipulation of a levitated nanoparticle in high vacuum
Accurate delivery of small targets in high vacuum is a pivotal task in many
branches of science and technology. Beyond the different strategies developed
for atoms, proteins, macroscopic clusters and pellets, the manipulation of
neutral particles over macroscopic distances still poses a formidable
challenge. Here we report a novel approach based on a mobile optical trap
operated under feedback control that enables long range 3D manipulation of a
silica nanoparticle in high vacuum. We apply this technique to load a single
nanoparticle into a high-finesse optical cavity through a load-lock vacuum
system. We foresee our scheme to benefit the field of optomechanics with
levitating nano-objects as well as ultrasensitive detection and monitoring.Comment: 12 pages 5 figure
In-plane remote photoluminescence excitation of carbon nanotube by propagating surface plasmon
In this work, we demonstrate propagating surface plasmon polariton (SPP) coupled photoluminescence (PL) excitation of single-walled carbon nanotube (SWNT). SPPs were launched at a few micrometers from individually marked SWNT, and plasmon-coupled PL was recorded to determine the efficiency of this remote in-plane addressing scheme. The efficiency depends upon the following factors: (i) longitudinal and transverse distances between the SPP launching site and the location of the SWNT and (ii) orientation of the SWNT with respect to the plasmon propagation wave vector (k SPP). Our experiment explores the possible integration of carbon nanotubes as a plasmon sensor in plasmonic and nanophotonic devices
Does the market value the affiliation of French firms with the UN Global Compact
The UN Global Compact Leaders Summit held in New York on June 2010 marked the 10th anniversary of the UN Global Compact (Adams and Petrella, 2010). From its humble beginnings in 2000, the Global Compact has grown to encompass more than 8,700 corporate participants and others stakeholders, including over 7,700 businesses from 130 countries around the world. It is the world’s largest voluntary corporate responsibility initiative. The benefits for companies voluntarily affiliating with the UN Global Compact have been little documented from an empirical perspective. This affiliation is on a voluntary basis, which raises questions about the integration of this information by capital markets. This study attempts to address these questions, drawing on a sample of French companies listed on the SBF 250 index. Results suggest that, in the French context, investors do not significantly value firm's affiliation with the UN Global Compact
Spontaneous hot-electron light emission from electron-fed optical antennas
Nanoscale electronics and photonics are among the most promising research
areas providing functional nano-components for data transfer and signal
processing. By adopting metal-based optical antennas as a disruptive
technological vehicle, we demonstrate that these two device-generating
technologies can be interfaced to create an electronically-driven self-emitting
unit. This nanoscale plasmonic transmitter operates by injecting electrons in a
contacted tunneling antenna feedgap. Under certain operating conditions, we
show that the antenna enters a highly nonlinear regime in which the energy of
the emitted photons exceeds the quantum limit imposed by the applied bias. We
propose a model based upon the spontaneous emission of hot electrons that
correctly reproduces the experimental findings. The electron-fed optical
antennas described here are critical devices for interfacing electrons and
photons, enabling thus the development of optical transceivers for on-chip
wireless broadcasting of information at the nanoscale
Two-Color Dark-Field (TCDF) microscopy for metal nanoparticles imaging inside cells
Noble metal nanoparticles (NPs) supporting localized surface plasmon resonances are widely
used in the context of biotechnology as optical and absorption contrast agents with great potential
applicability to both diagnostics and less invasive therapies. In this framework, it is crucial to have
access to simple and reliable microscopy techniques to monitor the NPs that have internalized
into cells. While dark field (DF) microscopy takes advantage of the enhanced NPs scattering at
their plasmon resonance, its use in cells is limited by the large scattering background from the
internal cell compartments. Here, we report on a novel two-color dark field microscopy that addresses
these limitations by significantly reducing the cell scattering contribution. We first present
the technique and demonstrate its enhanced contrast, specificity and reliability for NP detection
compared to standard optical dark field. We then demonstrate its potential suitability in two different
settings, namely wide-field parallel screening of circulating cells in microfluidic chip and
high-resolution tracking of internalized NPs in cells. These proof of principle experiments show a
promising capability of this approach with possible extension to other kinds of targeted systems
like bacteria and vesicles.Peer ReviewedPostprint (author's final draft