Search results for "Ion microscopy"
showing 10 items of 91 documents
Contrôle de nano-antennes optiques par une commande électrique : tuner plasmonique et transduction
2011
Optical nano-antennae are the new class of components to control light/matterinteraction at the nanoscale. These devices are operating in the visible to near infraredpart of the spectrum. The properties of these nano objects are controlled by theform, the size and the material.In the radio frequency domain, the tuner changes dynamically the operatingwavelength of the antenna. In this thesis work, we search to transfer this conceptto the nanoscale. The principle is to change the load impedance of the antenna, i.e.changing the optical index of the dielectric medium around the nano-object. Forthat we used anisotropic liquid cristal molecules. The value of the optical index iscontrolled by appl…
Fabrication and characterization of thermo-plasmonic routers for telecom applications
2013
The Dielectric Loaded Surface Plasmon Polariton Waveguides (DLSPPWs) have recently emerged as a possible solution to carry both optical and electrical signals on- chip. However, in the particular context of optical interconnects, advanced functionalities such as filtering, switching, and routing are required in order to replace in the future the equivalent electronic components which are too much power consumer and also to reduce their footprints. After presenting the interest and limitation of the leakage radiation microscopy method used all along this work, we show several active devices using thermo-sensitive polymers as the dielectric load driven electrically by Joule heating. Then we d…
Superresolution imaging of biological nanostructures by spectral precision distance microscopy
2011
For the improved understanding of biological systems on the nanoscale, it is necessary to enhance the resolution of light microscopy in the visible wavelength range beyond the limits of conventional epifluorescence microscopy (optical resolution of about 200 nm laterally, 600 nm axially). Recently, various far-field methods have been developed allowing a substantial increase of resolution ("superresolution microscopy", or "lightoptical nanoscopy"). This opens an avenue to 'nano-image' intact and even living cells, as well as other biostructures like viruses, down to the molecular detail. Thus, it is possible to combine light optical spatial nanoscale information with ultrastructure analyses…
Superconducting properties of in-plane W-C nanowires grown by He+ Focused Ion Beam Induced Deposition
2021
Focused ion beam induced deposition (FIBID) is a nanopatterning technique that uses a focused beam of charged ions to decompose a gaseous precursor. So far, the flexible patterning capabilities of FIBID have been widely exploited in the fabrication of superconducting nanostructures, using the W(CO)6 precursor mostly in combination with a focused beam of Ga+ ions. Here, the fabrication and characterization of superconducting in-plane tungsten-carbon (W-C) nanostructures by He+ FIBID of the W(CO)6 precursor is reported. A patterning resolution of 10 nm has been achieved, which is virtually unattainable for Ga+ FIBID. When the nanowires are patterned with widths of 20 nm and above, the deposit…
Formation of ZnO nanowires by anodization under hydrodynamic conditions for photoelectrochemical water splitting
2020
[EN] The present work studies the influence of hydrodynamic conditions (from 0 to 5000 rpm) during Zn anodization process on the morphology, structure and photoelectrocatalytic behavior of ZnO nanostructures. For this purpose, analysis with Confocal Laser-Raman Spectroscopy, Field Emission Scanning Electron Microscope (FE-SEM) and photoelectrochemical water splitting tests were performed. This investigation reveals that hydrodynamic conditions during anodization promoted the formation of ordered ZnO nanowires along the surface that greatly enhance its stability and increases the photocurrent density response for water splitting in a 159% at the 5000 rpm electrode rotation speed.
Angular and lateral spreading of ion beams in biomedical nuclear microscopy
2009
Abstract Nuclear scattering from target atoms gives rise to a spatial broadening of energetic ion beams penetrating matter. The spatial broadening of the ion beam presents an ultimate limit to the resolving power that can be achieved in nuclear microscopy methods. The pressing of the attainable resolution limit in biomedical nuclear microscopy to dimensions approaching 10 nm, or so, implies the fundamental limitation from ion-target scattering will become increasingly significant. This effect has been investigated by a combined analytical and numerical computational approach to determine the extent and how single and multiple scattering processes limit the resolution for analysis with 2 MeV…
Thin film growth into the ion track structures in polyimide by atomic layer deposition
2017
Abstract High-aspect ratio porous structures with controllable pore diameters and without a stiff substrate can be fabricated using the ion track technique. Atomic layer deposition is an ideal technique for depositing thin films and functional surfaces on complicated 3D structures due to the high conformality of the films. In this work, we studied Al2O3 and TiO2 films grown by ALD on pristine polyimide (Kapton HN) membranes as well as polyimide membranes etched in sodium hypochlorite (NaOCl) and boric acid (BO3) solution by means of RBS, PIXE, SEM-EDX and helium ion microcopy (HIM). The focus was on the first ALD growth cycles. The areal density of Al2O3 film in the 400 cycle sample was det…
Confocal and Two-Photon Spectroscopy
2021
The spectroscopic analysis of bulk samples provides useful information at the mesoscopic scale that can be fostered when coupled with microscopy, which allows to integrate the spatial information in the analysis, this being of utmost importance for non‐homogeneous samples. Technologies such as confocal and two‐photon microscopy quickly became mainstream methods as they provide the possibility of noninvasive real‐time analysis of specimens of different nature, eliciting specific features even in samples with non‐ergodic behaviour. The spatial resolution of optical microscopy has its roots in the diffraction of light on the objective lens of the imaging system. Fluorescence microscopy is an o…
Improvement of two-dimensional structured illumination microscopy with an incoherent illumination pattern of tunable frequency.
2018
In two-dimensional structured illumination microscopy (2D-SIM), high-resolution images with optimal optical sectioning (OS) cannot be obtained simultaneously. This tradeoff can be overcome by using a tunable-frequency 2D-SIM system and a proper reconstruction method. The goal of this work is twofold. First, we present a computational approach to reconstruct optical-sectioned images with super-resolution enhancement (OS-SR) by using a tunable SIM system. Second, we propose an incoherent tunable-frequency 2D-SIM system based on a Fresnel biprism implementation. Integration of the proposed computational method with this tunable structured illumination (SI) system results in a new 2D-SIM system…
Optimal design of incoherent tunable-frequency structured illumination microscope scheme
2018
Structured illumination microscopy (SIM) improves resolution and optical sectioning capability compared to conventional widefield techniques. The main idea of this method is the illumination of the sample with a structured pattern of fixed spatial modulation frequency. Previously, a Fresnel biprism has been implemented in a structured illumination (SI) device providing tunable-frequency sinusoidal patterns. However, the use of this SI system introduces a tradeoff between the visibility and field of view of the illumination fringes. In this contribution, we analyze theoretically this tradeoff and propose the optimal design for the Fresnel biprism-based SIM system.