Search results for "Microscope"

Controlling Light Confinement by Excitation of Localized Surface Plasmons

2007

Localized surface plasmons can be used to control near-field optical phenomena in the subwavelength range. Specifically, this chaper reviews recent results which show that localized surface plasmons can confine the optical intensity down to nanoscopic dimensions. The discussion first considers how a collection-mode near-field optical microscope can observe the squeezing of the plasmon field of metallic nanostructures deposited on a flat surface. Numerical simulations then provide illustrations of the confined fields associated with nanostructures which are feasible using current microfabrication techniques. Finally, we present arguments which explain how localized surface plasmons can deliv…

Mapping surface plasmon propagation by collection-mode near-field microscopy

2011

Surface plasmon propagation along striped Gold structures has been investigated by collection-mode near-field microscopy, leading to map the field intensity at the structure surface and to assess the system behavior at the nanoscale.

Near-field characterization of plasmon polariton propagation along periodically nano-structured metal thin films

2007

We operate a near-field optical microscope to investigate the properties of periodically nano-structured metal thin films designed to control at the micron scale the propagation or the excitation of surface plasmon polaritons.

All-optical and electro-optical active plasmonic telecom components

2011

Active plasmonics is an attractive emerging field in which the ability to control the surface plasmon polariton (SPP) propagation finds many applications such as realization of fully functional integrated photonic circuitry. We demonstrate both numerically and experimentally switching of the SPP transmission based on two different approaches namely the all-optical and electro-optical at telecom wavelengths. The plasmonic component consists of a compact and efficient SPP switch utilizing highly sensitive ring resonator which has high sensitivity to the refractive index changes. Fabrication was done via e-beam lithography utilizing advanced proximity corrections. The compenents were character…

Surface plasmon polariton propagation across a gentle silver step

2001

Abstract Surface plasmon polaritons (SPPs) are excited with light of wavelength λ1=632.8 nm on or near a gentle Ag/Ag step structure using focused beam, prism coupling and detected using a bare, sharpened fibre tip. The tip–sample separation is controlled by means of an evanescent optical field at wavelength λ2=543.5 nm in a photon scanning tunnelling microscope (PSTM). The SPP propagation properties are first characterised on both the thin and thick sections of the Ag film structure either side of the step, both macroscopically, using attenuated total reflection, and microscopically from the PSTM images; the two techniques yield very good agreement. It is found that the SPP propagation len…

Space-time features of THz emission from optical rectification in sub-wavelength areas

2011

We present our investigation on the THz space-time emission characteristic induced by the non-paraxial generation regime in highly localized THz generation via optical rectification on sub-wavelength areas.

Emission Electron Microscopy of Nanoparticles in Strong fs Laser Fields

2003

Heteroepitaxial growth of Co on W(110) investigated by scanning tunneling microscopy

2003

We investigated the growth of Co submonolayers on bcc W(110) by scanning tunneling microscopy. Due to the strong Co-W bonding, monolayers of Co grow in equilibrium pseudomorphically on W(110) until the monolayer is almost completed. When excess atoms are deposited atop the pseudomorphic monolayer, it transforms to a close-packed (cp) monolayer with misfit dislocation lines parallel to $[11\ifmmode\bar\else\textasciimacron\fi{}0]$ (Nishiyama-Wassermann orientation). The structure of the cp monolayer, as concluded from atomically resolved STM images, deviates from the rigid hard-sphere model of a cp (111) layer. Details of the structure are compared to a structure model previously proposed by…

Does mechanical locking-base ceramic brackets reduce cracks at debonding?

2012

Objectives: Debonding of chemically bonded ceramic brackets has been mostly led to enamel damages. This study aimed to evaluate enamel cracks followed by debonding ceramic brackets with mechanical retention. Study Design: Sixty extracted human premolar teeth were randomly divided into two groups. Metallic brackets and recently available ceramic brackets with mechanical retention were bonded to the teeth in first (MB) and second (CB) group respectively. After a week, the brackets were debonded using a pair of bracket-removing pliers assembled to a testing machine. Optical stereomicroscope and trans-illumination techniques were used to calculate the cracks and measure their length before bond…

Surface properties of AlInGaN/GaN heterostructure

2016

Abstract Surface structural, electronic and electrical properties of the quaternary alloy AlInGaN/GaN heterostructures are investigated. Surface termination, atomic arrangement, electronic and electrical properties of the (0001) surface and (10–11) V-defect facets have been experimentally analyzed using various surface sensitive techniques including spectroscopy and microscopy. Moreover, the effect of sub-band gap (of the barrier layer) illumination on contact potential difference (VCPD) and the role of oxygen chemisorption have been studied.