Search results for "SCOPE"
showing 10 items of 2420 documents
Actively mode-locked fibre ring laser based on in-fibre acousto-optic amplitude modulation
2011
Recent advances in the development of all-fibre amplitude modulators have led to the implementation of a series of different actively mode-locked fibre lasers [1–4]. In-fibre acousto-optic modulation based on intermodal coupling induced my a standing flexural acoustic wave permits the implementation of broad bandwidth (1.5 nm), high modulation depth (0.72), low-insertion-loss (0.75 dB) all-fibre amplitude modulators that operate in the MHz frequency range. The experimental characterization of a laser with the configuration depicted in Fig. 1 (a) as a function of the radio frequency voltage that controls the modulator (see Fig. 1 (b)), the length of the Erbium doped fibre (EDF), and the opti…
Imaging of photonic nanopatterns by scanning near-field optical microscopy
2002
We define photonic nanopatterns of a sample as images recorded by scanning near-field optical microscopy with a locally excited electric dipole as a probe. This photonic nanopattern can be calculated by use of the Green’s dyadic technique. Here, we show that scanning near-field optical microscopy images of well-defined gold triangles taken with the tetrahedral tip as a probe show a close similarity to the photonic nanopattern of this nanostructure with an electric dipole at a distance of 15 nm to the sample and tilted 45° with respect to the scanning plane.
Crystal growth of Hg1−xMnxSe for infrared detection
2007
In this work, we report on the successfully growing Hg"1"-"xMn"xSe bulk crystals using a mixed, travelling heater method and Bridgman method, two-step procedure. Firstly, and with the aim of reducing Hg high pressure related to the high temperature synthesis reaction between the components in elemental form, HgSe crystals were synthesized and grown by the cold travelling heater method. Secondly, previously sublimated Mn and Se were incorporated to complete the desired composition. Then, the Bridgman growth was carried out by heating the alloy at a temperature of about 880^oC and lowering it at rate of 1mm/h through a gradient of 25^oC/cm. The Hg"1"-"xMn"xSe crystals were characterized by sc…
Analysis of static friction and elastic forces in a nanowire bent on a flat surface: A comparative study
2014
ZnO nanowires bent to a complex shape and held in place by static friction force from supporting flat surface are investigated experimentally and theoretically. The complex shapes are obtained by bending the nanowires inside a scanning electron microscope with a sharp tip attached to a nanopositioner. Several methods previously described in the literature are applied along with author's original method to calculate the distributed friction force and stored elastic energy in the nanowires from the bending profile. This comparative study evidences the importance of the usage of appropriate models for accurate analysis of the nanowires profile. It is demonstrated that incomplete models can lea…
Structural characterization of relaxor ferroelectric PbMg 1/3 Nb 2/3 O 3 -PbTiO 3 thin film heterostructures deposited by pulsed laser ablation
2000
Highly oriented and epitaxial films of relaxor ferroelectric PbMg1/3Nb2/3O3-PbTiO3 (PMN-PT) with a composition (68/32) near the morphotropic phase boundary were deposited by pulsed laser ablation on La0.5Sr0.5CoO3 bottom electrodes, deposited on MgO (100) and LaAlO3 (100). The formation of crystalline phases, epitaxy, film–electrode–substrate orientation relationships and crystal perfection were studied by X-ray diffraction and scanning electron microscopy. The structural properties were found to depend on the deposition conditions and substrate. Correlation of both the dielectric and relaxor properties in the heterostructures and the structural properties of the PMN-PT films was observed.
Multimodal nonlinear imaging of suspended carbon nanotubes using circular polarizations
2013
In this work, multimodal nonlinear microscopy of suspended CNTs using circular polarizations (CP) was reported. Significant variations in the SHG and THG signals of the CNTs between left hand circular polarization (LHCP) and right hand circular polarization (RHCP) were observed. The variations in the nonlinear signals can be associated to the unique properties of the CNTs such as chirality.
Narrowing the Plasmonic Sensitivity Distribution by Considering the Individual Size of Gold Nanorods
2018
The plasmonic nanoparticle sensitivity, sensing volume, and the signal-to-noise ratio are strongly dependent on the nanoparticle dimensions. It is difficult to chemically produce or purify nanoparticles with a size variation of less than 10%. This size variation induces a systematic error in sensing experiments that can be reduced when the exact size of each individual nanoparticle is known. In this work, we show how the size of gold nanorods can be estimated directly from the optical spectra of single nanoparticles by using the increase of radiation damping with the nanoparticle size. We verify our approach by comparing these spectrally estimated sizes with the precise sizes of exactly the…
Wideband tuning of four-wave mixing in solid-core liquid-filled photonic crystal fibers
2016
We present an experimental study of parametric four-wave mixing generation in photonic crystal fibers that have been infiltrated with ethanol. A silica photonic crystal fiber was designed to have the proper dispersion properties after ethanol infiltration for the generation of widely spaced four-wave mixing (FWM) bands under 1064 nm pumping. We demonstrate that the FWM bands can be tuned in a wide wavelength range through the thermo-optic effect. Band shifts of 175 and over 500 nm for the signal and idler bands, respectively, are reported. The reported results can be of interest in many applications, such as CARS microscopy.
Ultrafast laser-induced micro-explosion: material modification tool
2016
Femtosecond Bessel pulses with a needle-like intensity distribution were focused inside sapphire crystal to create voids and the shock-wave affected volume which is by more than two orders of magnitude larger as compared with that made by the Gaussian pulse.
Four Wave Mixing in Photonic Crystal Fibers:<br /> Tuning Techniques
2016
We present an experimental and numerical study of four-wave mixing in photonic crystal fibers. Our objective is the development of tuning techniques based on tailoring de dispersion of the fibers. We demonstrate wide tuning ranges.