Building optical matter with binding and trapping forces

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Comparison of two illumination modes for wide-field optical coherence tomography has revealed that spatially coherent illumination generates coherent cross talk, causing significant image degradation, and that spatially incoherent illumination, with an adequate interferometer design, provides an efficient mechanism for suppression of coherent cross talk. This is shown by comparison of a pulsed laser with a thermal light source for a U.S. Air Force resolution target covered with a scattering solution made fr

By angle-resolved photoemission spectroscopy and polarization-dependent infrared reflectivity measurements the electronic and vibrational properties of the low-dimensional perovskites Sr1-yLayNbO3.5-x were studied along different crystal directions. The electronic behavior strongly depends on the oxygen and La content, including quasi-one-dimensional metallic and ferroelectric insulating behavior. An extremely small energy gap at the Fermi level is found for SrNbO3.41 and SrNbO3.45 along the conducting dire

In this paper we describe the fabrication of a two-dimensional photonic band gap structure by focused electron beam induced deposition. Structure geometry is computed in order to create a light-trapping effect at 632 nm wavelength. Deposits produced using tetraethyl orthosilicate (SiO4C8H20) as precursor were studied to determine their chemical composition and geometrical dimensions. The deposited material has a refractive index ~n ¼ 1:85 þ i3:9 � 10�4 at 632 nm. Transmission electron microscopy revealed

Geant4 is a toolkit for simulating the passage of particles through matter. It includes a complete range of functionality including tracking, geometry, physics models and hits. The physics processes offered cover a comprehensive range, including electromagnetic, hadronic and optical processes, a large set of long-lived particles, materials and elements, over a wide energy range starting, in some cases, from 250 eV and extending in others to the TeV energy range. It has been designed and constructed to expos

We present a new, robust algorithm for tracking fluorescent particles in dynamic image sequences obtained by brightfield or confocal microscopy. Specifically, we consider the problem of extracting the movement of chromosomal telomeres within the nucleus of a budding yeast cell. Our method has three components. The first is an alignment module that compensates for the movement of the biological structure under investigation. In our application, the images are aligned to the center of gravity of the nucleus w

Climate changes and global warming are generally associated with the enhanced greenhouse effect, but aerosols can induce a cooling effect and thus regionally mask this warming effect. Unfortunately, the strong variability both in space and in time of the aerosols and thus the difficulty to characterize their global basic properties induce large uncertainties in the predictions of the numerical models. Those uncertainties are as high as the absolute level of the enhanced greenhouse forcing. To solve this pro

Experimental demonstration of optical speedup at transparency (OSAT) has been performed on a 1 mm long semiconductor optical amplifiers (SOA). OSAT is a recently proposed scheme that decreases the recovery time of an SOA while maintaining the available gain. It is achieved by externally injecting into the SOA the beam of a separate high power laser at energies around the transparency point. Even though the experimental conditions were not optimal, a beam of 100 mW decreases the recovery time by a third when

We present a new technique for computing the electromagnetic field that propagates and is scattered in three-dimensional structures formed by bodies embedded in a stratified background. This fully vectorial technique is based on the Green's tensor associated with the stratified background. Its advantage lies in the fact that only the scatterers must be discretized, the stratified background being accounted for in the Green's tensor. Further, the boundary conditions at the different material interfaces as we

Steady-state and picosecond (ps) fluorescence studies of wild-type bacteriorhodopsin (wt-bR) and of a nonisomerizing analog locked in the all-trans configuration have been performed. Extending earlier work done by femtosecond absorption spectroscopy, we observe a strong similarity between both proteins in both fluorescence spectra and Stokes shift thus confirming the previous result that the fluorescent state I460 of the native bR proteins is in the all-trans configuration. Comparison of the spectra of fluo

Crystal damage induced by irradiation is investigated using transmission electron microscopy (TEM) coupled to molecular dynamics (MD) calculations. The displacement cascades are simulated for energies ranging from 10 to 50 keV in Al, Ni and Cu and for times of up to a few tens of picoseconds. Samples are then used to perform simulations of the TEM images that one could observe experimentally. Diffraction contrast is simulated using a method based on the multislice technique. It appears that the cascade indu

In situ Fourier transform infrared absorption spectroscopy has been used to study the composition of particles formed and suspended in radio-frequency discharges of silane-oxygen-argon gas mixtures. The silane gas constumption was observed by infrared absorption. The stoichiometry of the produced particles depends on the silane flow rate and was compared with commercial colloidal silica. A small proportion of silane gas produces nanometric stoichiometric particles whereas a large proportion produces larger

Microstructures of three types of YBa/sub 2/Cu/sub 3/O/sub 7- delta / single crystals having strong differences in their j/sub c/ levels have been studied by means of electron microscopy. In order to find any existing relation between the microstructures and their j/sub c/ values, histograms of the frequency of twin spacings were obtained from SEM as well as TEM measurements. These histograms show that the finest and most regular twin domain texture (twin spacing 130+or-80 nm) may be correlated with the hig

Building optical matter with binding and trapping forces

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Spatially incoherent illumination as a mechanism for cross-talk suppression in wide-field optical coherence tomography

Electronic and vibrational properties of the low-dimensional perovskites Sr1-yLayNbO3.5-x

Focused electron beam induced deposition of a periodic transparent nano-optic pattern

Geant4—a simulation toolkit

Automatic Tracking of Particles in Dynamic Fluorescence Microscopy

Development of the Jungfraujoch multiwavelength lidar system for continuous observations of the aerosol optical properties in the free troposphere

Optical speedup at transparency of the gain recovery in semiconductor optical amplifiers

Light propagation and scattering in stratified media: a Green's tensor approach

Spectral and kinetic fluorescence properties of native and nonisomerizing retinal in bacteriorhodopsin

Correlation of simulated TEM images with irradiation induced damage

Silicon oxide particle formation in RF plasmas investigated by infrared absorption spectroscopy and mass spectrometry

Study of YBa/sub 2/Cu/sub 3/O/sub 7- delta / high-T/sub c/ superconductor single crystals by electron microscopy