scholarly journals Terahertz Spectroscopy of Novel Superconductors

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Stefano Lupi
Keyword(s):  
Synchrotron Radiation ◽  
Fermi Energy ◽  
Terahertz Spectroscopy ◽  
Signal To Noise Ratio ◽  
Spectroscopic Technique ◽  
Signal To Noise ◽  
Boron Doped Diamond ◽  
Boron Doped ◽  
Reflectivity Spectra ◽  
Michelson Interferometry

Through the coupling of Synchrotron Radiation and Michelson interferometry, one may obtain in the terahertz (THz) range transmittance and reflectivity spectra with a signal-to-noise ratio (S/N) up to 103. In this paper we review the application of this spectroscopic technique to novel superconductors with an increasing degree of complexity: the single-gap boron-doped diamond; the isotropic multiband V3Si, where superconductivity opens two gaps at the Fermi energy; the CaAlSi superconductor, isostructural to MgB2, with a single gap in the hexagonal ab plane and two gaps along the orthogonalcaxis.

Terahertz Spectroscopy of Superconductors

2010 ◽  
Vol 75 ◽  
pp. 147-154
Author(s):  
Stefano Lupi ◽  
Leonetta Baldassarre ◽  
Paolo Calvani ◽  
Paolo Dore ◽  
Chiara Mirri ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Superconducting State ◽  
Fermi Energy ◽  
Isotropic Material ◽  
Terahertz Spectroscopy ◽  
Signal To Noise Ratio ◽  
Michelson Interferometer ◽  
Signal To Noise ◽  
Boron Doped Diamond ◽  
Boron Doped

We show how synchrotron radiation (SR) in the terahertz (THz) region provides the possibility to measure the properties of conventional and exotic superconductors in their superconducting state. Indeed, through the coupling of SR and a conventional Michelson interferometer, one can obtain in the THz range a signal-to-noise ratio up to 103. We review the application of this technique to superconductors with a different degree of complexity: the single-gap boron-doped diamond BCS isotropic material; CaAlSi, a superconductor isostructural to MgB2 with a slight anisotropy between the gap in the hexagonal planes and that along the orthogonal c axis; and isotropic V3Si, where superconductivity opens two gaps at the Fermi energy.

In situ studies of metal–semiconductor interactions with synchrotron radiation

1998 ◽  
Vol 5 (3) ◽  
pp. 1050-1051
Author(s):  
D. E. Sayers ◽  
P. T. Goeller ◽  
B. I. Boyanov ◽  
R. J. Nemanich
Keyword(s):  
Synchrotron Radiation ◽  
Silicon Germanium ◽  
Signal To Noise Ratio ◽  
Thick Films ◽  
Strained Silicon ◽  
Reaction Products ◽  
Signal To Noise ◽  
In Situ Studies ◽  
And Performance

The capabilities and performance of a UHV system for in situ studies of metal–semiconductor interactions are described. The UHV system consists of interconnected deposition and analysis chambers, each of which is capable of maintaining a base pressure of approximately 1 × 10−10 torr. The deposited materials and their reaction products can be studied in situ with RHEED, XAFS, AES, XPS, UPS and ARUPS. Results from a study of the reaction of 0.7- and 1.7-monolayer-thick films of cobalt with strained silicon–germanium alloys are presented. The signal-to-noise ratio obtained in these experiments indicates that the apparatus is capable of supporting in situ EXAFS studies of ∼0.1-monolayer-thick films.

scholarly journals Terahertz spectroscopy in biomedical field: a review on signal-to-noise ratio improvement

PhotoniX ◽  
2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Yan Peng ◽  
Chenjun Shi ◽  
Yiming Zhu ◽  
Min Gu ◽  
Songlin Zhuang
Keyword(s):  
Terahertz Spectroscopy ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Biomedical Field ◽  
Noise Ratio

Signal-to-noise ratio evaluation in dual-energy radiography with synchrotron radiation

2002 ◽  
Vol 47 (22) ◽  
pp. 4093-4105 ◽  
Author(s):  
S Fabbri ◽  
A Taibi ◽  
R Longo ◽  
M Marziani ◽  
A Olivo ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Signal To Noise Ratio ◽  
Dual Energy ◽  
Signal To Noise ◽  
Noise Ratio

Photoluminescence Properties of CVD Diamond Excited by Ultra-Violet Synchrotron Radiation

1996 ◽  
Vol 423 ◽  
Author(s):  
Jaihyung Won ◽  
Akimitsu Hatta ◽  
Toshimichi Ito ◽  
Takatomo Sasaki ◽  
Akio Hiraki
Keyword(s):  
Synchrotron Radiation ◽  
Defect Formation ◽  
Chemical Vapor ◽  
Ultra Violet ◽  
Cvd Diamond ◽  
Photoluminescence Properties ◽  
Boron Doped Diamond ◽  
Near Surface ◽  
Microwave Assisted ◽  
Boron Doped

AbstractPhotoluminescence (PL) properties of microwave-assisted chemical-vapor- deposition (CVD) diamond have been studied using ultraviolet synchrotron radiation. The defect-related 5RL PL feature, which was not detected in cathodoluminescence (CL), was observed for both undoped and boron-doped (200ppm) CVD diamond. The defect formation in the thin near- surface layer is discussed in relation to dependence of PL spectra on incident photon energy. In the case of boron-doped diamond, the boron-related peak was detected at 2.3eV while the band-A feature was not observed at 2.9eV. PL excitation (PLE) spectra associated with these emissions are also discussed in relation to absorption coefficients at energies above the band gap.

Synchrotron radiation X-ray analysis of boron-doped diamond films grown by hot-filament assisted chemical vapor deposition

2002 ◽  
Vol 11 (2) ◽  
pp. 153-159 ◽  
Author(s):  
Leide L.G Silva ◽  
Margareth K Franco ◽  
Fabiano Yokaichiya ◽  
Neidenei G Ferreira ◽  
Evaldo J Corat
Keyword(s):  
Chemical Vapor Deposition ◽  
Synchrotron Radiation ◽  
Vapor Deposition ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Boron Doped Diamond ◽  
X Ray ◽  
Boron Doped ◽  
Hot Filament

Fourier Transform Infrared Spectrochemical Imaging: Review of Design and Applications with a Focal Plane Array and Multiple Beam Synchrotron Radiation Source

2012 ◽  
Vol 66 (5) ◽  
pp. 475-491 ◽  
Author(s):  
Carol J. Hirschmugl ◽  
Kathleen M. Gough
Keyword(s):  
Synchrotron Radiation ◽  
Focal Plane ◽  
Signal To Noise Ratio ◽  
Focal Plane Array ◽  
Quality Data ◽  
Small Scale ◽  
Signal To Noise ◽  
High Quality ◽  
Mid Infrared ◽  
Noise Ratio

The beamline design, microscope specifications, and initial results from the new mid-infrared beamline (IRENI) are reviewed. Synchrotron-based spectrochemical imaging, as recently implemented at the Synchrotron Radiation Center in Stoughton, Wisconsin, demonstrates the new capability to achieve diffraction limited chemical imaging across the entire mid-infrared region, simultaneously, with high signal-to-noise ratio. IRENI extracts a large swath of radiation (320 hor. × 25 vert. mrads 2 ) to homogeneously illuminate a commercial infrared (IR) microscope equipped with an IR focal plane array (FPA) detector. Wide-field images are collected, in contrast to single-pixel imaging from the confocal geometry with raster scanning, commonly used at most synchrotron beamlines. IRENI rapidly generates high quality, high spatial resolution data. The relevant advantages (spatial oversampling, speed, sensitivity, and signal-to-noise ratio) are discussed in detail and demonstrated with examples from a variety of disciplines, including formalin-fixed and flash-frozen tissue samples, live cells, fixed cells, paint cross-sections, polymer fibers, and novel nanomaterials. The impact of Mie scattering corrections on this high quality data is shown, and first results with a grazing angle objective are presented, along with future enhancements and plans for implementation of similar, small-scale instruments.

Determination of the Best Emulsion for the Microscopy of Crystals

1981 ◽  
Vol 39 ◽  
pp. 32-33
Author(s):  
David A. Grano ◽  
Kenneth H. Downing
Keyword(s):  
Spatial Frequency ◽  
Information Transfer ◽  
Signal To Noise Ratio ◽  
Experimental Situation ◽  
Photographic Emulsion ◽  
Modulation Transfer ◽  
Signal To Noise ◽  
Frequency Space ◽  
Noise Ratio

The retrieval of high-resolution information from images of biological crystals depends, in part, on the use of the correct photographic emulsion. We have been investigating the information transfer properties of twelve emulsions with a view toward 1) characterizing the emulsions by a few, measurable quantities, and 2) identifying the “best” emulsion of those we have studied for use in any given experimental situation. Because our interests lie in the examination of crystalline specimens, we've chosen to evaluate an emulsion's signal-to-noise ratio (SNR) as a function of spatial frequency and use this as our critereon for determining the best emulsion.The signal-to-noise ratio in frequency space depends on several factors. First, the signal depends on the speed of the emulsion and its modulation transfer function (MTF). By procedures outlined in, MTF's have been found for all the emulsions tested and can be fit by an analytic expression 1/(1+(S/S0)2). Figure 1 shows the experimental data and fitted curve for an emulsion with a better than average MTF. A single parameter, the spatial frequency at which the transfer falls to 50% (S0), characterizes this curve.

Experiments in Bright-Field Imaging with Hollow-Cone Illumination

1981 ◽  
Vol 39 ◽  
pp. 226-227
Author(s):  
W. Kunath ◽  
K. Weiss ◽  
E. Zeitler
Keyword(s):  
Signal To Noise Ratio ◽  
Carbon Support ◽  
Electronic System ◽  
Optic Axis ◽  
Hollow Cone ◽  
Signal To Noise ◽  
Bright Field ◽  
Noise Ratio ◽  
Single Field ◽  
Field Imaging

Bright-field images taken with axial illumination show spurious high contrast patterns which obscure details smaller than 15 ° Hollow-cone illumination (HCI), however, reduces this disturbing granulation by statistical superposition and thus improves the signal-to-noise ratio. In this presentation we report on experiments aimed at selecting the proper amount of tilt and defocus for improvement of the signal-to-noise ratio by means of direct observation of the electron images on a TV monitor.Hollow-cone illumination is implemented in our microscope (single field condenser objective, Cs = .5 mm) by an electronic system which rotates the tilted beam about the optic axis. At low rates of revolution (one turn per second or so) a circular motion of the usual granulation in the image of a carbon support film can be observed on the TV monitor. The size of the granular structures and the radius of their orbits depend on both the conical tilt and defocus.

Correlation averaging of two-dimensional crystals: basic strategy and refinements

1986 ◽  
Vol 44 ◽  
pp. 136-139
Author(s):  
W. Baumeister ◽  
R. Rachel ◽  
R. Guckenberger ◽  
R. Hegerl
Keyword(s):  
Low Dose ◽  
Signal To Noise Ratio ◽  
Real Space ◽  
Fourier Domain ◽  
Two Dimensional ◽  
Signal To Noise ◽  
Unit Cells ◽  
Lateral Displacements ◽  
Established Technique ◽  
Crystalline Array

IntroductionCorrelation averaging (CAV) is meanwhile an established technique in image processing of two-dimensional crystals /1,2/. The basic idea is to detect the real positions of unit cells in a crystalline array by means of correlation functions and to average them by real space superposition of the aligned motifs. The signal-to-noise ratio improves in proportion to the number of motifs included in the average. Unlike filtering in the Fourier domain, CAV corrects for lateral displacements of the unit cells; thus it avoids the loss of resolution entailed by these distortions in the conventional approach. Here we report on some variants of the method, aimed at retrieving a maximum of information from images with very low signal-to-noise ratios (low dose microscopy of unstained or lightly stained specimens) while keeping the procedure economical.

Sign in / Sign up

Export Citation Format

Share Document