The Experts below are selected from a list of 33285 Experts worldwide ranked by ideXlab platform
D Y Vodolazov - One of the best experts on this subject based on the ideXlab platform.
-
timing jitter in photon detection by straight superconducting nanowires effect of magnetic field and photon flux
Physical Review B, 2018Co-Authors: Mariia Sidorova, A Semenov, Heinzwilhelm Hubers, Artem Kuzmin, Steffen Doerner, Konstantin Ilin, M Siegel, Ilya Charaev, D Y VodolazovAbstract:We studied the effect of the external magnetic field and photon flux on timing jitter in photon detection by straight superconducting NbN nanowires. At two wavelengths 800 and 1560 nm, statistical distribution in the appearance time of the photon count exhibits Gaussian Shape at small times and exponential tail at large times. The characteristic exponential time is larger for photons with smaller energy and increases with external magnetic field while variations in the Gaussian part of the distribution are less pronounced. Increasing photon flux drives the nanowire from quantum detection mode to the bolometric mode that averages out fluctuations of the total number of nonequilibrium electrons created by the photon and drastically reduces jitter. The difference between Gaussian parts of distributions for these two modes provides the measure for the electron-number fluctuations. Corresponding standard deviation increases with the photon energy. We show that the two-dimensional hot-spot detection model explains qualitatively the effect of magnetic field.
-
timing jitter in photon detection by straight superconducting nanowires effect of magnetic field and photon flux
Physical Review B, 2018Co-Authors: Mariia Sidorova, A Semenov, Heinzwilhelm Hubers, Artem Kuzmin, Steffen Doerner, Konstantin Ilin, M Siegel, Ilya Charaev, D Y VodolazovAbstract:We studied the effects of the external magnetic field and photon flux on timing jitter in photon detection by straight superconducting NbN nanowires. At two wavelengths 800 and 1560 nm, statistical distribution in the appearance times of photon counts exhibits Gaussian Shape at small times and an exponential tail at large times. The characteristic exponential time is larger for photons with smaller energy and increases with external magnetic field while variations in the Gaussian part of the distribution are less pronounced. Increasing photon flux drives the nanowire from the discrete quantum detection regime to the uniform bolometric regime that averages out fluctuations of the total number of nonequilibrium electrons created by the photon and drastically reduces jitter. The difference between standard deviations of Gaussian parts of distributions for these two regimes provides the measure for the strength of electron-number fluctuations; it increases with the photon energy. We show that the two-dimensional hot-spot detection model explains qualitatively the effect of magnetic field.
James P Cline - One of the best experts on this subject based on the ideXlab platform.
-
the optics of focusing bent crystal monochromators on x ray powder diffractometers with application to lattice parameter determination and microstructure analysis
Journal of Applied Crystallography, 2019Co-Authors: Marcus H Mendenhall, David R Black, James P ClineAbstract:The use of an Incident Beam Monochromator (IBM) in an X-ray powder diffractometer modifies both the Shape of the spectrum from the X-ray source, and the relation between the apparent diffracted angle and the actual wavelength of the X-ray. For high-accuracy work, the traditional assumption of a narrow line of typically Gaussian Shape does not suffice. Both the Shape of the tails of peaks, and their width, can be described by a new model which couples the dispersion from the optic to the dispersion from the powder sample, and to its transport to a detector. This work presents such a model, and demonstrates that it produces excellent fits via the Fundamental Parameter Approach, and requires few free parameters to achieve this. Further, the parameters used are directly relatable to physical characteristics of the diffractometer optics. This agreement is critical for the evaluation of high-precision lattice parameters and crystal microstructural parameters by powder diffraction.
-
the optics of focusing bent crystal monochromators on x ray powder diffractometers with application to lattice parameter determination and microstructure analysis
Journal of Applied Crystallography, 2019Co-Authors: Marcus H Mendenhall, David R Black, James P ClineAbstract:The use of an incident-beam monochromator (IBM) in an X-ray powder diffractometer modifies both the Shape of the spectrum from the X-ray source and the relation between the apparent diffracted angle and the actual wavelength of the X-rays. For high-accuracy work, the traditional assumption of a narrow line of typically Gaussian Shape does not suffice. Both the Shape of the tails of peaks and their width can be described by a new model which couples the dispersion from the optic to the dispersion from the powder sample, and to its transport to a detector. This work presents such a model, and demonstrates that it produces excellent fits via the fundamental parameters approach and requires few free parameters to achieve this. Furthermore, the parameters used are directly relatable to physical characteristics of the diffractometer optics. This agreement is critical for the evaluation of high-precision lattice parameters and crystal microstructural parameters by powder diffraction.
Marek Osinski - One of the best experts on this subject based on the ideXlab platform.
-
blue temperature induced shift and band tail emission in ingan based light sources
Applied Physics Letters, 1997Co-Authors: Petr G Eliseev, P Perlin, Jinhyun Lee, Marek OsinskiAbstract:Electro- and photoluminescence spectra of high-brightness light-emitting AlGaN/InGaN/GaN single-quantum-well structures are studied over a broad range of temperatures and pumping levels. Blue shift of the spectral peak position was observed along with an increase of temperature and current. An involvement of band-tail states in the radiative recombination was considered, and a quantitative description of the blue temperature-induced shift was proposed assuming a Gaussian Shape of the band tail.
-
blue temperature induced shift and band tail emission in ingan based light sources
Applied Physics Letters, 1997Co-Authors: Petr G Eliseev, P Perlin, Marek OsinskiAbstract:Electro- and photoluminescence spectra of high-brightness light-emitting AlGaN/InGaN/GaN single-quantum-well structures are studied over a broad range of temperatures and pumping levels. Blue shift of the spectral peak position was observed along with an increase of temperature and current. An involvement of band-tail states in the radiative recombination was considered, and a quantitative description of the blue temperature-induced shift was proposed assuming a Gaussian Shape of the band tail.
Mariia Sidorova - One of the best experts on this subject based on the ideXlab platform.
-
timing jitter in photon detection by straight superconducting nanowires effect of magnetic field and photon flux
Physical Review B, 2018Co-Authors: Mariia Sidorova, A Semenov, Heinzwilhelm Hubers, Artem Kuzmin, Steffen Doerner, Konstantin Ilin, M Siegel, Ilya Charaev, D Y VodolazovAbstract:We studied the effect of the external magnetic field and photon flux on timing jitter in photon detection by straight superconducting NbN nanowires. At two wavelengths 800 and 1560 nm, statistical distribution in the appearance time of the photon count exhibits Gaussian Shape at small times and exponential tail at large times. The characteristic exponential time is larger for photons with smaller energy and increases with external magnetic field while variations in the Gaussian part of the distribution are less pronounced. Increasing photon flux drives the nanowire from quantum detection mode to the bolometric mode that averages out fluctuations of the total number of nonequilibrium electrons created by the photon and drastically reduces jitter. The difference between Gaussian parts of distributions for these two modes provides the measure for the electron-number fluctuations. Corresponding standard deviation increases with the photon energy. We show that the two-dimensional hot-spot detection model explains qualitatively the effect of magnetic field.
-
timing jitter in photon detection by straight superconducting nanowires effect of magnetic field and photon flux
Physical Review B, 2018Co-Authors: Mariia Sidorova, A Semenov, Heinzwilhelm Hubers, Artem Kuzmin, Steffen Doerner, Konstantin Ilin, M Siegel, Ilya Charaev, D Y VodolazovAbstract:We studied the effects of the external magnetic field and photon flux on timing jitter in photon detection by straight superconducting NbN nanowires. At two wavelengths 800 and 1560 nm, statistical distribution in the appearance times of photon counts exhibits Gaussian Shape at small times and an exponential tail at large times. The characteristic exponential time is larger for photons with smaller energy and increases with external magnetic field while variations in the Gaussian part of the distribution are less pronounced. Increasing photon flux drives the nanowire from the discrete quantum detection regime to the uniform bolometric regime that averages out fluctuations of the total number of nonequilibrium electrons created by the photon and drastically reduces jitter. The difference between standard deviations of Gaussian parts of distributions for these two regimes provides the measure for the strength of electron-number fluctuations; it increases with the photon energy. We show that the two-dimensional hot-spot detection model explains qualitatively the effect of magnetic field.
Marcus H Mendenhall - One of the best experts on this subject based on the ideXlab platform.
-
the optics of focusing bent crystal monochromators on x ray powder diffractometers with application to lattice parameter determination and microstructure analysis
Journal of Applied Crystallography, 2019Co-Authors: Marcus H Mendenhall, David R Black, James P ClineAbstract:The use of an Incident Beam Monochromator (IBM) in an X-ray powder diffractometer modifies both the Shape of the spectrum from the X-ray source, and the relation between the apparent diffracted angle and the actual wavelength of the X-ray. For high-accuracy work, the traditional assumption of a narrow line of typically Gaussian Shape does not suffice. Both the Shape of the tails of peaks, and their width, can be described by a new model which couples the dispersion from the optic to the dispersion from the powder sample, and to its transport to a detector. This work presents such a model, and demonstrates that it produces excellent fits via the Fundamental Parameter Approach, and requires few free parameters to achieve this. Further, the parameters used are directly relatable to physical characteristics of the diffractometer optics. This agreement is critical for the evaluation of high-precision lattice parameters and crystal microstructural parameters by powder diffraction.
-
the optics of focusing bent crystal monochromators on x ray powder diffractometers with application to lattice parameter determination and microstructure analysis
Journal of Applied Crystallography, 2019Co-Authors: Marcus H Mendenhall, David R Black, James P ClineAbstract:The use of an incident-beam monochromator (IBM) in an X-ray powder diffractometer modifies both the Shape of the spectrum from the X-ray source and the relation between the apparent diffracted angle and the actual wavelength of the X-rays. For high-accuracy work, the traditional assumption of a narrow line of typically Gaussian Shape does not suffice. Both the Shape of the tails of peaks and their width can be described by a new model which couples the dispersion from the optic to the dispersion from the powder sample, and to its transport to a detector. This work presents such a model, and demonstrates that it produces excellent fits via the fundamental parameters approach and requires few free parameters to achieve this. Furthermore, the parameters used are directly relatable to physical characteristics of the diffractometer optics. This agreement is critical for the evaluation of high-precision lattice parameters and crystal microstructural parameters by powder diffraction.