Results 221 to 230 of about 250,736 (266)
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Two-photon and two-photon-assisted slow light
Optics Letters, 2011We show that light pulses propagating in two-photon absorbing systems may present time delays like slow light produced via coherent population oscillations in one-photon interactions. Two regimes are numerically studied for a simplified two-level system: (a) a light pulse at frequency ω/2 undergoes two-photon absorption (TPA) and is delayed by the ...
E Sánchez, Bautista +2 more
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Physical Review D, 1992
The production of two photons by electrons and positrons in very-high-energy linear colliders is considered. The phase of the amplitude is discussed in detail and the dominant radiation zone is determined. The arguments that the multiphoton radiation is an incoherent process are confirmed.
, Jedrzejczak, , Kurek
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The production of two photons by electrons and positrons in very-high-energy linear colliders is considered. The phase of the amplitude is discussed in detail and the dominant radiation zone is determined. The arguments that the multiphoton radiation is an incoherent process are confirmed.
, Jedrzejczak, , Kurek
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Physical Review A, 1987
We present a calculation of the cross sections for two-photon bremsstrahlung in a Coulomb potential. The calculation was done in second-order nonrelativistic perturbation theory and in the dipole approximation. The potential was taken into account exactly by using the Coulomb Green's function.
, Véniard, , Gavrila, , Maquet
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We present a calculation of the cross sections for two-photon bremsstrahlung in a Coulomb potential. The calculation was done in second-order nonrelativistic perturbation theory and in the dipole approximation. The potential was taken into account exactly by using the Coulomb Green's function.
, Véniard, , Gavrila, , Maquet
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Two-photon transitions with cascades: Two-photon transition rates and two-photon level widths
Physical Review A, 2014An ambiguity of the separation of cascades from ``pure'' two-photon decay is confirmed with accurate numerical calculations in a gauge-invariant way. A direct evaluation of the two-photon decay width of excited states in H-like ions via the imaginary part of two-loop self-energy is presented.
T. Zalialiutdinov +3 more
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Two-Photon Selective Reflection
EQEC 96 1996 European Quantum Electronic Conference EQEC-96, 1996The conditions of observation of direct two-photon-induced dispersion in three-level reflection spectroscopy at a vapor-dielectric interface are discussed. One shows how pump frequency modulation allows one to discriminate the two-photon singular contribution associated with atoms moving quasiparallel to the dielectric interface, and therefore single ...
, Gorris-Neveux +5 more
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Nuclear Physics B - Proceedings Supplements, 2003
A review of the recent experimental results on two photon physics at LEP is presented. The total cross section for γγ → hadrons is measured for two-photon centre-of-mass energies up to 160 GeV. The QCD predictions are tested with measurements of the total hadronic cross section for virtual γ * γ * collisions, with heavy flavour ( c c ¯
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A review of the recent experimental results on two photon physics at LEP is presented. The total cross section for γγ → hadrons is measured for two-photon centre-of-mass energies up to 160 GeV. The QCD predictions are tested with measurements of the total hadronic cross section for virtual γ * γ * collisions, with heavy flavour ( c c ¯
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2014
Two-photon (TP) laser scanning microscopy has become an important tool for noninvasive biomedical imaging. TP fluorophore excitation using (near) infrared wavelengths show enhanced tissue penetration and reduced photodamage of biological specimen. This modality allows noninvasive three-dimensional deep-tissue imaging with submicron resolution, which ...
Wu, Zhuojun, van Zandvoort, Marc
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Two-photon (TP) laser scanning microscopy has become an important tool for noninvasive biomedical imaging. TP fluorophore excitation using (near) infrared wavelengths show enhanced tissue penetration and reduced photodamage of biological specimen. This modality allows noninvasive three-dimensional deep-tissue imaging with submicron resolution, which ...
Wu, Zhuojun, van Zandvoort, Marc
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Two-Photon Photodynamic Therapy
Journal of Clinical Laser Medicine & Surgery, 1997We demonstrate the use of infrared excitation in conjunction with an efficient two-photon absorbing dye and a photosensitizer in photodynamic therapy.An efficient two-photon absorbing dye is excited by short infrared (800 nm) laser pulses, which transfer its energy to the photosensitizer and the photosensitizer, in turn, generates the singlet oxygen.A ...
J D, Bhawalkar +3 more
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2004
Publisher Summary This chapter describes a new cytometry technique based on the combination of Two-photon microscopy (TPM) and high-speed imaging techniques. TPM is a high-resolution fluorescence microscopy technique that provides 3D images of cells and tissues. It is well suited for imaging tissues. By incorporating high-speed image capabilities, it
Timothy, Ragan +3 more
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Publisher Summary This chapter describes a new cytometry technique based on the combination of Two-photon microscopy (TPM) and high-speed imaging techniques. TPM is a high-resolution fluorescence microscopy technique that provides 3D images of cells and tissues. It is well suited for imaging tissues. By incorporating high-speed image capabilities, it
Timothy, Ragan +3 more
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Two-Photon Fluorescence Imaging
2021Two-photon fluorescence imaging is a powerful tool for observing the dynamics of cells in vivo in intact tissue and is well suitable for imaging neuronal activity for neuroscience research. Due to the nonlinear two-photon absorption, the optical sectioning ability is inherent, resulting in two-photon images with high signal contrast and signal-to-noise
Fan, Feng +3 more
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