Topic
Absorption (logic)
About: Absorption (logic) is a research topic. Over the lifetime, 5733 publications have been published within this topic receiving 236302 citations.
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TL;DR: The real and imaginary parts of the dielectric constant of SrTi${\mathrm{O}}_{3}$ have been obtained for the region 2.5 to 3000 from an analysis of the reflectivity.
Abstract: The real and imaginary parts of the dielectric constant of SrTi${\mathrm{O}}_{3}$ have been obtained for the region 2.5 to 3000 ${\mathrm{cm}}^{\ensuremath{-}1}$ from an analysis of the reflectivity. The imaginary part exhibits a very strong peak at 100 ${\mathrm{cm}}^{\ensuremath{-}1}$ at room temperature which shifts to 40 ${\mathrm{cm}}^{\ensuremath{-}1}$ at 93\ifmmode^\circ\else\textdegree\fi{}K. This mode is of sufficient strength to account for more than 90% of the low-frequency dielectric constant. The accompanying dispersion of the real part of the dielectric constant is of resonant form. The connection of this mode with Cochran's theory of ferroelectricity is discussed.
175 citations
TL;DR: In this article, the optical and paramagnetic spectra of divalent cobalt in MgO single crystals are reported and the effect of charge transfer is (1) to shield the nuclear charge and (2) to normalize the wave functions.
Abstract: The optical and paramagnetic resonance spectra of divalent cobalt in MgO single crystals are reported. The optical spectrum consists of stronger lines which correspond to transitions between Stark levels of the same multiplicities and weak intercombination lines. If the Slater integrals are taken as free parameters then in the intermediate coupling scheme good agreement is obtained between the observed and calculated spectrum with $Dq=960$ ${\mathrm{cm}}^{\ensuremath{-}1}$. The Slater integrals are reduced by about 8-10% from those of the free ion. The paramagnetic resonance spectrum shows one electronic isotropic transition consisting of eight hyperfine lines at $g={4.278}_{5}\ifmmode\pm\else\textpm\fi{}0.001$ and $A=({97.7}_{9}\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ ${\mathrm{cm}}^{\ensuremath{-}1}$. The interpretation of these results shows that the orbital reduction factor $k=0.89\ensuremath{-}0.85$. Both the optical and paramagnetic results indicate covalent bonding. The effect of charge transfer is (1) to shield the nuclear charge and (2) to normalize the wave functions. Both these effects results in smaller Coulomb energy, hyperfine structure, and spin-orbit coupling constant.No distortions of octahedral symmetry have been found to within ${10}^{\ensuremath{-}3}$ ${\mathrm{cm}}^{\ensuremath{-}1}$. The static Jahn-Teller effect which predicts such a distortion is, therefore, very small.
175 citations
TL;DR: Fluorescein-doped boric acid glass is a material characterized by an extremely low saturation intensity of —15 mWcm and a nonlinear susceptibility g"' as large as —1 esu.
Abstract: Fluorescein-doped boric acid glass is a material characterized by an extremely low saturation intensity of \ensuremath{\sim}15 mW${\mathrm{?}}^{\mathrm{\ensuremath{-}}2}$ and a nonlinear susceptibility ${\ensuremath{\chi}}^{(3)}$ as large as \ensuremath{\sim}1 esu. The saturated absorption of this material is shown both theoretically and experimentally to depend on the state of polarization of the saturating beam, even though the unsaturated absorption is polarization insensitive. Phase-conjugate reflectivities as large as 0.6% have been obtained through use of degenerate four-wave mixing in this material. These measured reflectivities are in good agreement with the predictions of a theory that includes the effects of excited-state absorption and grating washout. In addition, two-beam coupling due to the nonlinearity of saturable absorption has been demonstrated in this material. The magnitude of the coupling is maximized by inducing a frequency shift between the two beams of \ensuremath{\sim}0.1 Hz.
175 citations
TL;DR: In this article, the atomic recoil from the absorption of up to 60 photons was measured using an atom interferometer, with a precision of 10^{10}^{\mathrm{\ensuremath{-}}7}$ in 2 h of integration time.
Abstract: The atomic recoil from the absorption of up to 60 photons is measured using an atom interferometer. We determine \ensuremath{\Elzxh}/${\mathit{m}}_{\mathrm{Cs}}$ with a precision of ${10}^{\mathrm{\ensuremath{-}}7}$ in 2 h of integration time.
174 citations
TL;DR: In this paper, the authors show that photo-cells made from CdS, CdSe, and CdTe are extremely sensitive in the whole region from the infra-red down to the ultraviolet, x-rays, and gamma-rays and for corpuscular rays, alpha- and beta-rays.
Abstract: Synthetic single crystals of CdS, CdSe, and CdTe have been produced by the reaction of cadmium vapor with ${\mathrm{H}}_{2}$S, ${\mathrm{H}}_{2}$Se, and ${\mathrm{H}}_{2}$Te, respectively. These "incomplete phosphors" show no phosphorescence but strongly developed photo-conductivity. Photo-cells made from these crystals are extremely sensitive in the whole region from the infra-red down to the ultraviolet, x-rays, and gamma-rays and for corpuscular rays, alpha- and beta-rays. Two different mechanisms of photo-conductivity occur. The normal photo-conductivity in the region of strong absorption from the blue to the ultraviolet, and the selective photo-conductivity in the region of weak absorption in the visible, x-rays, and corpuscular-rays region. The phenomena observed are in general accordance with the zonal theory of phosphorescence.
173 citations