Search results for "time-resolved spectroscopy"
showing 10 items of 39 documents
High-Resolution Spectroscopy in Fast Atomic Beams
1977
Narrow optical resonances have been observed in fast beams of Na and Cs atoms, obtained from ion beams by charge-transfer collisions with Na, K, or Cs. Corresponding to the narrowing of the velocity distribution, occurring by acceleration, the Doppler width along the beam direction is considerably reduced [1, 2].
Luminescence properties of KNbO3 crystals
1997
Thermostimulated luminescence, X-ray-induced luminescence, photostimulated luminescence as well as the time-resolved luminescence and absorption after pulsed electron beam irradiation were studied in KNbO3 crystals at 80–400 K. A correlation between defects causing the luminescence and blue-light-induced IR absorption effects supressing the second harmonic generation efficiency in KNbO3 is discussed.
Selective excitation of up-conversion luminescence by Yb3+–Er3+ energy transfer in glass and crystalline phase of oxyfluoride glass ceramics
2010
Up-conversion luminescence of oxyfluoride glass and glass ceramics containing LaF3 crystallites doped with Yb 3+ and Er 3+ was investigated at low temperature. Excitation of Yb 3+ in the IR region revealed the fast and the slow components of Er 3+ up-conversion luminescence originating from both glass and crystalline phases. The temporal differences of the both kinds of the luminescence allowed reconstructing the excitation spectra of the up-conversion luminescence related to the glass and crystalline phases in the glass ceramics. 2010 Elsevier B.V. All rights reserved.
Time-resolved cathodoluminescence spectroscopy of YAG and YAG:Ce3+ phosphors
2019
Abstract The phosphor powders, both undoped and Ce3+ doped with different concentration Y3Al5O12 (YAG), were synthesized by the solid-state reaction method with addition of BaF2 flux. SEM and XRD characterization of the samples were performed. The spectral and luminescence decay kinetic characteristics under the electron beam irradiation with nano- and picoseconds pulse duration and the electron energies of 250 keV and 55 keV were studied, respectively. Two bands in the cathodoluminescence spectrum of YAG:Ce3+ phosphors were observed with maxima at 2.19 ± 0.05 and 2.4 eV. The intensity ratio of these two bands depends on the electron energy and the duration of the excitation pulse. Instead,…
Differentiation of natural and synthetic gem-quality diamonds by luminescence properties
2003
Abstract Laser-excited time-resolved and UV-excited static photoluminescence (PL) as well as cathodoluminescence (CL) techniques were applied to identify the origin of diamonds. Samples represented natural faced and rough diamonds from diamond market and different kimberlites as well as the most common high pressure–high temperature (HPHT) and as-grown synthetic diamonds. The time-resolved PL spectra of natural and synthetic diamonds display clear mutual differences. The static PL and CL spectra of natural diamonds revealed emission bands caused by complex nitrogen–vacancy (N–V)-aggregates whereas the bands of synthetic diamonds reflect simple N–V-aggregates and nickel-containing defects. T…
Femtosecond Raman time-resolved molecular spectroscopy
2004
Abstract The applicability of several femtosecond time resolved non-linear coherent techniques such as Raman induced polarization spectroscopy (RIPS), degenerate four-wave mixing (DFWM) and coherent anti-Stokes Raman spectroscopy (CARS) for molecular spectroscopy is presented. All methods rely on the initial coherent excitation of molecular states producing wavepackets, whose time evolution is then measured. In the case of RIPS and DFWM only pure rotational transitions are involved, whereas in CARS vibrational states can be excited. First the methodology of concentration and temperature measurements using RIPS in gas mixtures involving N2, CO2, O2, and N2O is shown. In addition some applica…
Characterization of used mineral oil condition by spectroscopic techniques
2004
Optical absorption, fluorescence, and quantitative 13C NMR spectroscopy have been used to study the degradation of mineral gearbox oil. Samples of used oil were collected from field service. Measured absorption, fluorescence, and quantitative 13C NMR spectra of used oils show characteristic changes from the spectra of a fresh oil sample. A clearly observable, approximately 20-nm blueshift of the fluorescence emission occurs during the early stages of oil use and correlates with changes in intensity of some specific 13C NMR resonance lines. These changes correlate with oil age because of the connection between the blueshift and breaking of the larger conjugated hydrocarbons of oil as a resul…
Laser-induced time-resolved luminescence in analysis of rare earth elements in apatite and calcite
2021
Laser-induced time-resolved luminescence was used to study rare earth element (REE) containing natural apatite and calcite minerals. The luminescence from 400 nm to 700 nm in the minerals was analyzed with excitation ranges 210–340 nm and 405–535 nm. As an outcome, several useful excitation wavelengths to detect one or more REE from apatite and calcite are reported. The feasibility of selected excitations in e.g. avoiding the disturbance of intense Mn2+ luminescence band, results was demonstrated with a non-gated detector. peerReviewed
From radop to laser spectroscopy and back
1985
The paper reviews some techniques in optical spectroscopy of short-lived nuclei, their results regarding nuclear moments and isotopic shift, and their relation to the work of Professor K. Sugimoto.
Laser spectroscopy of radioactive isotopes
1987
The experimental conditions for laser spectroscopy of shortlived isotopes is discussed with respect to nuclear lifetime, reaction rates and samples preparation by on-line mass-separator techniques. The method of collinear laser spectroscopy is presented with results for medium mass elements near the closed proton shell Z=50. An interpretation of magnetic moments, spectroscopic quadrupole moments and the parabolic shape of the isotope shift in this region of nuclei is given.