排序方式: 共有9条查询结果,搜索用时 15 毫秒
1
1.
Polarized absorption and emission spectra, and temperature dependences of the fluorescence lifetimes and intensities for the chromium-doped LiNbGeO5 laser crystal are presented. Crystal symmetry and comparison with the infrared fluorescence properties of the Cr-doped Mg2SiO4 and Y3Al5O12 laser crystals seem to identify the active center as a Cr4+ ion in a tetrahedral site. 相似文献
2.
C. Goutaudier F. S. Ermeneux M. T. Cohen-Adad R. Moncorge 《Journal of Crystal Growth》2000,210(4):693-698
High-quality and crack-free Y2O3 single crystals containing low concentrations of Tm3+, Tb3+ and Yb3+ were obtained. The crystals were grown in the form of monocrystalline fibers by using a floating zone method with laser heating (laser-heated pedestal growth). 相似文献
3.
We report on measurements of excited-state absorption spectra and absolute cross-sections in Co2+-doped KZnF3 and MgF2 at room temperature in the near-infrared domain. The data are compared with the predictions of the single-configuration co-ordinate model. 相似文献
4.
New efficient mechanisms of long-wavelength excitation of short-wavelength luminescence in a system of rare-earth impurity ions are proposed. The model studied involves a multilevel system of electronic states of a rare-earth ion interacting with the long-wavelength emission that is in resonance with one or several transitions between the excited levels. The concentration of impurity ions is assumed to be sufficiently high, so that the interionic cross-relaxation and the up-conversion play a significant role. Moreover, the model includes processes similar to photon avalanche, in which the photoinduced excitation of a single ion is converted into lower-level excitations of several ions, each of them reentering the process after photon absorption. Numerical solutions of the system of balance equations for a multilevel system are obtained with calculated and semiempirical parameters of self-quenching and up-conversion. It is shown that, in a system of Tm3+ impurity ions, short-wavelength luminescence at λ≥0.29 μm can be efficiently excited by radiation at λ?1.11 or 0.649 μm with a moderate intensity. 相似文献
5.
We report on measurements of excited-state absorption spectra and absolute cross-sections in Co2+-doped KZnF3 and MgF2 at room temperature in the near-infrared domain. The data are compared with the predictions of the single-configuration co-ordinate model. 相似文献
6.
7.
8.
9.
A. M. Tkachuk I. K. Razumova E. Yu. Perlin M. -F. Joubert R. Moncorge 《Optics and Spectroscopy》2001,90(1):78-88
Microparameters of migration and self-quenching of luminescence from the (3 P 0, 1 I 6) levels of Tm 3+ ions are calculated and the luminescence decay from the 3 H 4, 1 G 4, and 1 D 2 levels are analyzed in the concentration series of LiY1?x TmxF4(x=0.5–10 at. %) crystals upon weak selective excitation. It is shown that the luminescence decay of a thulium ion concentration higher than 0.5 at. % cannot be described by the energy transfer that takes into account only the dipole-dipole interaction. The comparison of experimental kinetic curves with theoretical curves calculated within the framework of the known energy transfer models showed that multipole-multipole interaction is responsible for the self-quenching of the thulium levels. Contributions of higher multipole interactions to the self-quenching are estimated. The decay of luminescence from the 3 H 4, 1 G 4, and 1 D 2 levels of Tm3+:YLF crystals with different concentrations of thulium ions is described analytically. 相似文献
1