Showing papers on "Erbium published in 1974"

The elastic constants of gadolinium, terbium and erbium

Abstract: The five single crystal elastic constants of gadolinium, terbium and erbium have been measured within the temperature range 4.2-300 K. Contributions to the elastic constants due to domain and spin rotation effects were reduced and in some cases eliminated altogether by applying a magnetic field of 2.5 T along the magnetic easy directions.

High energy storage lasers employing perovskites containing rare earths

Abstract: New lasers employ a halide crystal including alkali metals and rare earths with a very high concentration of the active ions that are arranged to have largest possible separation between themselves. Such laser crystals provide very high energy storage that is finally released in the form of optical radiation. The high energy storage is attributable to a relatively low gain per unit length. The halide crystal is of the perovskite type and typically includes two alkali metals, one of which, for example, sodium, has a much smaller ionic charge than the rare earths and, therefore, will be ordered on the octahedral sites of the perovskite crystal with respect to the rare earth atoms. The stoichiometry of the materials facilitates the high concentration of the rare earth active ions; and the ordering or strict sequencing of alkali and rare earth ions facilitates the large separation of the rare earth active ions which is necessary to minimize non-radiative decay via rare earth pair interaction. If other rare earths are employed other than the active ion, they can serve as diluents or energy transferring elements but are typically not ordered with respect to the active ions, even though on the octahedral sites, unless they are sufficiently different in size from the active ion. In addition, transition metal ions such as chromium can be included and will appear on the octahedral sites and serve to transfer energy to the active ion. When erbium (Er), ytterbium (Yb) or thulium (Tm) are included in suitable combinations, energy conversion of the emission from the infrared to the visible can be obtained. A typical crystal is dicesium sodium neodymium hexachloride (Cs 2 NaNdCl 6 ), in which Nd 3 + is the active ion. It is likely that the alkali metals may be replaced by other monovalent ions such as thallium (T1 + ), (Cu + ), and silver (Ag + ).

Cylindrical Erbium Oxide Radiator Structures for Thermophotovoltaic Generators.

Abstract: : Results of an experimental investigation are reported which cover the fabrication and evaluation of slip-casted and hot pressed erbium oxide cylinders and silicon carbide structures coated with erbium oxide. Suitable erbium oxide cylindrical structures will be used as radiating mantles in thermophotovoltaic converter systems. The pure erbium oxide cylindrical mantles were found to be deficient in thermal shock resistance which resulted in cracking of the mantles and extremely low thermal cycle life. The erbium oxide coated silicon carbide structures provided satisfactory thermal cycling capability up to 1500C but their spectral emission showed a large content of background radiation which manifested itself in an increased amount of undesirable interband emission. Higher optical density of the erbium oxide coating, to provide reduction of unwanted background radiation, is necessary to make these structures of practical use.

An optical filter for neodymium laser light

Abstract: An optical filter includes glass doped with erbium (Er 3 + ) ions for absorbing light at about 530 nm for protection against frequency doubled Nd-laser light; and to provide protection against Nd-laser light, ferrous (Fe 2 + ) ions are included in the glass. The glass base may be changed to broaden the absorption band, increase the absorption coefficient, or to shift the absorption band towards longer wavelengths.

Development of multiply sensitized Ho:YLF as a laser material. Final report, 15 December 1972--15 January 1974

Abstract: Abstract : TURE, THERMAL CONDUCTIVITY, DENSITY, HARDNESS, THERMAL EXPANSION, MODULUS OF ELASTICITY, OPTICAL PROPERTIES, DAMAGE, RADIATION EFFECTS*LASER MATERIALS, *LITHIUM YTTRIUM TETRAFLUORIDE, HOLMIUM IONS, HOLMIUM GLASS LASERS, THULIUM IONS, TOP SEEDED CRYSTAL GROWTH, ERBIUM IONSThe results of a twelve month program to investigate the physical, spectroscopic and laser properties of multiply sensitized Ho:YLF are presented. High two micron laser operating efficiencies at room temperature are obtained in this material as the result of absorption of pump radiation by the heavily doped sensitizing (Er(3+)-Tm(3+)-Yb(3+) ions with subsequent, rapid transfer to the active (Ho3+) species. Laser emission in the 2.06 micrometer region occurs via stimulated emission of the 5I7 - 5I8(Ho(3+) transition. A description of the technique for growth of YLF single crystals together with modifications performed during this program is included. The results of mass spectrographic analysis and chemical analysis of selected growth runs are presented. Phenomenological models of the energy transfer process have been constructed from which predictions of transfer efficiency variations with composition can be made.

Development of Multiply Sensitized Ho:YLF as a Laser Material

Abstract: : TURE, THERMAL CONDUCTIVITY, DENSITY, HARDNESS, THERMAL EXPANSION, MODULUS OF ELASTICITY, OPTICAL PROPERTIES, DAMAGE, RADIATION EFFECTS*LASER MATERIALS, *LITHIUM YTTRIUM TETRAFLUORIDE, HOLMIUM IONS, HOLMIUM GLASS LASERS, THULIUM IONS, TOP SEEDED CRYSTAL GROWTH, ERBIUM IONSThe results of a twelve month program to investigate the physical, spectroscopic and laser properties of multiply sensitized Ho:YLF are presented. High two micron laser operating efficiencies at room temperature are obtained in this material as the result of absorption of pump radiation by the heavily doped sensitizing (Er(3+)-Tm(3+)-Yb(3+) ions with subsequent, rapid transfer to the active (Ho3+) species. Laser emission in the 2.06 micrometer region occurs via stimulated emission of the 5I7 - 5I8(Ho(3+) transition. A description of the technique for growth of YLF single crystals together with modifications performed during this program is included. The results of mass spectrographic analysis and chemical analysis of selected growth runs are presented. Phenomenological models of the energy transfer process have been constructed from which predictions of transfer efficiency variations with composition can be made.