Lanthanide ions lasers

Fluorescence and Glass Lasers. Some ions absorb light of a certain frequency emitting light of lower frequency. This is known as fluorescence. Examples of ions that fluoresce in glass are Mn(TV), Pb(II), and the lanthanide ions. 

Lanthanide ion catalysts, alcoholysis with, see Transition metal ion and Ln3+ catalysts, alcoholysis Laser flash photolysis (LFP), 170, 175-178 cyclodextrins (CD), binding dynamics of guests binding to, 215-216 DNA, binding dynamics of guests binding to, 193-194... 

The rare earth (RE) ions most commonly used for applications as phosphors, lasers, and amplifiers are the so-called lanthanide ions. Lanthanide ions are formed by ionization of a nnmber of atoms located in periodic table after lanthanum from the cerium atom (atomic number 58), which has an onter electronic configuration 5s 5p 5d 4f 6s, to the ytterbium atom (atomic number 70), with an outer electronic configuration 5s 5p 4f " 6s. These atoms are nsnally incorporated in crystals as divalent or trivalent cations. In trivalent ions 5d, 6s, and some 4f electrons are removed and so (RE) + ions deal with transitions between electronic energy sublevels of the 4f" electroiuc configuration. Divalent lanthanide ions contain one more f electron (for instance, the Eu + ion has the same electronic configuration as the Gd + ion, the next element in the periodic table) but, at variance with trivalent ions, they tand use to show f d interconfigurational optical transitions. This aspect leads to quite different spectroscopic properties between divalent and trivalent ions, and so we will discuss them separately. 

Ruby was the first material for lasers but several other crystals are now employed. The crystals used need to contain an impurity with an energy level such that return to the ground state is only possible by a forbidden transition in the infrared, visible, or near ultraviolet. It must also be possible to populate this level via an allowed (or at least less forbidden) transition. Research has tended to concentrate on transition metal ions and lanthanide ions in various hosts since these ions have suitable transitions of the... 

Horrocks, W. de W. Jr. Sudnick, D. R. Lanthanide ion probes of structure in biology. Laser-induced luminescence decay constants provide a direct measure of the number of metal-coordinated water molecules. J. Am. Chem. Soc. 1979,101(2), 334-340. 

Excitation of the Eu3+ or Tb3+ ions has traditionally been indirect, by broad-band UV excitation of a conjugated organic ligand which is followed by intramolecular energy transfer to the lanthanide ion / system, followed in turn by /- / emission.614 However, more recently, following the advent of tunable dye lasers, direct excitation of an excited / level is in many cases preferable. By scanning this frequency, an excitation spectrum can be obtained whose energy values are independent of the resolution of a monochromator and not subject to spectral interferences. 

Lanthanides activated luminescent materials are widely used for solid-state lasers, luminescent lamps, flat displays, optical fiber communication systems, and other photonic devices. It is because of the unique solid-state electronic properties that enable lanthanide ions in solids to emit photons efficiently in visible and near IR region. Due to the pioneer work by Dieke, Judd, Wyboume, and others in theoretical and experimental studies of the... 

Initially, interest for NIR emission of lanthanide ions stemmed from the development of optical libers, lasers and amplifiers for telecommunication (Kido and Okamoto, 2002 Kuriki et al., 2002) and there are a wealth of theoretical and technical papers published in this area. Up-conversion processes have also been the subject of intense investigations (Auzel, 2004). These two areas of research and development mostly deal with purely inorganic compounds or, more recently, with luminescent polymers they will not be covered in this chapter, with the exception of the latter, which will be partly described. 

Because of the optical quality and chemical stability of crystals, the low probability of non radiative processes and the wide transmission range, fluorides are the most appropriate materials for solid state lasers with specific wavelengths. Thus the 4f - 4f line emissions of lanthanide ions have been used in order to obtain infrared laser radiation up to 4.34 fxm and blue or green radiation by up-conversion pumping. Tunable laser operation in the ultraviolet has been demonstrated using the broad 5d 4f emission of Ce3+. Tunable lasers in the UV or IR ranges have also been experimented using Ag+, Pb+, 3d ions. 

Although the conductivity of the trivalent-ion / ""-aluminas is too low for solid electrolyte applications (e g. batteries, sensors), they have potential use in optics, phosphors, and lasers because they can serve as single crystal or powder hosts for the optically active lanthanide ions. For example, Eu +-/3""-alumina emits red luminescence when excited by UV rays. A Nd +-/3""-alumina single crystal shows luminescent... 

Figure 1.6 The energy level diagram for trivalent lanthanide ions [7]. (With kind permission from Springer Science+Business Media Lasers and Excited States of Rare Earths, 1977, p. 93, R. Reisfeld, and C.K. Jorgensen, figure 2, Springer-Verlag, Berlin.)...

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