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Lupei V.,National Institute for Laser, Plasma and Radiation Physics | Lupei A.,National Institute for Laser, Plasma and Radiation Physics | Gheorghe C.,National Institute for Laser, Plasma and Radiation Physics | Ikesue A.,World Laboratory Co.
Optical Materials Express | Year: 2016

High resolution spectroscopy brings new data on the spectroscopic and energy transfer properties of the transparent (Cr,Nd):YAG ceramics. The role of joint superexchange and electric dipole interactions in the Cr-to-Nd energy transfer is evidenced and the calculated emission quantum efficiency is essentially determined by the Nd concentration, 52% for 1 at.%Nd and 77% for 2 at.%Nd. The implication of Cr and Nd concentrations on the laser emission and heat generation under broad-band pumping is discussed. © 2016 Optical Society of America. Source


Lupei A.,National Institute for Laser, Plasma and Radiation Physics | Lupei V.,National Institute for Laser, Plasma and Radiation Physics | Gheorghe C.,National Institute for Laser, Plasma and Radiation Physics | Hau S.,National Institute for Laser, Plasma and Radiation Physics | Ikesue A.,World Laboratory Co.
Optical Materials | Year: 2014

New aspects on the Ce3+ in YAG transparent ceramics, obtained from absorption and emission spectra in the 10-300 K range, under different visible excitation wavelengths, along with emission decays are presented. The spectra and lifetime of regular (Formula presented.) center are similar to those reported for single crystals. In the attempt to reveal perturbed Ce3+ centers by defects, the 5d → 4f emission spectra under pulsed 532 nm (5 ns) excitation (below the Ce3+ absorption band) were recorded. The spectra and decays (at different wavelengths) are function on temperature, revealing at least three types of Ce3+ new emitting centers. The low temperature spectra, different from those of (Formula presented.) center, are dominated by a set of strongly perturbed centers with very short lifetimes. At least two other types of perturbed centers were separated by using wavelength and temperature dependences of decays. The spectral characteristics of these perturbed Ce3+ centers by lattice defects are analyzed in terms of the effects of the structural changes induced by Ce3+ doping on the interaction with defects, by using recent reported results. © 2014 Elsevier B.V. All rights reserved. Source


Lupei A.,Romanian National Institute for Lasers, Plasma and Radiation Physics | Lupei V.,Romanian National Institute for Lasers, Plasma and Radiation Physics | Gheorghe C.,Romanian National Institute for Lasers, Plasma and Radiation Physics | Ikesue A.,World Laboratory Co.
Romanian Reports in Physics | Year: 2011

An analysis of the high resolution optical spectra (at 10 or 300 K) of Sm3+ in YAG transparent ceramics is presented. The peculiarities of the spectra in ceramics are outlined. Accurate data for the application of Sm3+: YAG ceramic to suppress parasitic oscillations in high power Nd: YAG ceramic composite lasers are obtained. Source


Lupei A.,Romanian National Institute for Lasers, Plasma and Radiation Physics | Lupei V.,Romanian National Institute for Lasers, Plasma and Radiation Physics | Ikesue A.,World Laboratory Co. | Gheorghe C.,Romanian National Institute for Lasers, Plasma and Radiation Physics
Journal of the Optical Society of America B: Optical Physics | Year: 2010

The Nd3+→Yb3+ energy transfer spectral characteristics in (Nd,Yb):Y2O3 ceramics and the relevant spectral and emission decay data on single-doped (especially temperature effects) and codoped samples are presented. The transfer efficiencies depend strongly on Yb3+ content, attaining ∼98% for Nd1 at.%-Yb5 at.% at 300 K. The resonant Nd3+→Yb3+ energy transfer ( 4F3/2(Nd), 2F7/2(Yb))→( 4I9/2(Nd), 2F5/2(Yb)), involving Nd3+ in C2 sites and Yb3+ in C2 and C3i sites, is dominated by a dipole-dipole interaction with a microparameter CDA,Nd-Yb≈1×10?38 cm6 s?1 at 300 K. The possibility of using this system for Nd-sensitized Yb3+ laser emission from room-to-cryogenic temperatures is discussed. © 2010 Optical Society of America. Source


Lupei A.,Romanian National Institute for Lasers, Plasma and Radiation Physics | Lupei V.,Romanian National Institute for Lasers, Plasma and Radiation Physics | Ikesue A.,World Laboratory Co. | Gheorghe C.,Romanian National Institute for Lasers, Plasma and Radiation Physics | Hau S.,Romanian National Institute for Lasers, Plasma and Radiation Physics
Optical Materials | Year: 2010

In the attempt to obtain new efficient laser systems, the Nd → Yb energy transfer characteristics in Y2O3 transparent ceramics were investigated. The spectral characteristics that assure the efficient resonant Nd3+ → Yb3+ energy transfer are presented, especially the overlap integral of the Nd3+ 4F3/2 → 4I9/2 emission with the Yb3+ 2F7/2 → 2F5/2 absorption in (Nd, Yb):Y2O3. The static spectral data reveal that the Nd3+ → Yb3+ energy transfer shows: a strong dependence on Yb3+ content (less on Nd3+), a small variation with temperature and the implication of both Yb3+ sites in transfer, though only Nd3+ in C2 are active. From the analysis of Nd3+ 4F3/2 emission decays in double doped samples it is concluded that the Nd → Yb transfer for Nd ∼1 at.% is of direct type, through the dipole-dipole interaction with global energy transfer microparameter ∼CDA,Nd-Yb ≈ 1 × 10-38 cm6 s-1 and transfer efficiencies up to 98% for rather low (∼5 at.%) Yb3+ content. © 2010 Elsevier B.V. All rights reserved. Source

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