Effects of Yb ion concentration on the spectral properties of lead silica glasses

The spectral properties in different concentration of Yb ions (0.5-5 mol%)-doped silica glasses are explored in this paper. The glasses are prepared by traditional melting method. The absorption spectra and the fluorescent lifetime (tau(f)) are measured at room temperature and low temperature (18 K). The stimulated cross-section (sigma(emi)) and potential laser properties (beta(min), I-sat, I-min) are calculated based on the absorption spectra. The absorption cross-section (sigma(abs)) are in the range 1.08 x 10(-20) - 1.18 x 10(-20) cm(2) in different glasses, the fluorescence lifetime (tau(f)) change from 1.9 to 1.2 ms with the increase of Yb3+ concentration. The potential laser properties indicate that lead silica glass is a good host for highly Yb ion doping glass. (c) 2005 Elsevier B.V. All rights reserved.

Effect of F- ions on spectroscopic properties of Yb3+-doped zinc-tellurite glasses

this paper is retracted

Broadband near-infrared emission in Er3+-Tm3+ codoped chalcohalide glasses

The near-IR emission spectra of Er3+-Tm3+ codoped 70GeS(2)-20In(2)S(3)-10CsI chalcohalide glasses were studied with an 808 nm laser as an excitation source. A broad emission extending from 1.35 to 1.7 mu m with a FWHM of similar to 160 nm was recorded in a 0.1 mol.% Er2S3, 0.5 mol.% Tm2S3 codoped chalcohalide glass. The fluorescence decay curves of glasses were measured by monitoring the emissions of Tm3+ at 1460 nm and Er3+ at 1540 nm, and the lifetimes were obtained from the first-order exponential fit. The luminescence mechanism and the possible energy-transfer processes are discussed with respect to the energy-level diagram of Er3+ and Tm3+ ions. (C) 2008 Optical Society of America

Fluorescence properties and laser demonstrations of Nd-doped high silica glasses prepared by sintering nanoporous glass

Porous glass with high-SiO2 content was impregnated with Nd ions, and subsequently sintered at 1100 degrees C into a compact non-porous glass in air or reducing atmosphere. Sintering in a reducing atmosphere produced an intense violet-blue fluorescence at 394 nm. However, the sintering atmospheres almost did not affect the fluorescence properties in the infrared range. A good performance Nd3+-doped silica microchip laser operating at 1064 nm was demonstrated. The Nd-doped sintering glasses with high-SiO2 content are potential host materials for high power solid-state lasers and new transparent fluorescence materials. (c) 2007 Elsevier B.V. All rights reserved.

Preparation and spectroscopic properties of Yb-doped and Yb-Al-codoped high silica glasses

Yb-doped and Yb-Al-codoped high silica glasses have been prepared by sintering nanoporous glasses. The absorption, fluorescent spectra and fluorescent lifetimes have been measured and the emission cross-section and minimum pump intensities were calculated. Codoping aluminum ions enhanced the fluorescence intensity of Yb-doped high silica glass obviously. The emission cross-sections of Yb-doped and Yb-Al-codoped high silica glasses were 0.65 and 0.82 pm(2), respectively. The results show that Yb-Al-codoped high silica glass has better spectroscopic properties for a laser material. The study of high silica glass doped with ytterbium is helpful for its application in Yb laser systems, especially for high-power and high-repetition lasers. (C) 2007 Elsevier B.V. All rights reserved.

Effect of Al(PO3)(3) content on physical, chemical and optical properties of fluorophosphate glasses for 2 mu m application

The effect of Al(PO3)(3) content on physical, chemical and optical properties of fluorophosphate glasses for 2 mu m application, such as thermal stability, chemical durability, surface hardness, absorption spectra and emission spectra, is investigated. With the increment of Al(PO3)(3) content, the thermal stability characterized by the gap of T-g and T,, increases first and then decreases, and reaches the maximum level containing 5 mol% Al(PO3)(3) content. The density and chemical durability decrease monotonously with the introduction of Al(PO3)(3) content increasing, while the refractive index and surface hardness increase. Above properties of fluorophosphate glasses are also compared with fluoride glasses and phosphate glasses. The Judd-Ofelt parameters, absorption and emission cross sections are discussed based on the absorption spectra of Tm-doped glasses. The emission spectra are also measured and the 1.8 mu m fluorescence of the sample is obvious indicating that it is suitable to 2 mu m application. (c) 2008 Elsevier B.V. All rights reserved.

Effects of annealing on the color, absorption spectra, and light yield of Ce : YAlO3 single crystal grown by the temperature gradient technique

YAlO3 single crystal doped with Ce3+ at concentration 1% was grown by the temperature gradient technique. The as-grown crystal was pink. After H-2 annealing or air annealing at 1400degreesC for 20 h, the crystal was turned into colorless. We concluded there were two kinds of color centers in the as-grown crystal. One is F+ center attributed to absorption band peaking at about 530 nm, the other is O- center attributed to absorption band peaking at about 390 nm. This color centers model can be applied in explaining the experiment phenomena including the color changes, the absorption spectra changes, and the light yield changes of Ce:YAP crystals before and after annealing. (C) 2004 American Institute of Physics.

Raman spectra of undoped and uranium doped CaF2 single crystals

Raman scattering experiments for nominally pure and uranium doped CaF2 single crystals were presented. In all crystals, the Raman active T_(2g) vibration mode of CaF2 was observed, whose frequency shift and full-width at half-maximum (FWHM) broadening correspond well with defects and impurities in CaF2 lattice. Additional Raman peaks develop in nominally pure CaF2 with high etch pits density and U^(6+):CaF2 crystals. Part of additional Raman peaks in the experimental results, which are assumed due to vibration modes from F- interstitials and vacancies, are in well agreement with the theoretical predications by employing the Green-function formulation.

Upconversion luminescence from E-2 state of Cr3+ in Al2O3 crystal by infrared femtosecond laser irradiation

Visible upconversion luminescence was observed in Cr3+: Al2O3 crystal under focused femtosecond laser irradiation. The luminescence spectra show that the upconversion luminescence originates from the E-2-(4)A(2) transition of Cr3+. The dependence of the fluorescence intensity of Cr3+ on the pump power reveals that a two-photon absorption process dominates in the conversion of infrared radiation to the visible emission. It is suggested that the simultaneous absorption of two infrared photons produces the population of upper excited states, which leads to the characteristic visible emission from E-2 state of Cr3+.

Codoping Na+ to modulate the spectroscopy and photoluminescence properties of Yb3+ in CaF2 laser crystal

kinds of Yb3+- and Na+-codoped CaF2 laser crystal with different Na:Yb ratios of 0, 1.5, and 10 are grown by the temperature gradient technique. Room-temperature absorption, photoluminescence spectra, and fluorescence lifetimes belonging to the transitions between ground state F-2(7/2) and excited state F-2(5/2) of Yb3+ ions in the three crystals are measured to study the effect of Na+. Experimental results show that codoping Na+ ions in different Na:Yb ratios can modulate the spectroscopy and photoluminescence properties of Yb3+ ions in a CaF2 lattice in a large scope. (c) 2005 Optical Society of America

Study on the growth, etch morphology and spectra of Y2SiO5 crystal

Undoped Y2SiO5 single crystal was grown by the Czochralski method. The samples were optically polished after orienting and cutting. The rhombus and quadrangular dislocation etching pits, the low-angle grain boundaries and the inclusions in the samples were observed using optical microscope and scanning electron microscope. The absorption spectra were measured before and after H-2 annealing or air annealing. The absorption edge of Y2SiO5 crystal was determined to be about 202 nm. The absorption coefficient of Y2SiO5 crystal decreased after H-2 annealing and obviously increased after air annealing. (C) 2005 Elsevier B.V. All rights reserved.

Temperature dependence of the 1.03 mu m stimulated emission cross section of Cr : Yb : YAG crystal

The fluorescence emission spectra of Cr:Yb:YAG crystal are measured and the effective stimulated emission cross section of the crystal are obtained from -80 degrees C to +80 degrees C. A linear temperature dependence between -80 degrees C and +80 degrees C is reported for the 1.03 mu m peak stimulated emission cross section of Cr:Yb:YAG crystal. (c) 2004 Elsevier B.V. All rights reserved.

Temperature dependence of the 1.064-mu m stimulated emission cross-section of Cr : Nd : YAG crystal

The fluorescence emission spectra of Cr:Nd:YAG crystal are measured and the effective stimulated emission cross-section of the crystal is obtained from -80 to +80 degrees C. A linear temperature dependence between -80 and +80 degrees C is reported for the 1.064-mu m peak stimulated emission cross-section of Cr:Nd:YAG crystal. (C) 2005 Elsevier Ltd. All rights reserved.

Thermal, spectroscopic and laser properties of Yb3+Na+: CaF2 single crystals

The effects of Na+ doping level on the thermal conductivities, absorption and emission spectra, and fluorescence lifetimes of Yb3+ ,Na+ :CaF2 crystals were systematically studied. Sites structure, covalent force, and crystal field strength of Yb3+ :CaF2 crystals were markedly varied by codoping Na+ as charge compensator. The 2.0at% Yb3+ and 3.0at% Na+-codoped CaF2 crystal was demonstrated to operate in diode-pumped passively mode-locking scheme. Transform-limited 1 ps laser pulses were obtained, showing the crystal capable of producing ultra-short laser pulses. (c) 2006 Elsevier B.V. All rights reserved.