Spectroscopic properties of Nd3+ in orthorhombic δ-BiB3O6 crystal

Absorption spectra of the Nd3+ ions in an orthorhombic δ-BiB3O6 single crystal were measured in the spectral range 11,000-20,500 cm−1. The f-f transition intensities were analyzed in terms of the Judd-Ofelt theory, and the following parameters of the theory were obtained: Ω2 = 6.35 × 10−20 cm2, Ω4 = 4.86 × 10−20 cm2, and Ω6 = 11.233 × 10−20 cm2. The strengths, spontaneous emission probabilities, branching ratios, spectroscopic quality factor and excited state radiative lifetime were calculated for laser transitions from the 4F3/2 state to 4IJ manifold. Spectroscopicproperties of Nd3+:δ-BiB3O6crystal favor lasing at 1.3 μm, where this crystal possesses near non-critical phase matching for second harmonic generation

Spectroscopic properties of Nd3+ in orthorhombic δ-BiB3O6 crystal

International audienceAbsorption spectra of the Nd3+ ions in an orthorhombic δ-BiB3O6 single crystal were measured in the spectral range 11,000-20,500 cm−1. The f-f transition intensities were analyzed in terms of the Judd-Ofelt theory, and the following parameters of the theory were obtained: Ω2 = 6.35 × 10−20 cm2, Ω4 = 4.86 × 10−20 cm2, and Ω6 = 11.233 × 10−20 cm2. The strengths, spontaneous emission probabilities, branching ratios, spectroscopic quality factor and excited state radiative lifetime were calculated for laser transitions from the 4F3/2 state to 4IJ manifold. Spectroscopicproperties of Nd3+:δ-BiB3O6crystal favor lasing at 1.3 μm, where this crystal possesses near non-critical phase matching for second harmonic generation

Lasing properties of new Yb-doped borate compounds with varying gadolinium and yttrium concentration

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Spectroscopic properties of Nd3+ in orthorhombic δ-BiB3O6 crystal

Absorption spectra of the Nd3+ ions in an orthorhombic δ-BiB3O6 single crystal were measured in the spectral range 11,000-20,500 cm−1. The f-f transition intensities were analyzed in terms of the Judd-Ofelt theory, and the following parameters of the theory were obtained: Ω2 = 6.35 × 10−20 cm2, Ω4 = 4.86 × 10−20 cm2, and Ω6 = 11.233 × 10−20 cm2. The strengths, spontaneous emission probabilities, branching ratios, spectroscopic quality factor and excited state radiative lifetime were calculated for laser transitions from the 4F3/2 state to 4IJ manifold. Spectroscopicproperties of Nd3+:δ-BiB3O6crystal favor lasing at 1.3 μm, where this crystal possesses near non-critical phase matching for second harmonic generation

Luminescence study of defects in silica glasses under near-UV excitation

In this paper, we report the results of photo-luminescence experiments on high purity silica glass. Two different types of defects located on optical pieces are investigated: indented sites and laser damage craters. Visible luminescence excited at the wavelength of 325 nm (3.81 eV) is observed using confocal microscopy. Each type of defect produces qualitatively different luminescence spectra. In the case of indented sites, the well known Oxygen Deficient Center (ODC) band peaking at 2.75 eV is clearly observed, while for laser damage areas, another classical luminescent object is found: the Non Bridging Oxygen Hole Center (NBOHC) which peaks at 1.9 eV. On both types of defects, the luminescence spectra yield a strong peak around 2.2 eV but its interpretation is still controversory

Sol-gel technique for the generation of europium-doped mesoporous and dense thin films: A luminescent study

In this paper, a series of europium-activated titania mesoporous and dense thin films were prepared by sol-gel process. Structural characterizations show that high europium ion loadings can be incorporated into titanium dioxide walls with out destroy in the mesoporous arrangement. However, high europium content locks the titanium dioxide crystallization process. Upon 10% europiumions loading, mesoporous thin films are mainlyamorphous, whereas dense ones are still partially crystallized. Eu3+ ion luminescence has been investigated by exciting through the semiconductor host lattice. Emission features reveal that europiumions adopt similar environments (nano crystalline and glassy-likeones) in both dense and mesoporous thin films. Fluctuations of europium emission under continuous UV excitation have been observed. One observes that the effect strongly depends on the thin films'crystalline character which is strongly related with the texturation and existence at the mesoscopic length scale

Evidence of a green luminescence band related to surface flaws in high purity silica glass

Using luminescence confocal microscopy under 325 nm laser excitation, we explore the populations of defects existing in or at the vicinity of macroscopic surface flaws in fused silica. We report our luminescence results on two types of surface flaws: laser damage and indentation on fused silica polished surfaces. Luminescence cartographies are made to show the spatial distribution of each kind of defect. Three bands, centered at 1.89 eV, 2.75 eV and 2.25 eV are evidenced on laser damage and indentations. The band centered at 2.25 eV was not previously reported in photo luminescence experiments on indentations and pristine silica, for excitation wavelengths of 325 nm or larger. The luminescent objects, expected to be trapped in sub-surface micro-cracks, are possibly involved in the first step of the laser damage mechanism when fused silica is enlightened at 351 nm laser in nanosecond regime

Defect chemistry to trigger zirconia densification at low temperatures by Spark Plasma Sintering

In-depth control of reactivity and defects chemistry is shown to be mandatory to reach high density YSZ ceramics at sintering temperatures lower than 900°C. The combination of Cold Sintering Process (CSP) and Spark Plasma Sintering (SPS) has highlighted the role of transient chemistry on the densification of this material. More, optimised conditions were found for achieving densification of YSZ at 850°C in a one-step SPS process. In particular, the vacuum level in the SPS chamber is clearly shown to be a decisive parameter to obtain dense nanostructured YSZ tetragonal ceramics up to 95% below 900°C. The occurrence of oxygen vacancies has thus been addressed associating thermal analyses, X-ray photoelectron spectroscopy, Electron Paramagnetic Resonance, photoluminescence spectroscopy and impedance spectroscopy. Understanding defect chemistry mechanisms and their dependence on the process or combination of processes, is a lever towards high-quality YSZ nanostructured ceramics below 900°C