Spectroscopy Of Yb3 Research Articles

Yb3+ Ions Distribution in YAG Nanoceramics Analyzed by Both Optical and TEM-EDX Techniques

We show the approach in the structural and spectroscopic analysis of Yb3+-doped YAG nanoceramics prepared using the low temperature-high pressure sintering technique (LTHP) by conjugation of both TEM-EDX and optical techniques. Pressure sintering dependences of absorption, emission, and decays are analyzed and interpreted. The sample pressurized at 8 GPa for sintering is characterized by the highest transparency and confirms the Y3Al5O12 garnet structure of the grains of ∼21 nm average size. Yb3+ ion distribution has been analyzed by both TEM-EDX evaluation in grains and grain boundaries and spectroscopy of Yb3+ pairs of small population from the co-operative luminescence phenomenon. EDX analysis at the TEM scale provides unambiguous results on a clear tendency of almost uniform Yb3+ distribution. An important new observation has been made at 4 K and room temperature with the 2F7/2 → 2F5/2 0-phonon absorption line located at 975.7 nm, in addition of the 0-phonon line of the YAG structure of grains at 968 ...

Engineering lattice matching, doping level, and optical properties of KY(WO4)2:Gd, Lu, Yb layers for a cladding-side-pumped channel waveguide laser

Single-crystalline KY1-x-y-zGdxLuyYbz(WO4)2 layers are grown onto undoped KY(WO4)2 substrates by liquid-phase epitaxy. The purpose of co-doping the KY(WO4)2 layer with suitable fractions of Gd3+ and Lu3+ is to achieve lattice-matched layers that allow us to engineer a high refractive-index contrast between waveguiding layer and substrate for obtaining tight optical mode confinement and simultaneously accommodate a large range of Yb3+ doping concentrations by replacing Lu3+ ions of similar ionic radius for a variety of optical amplifier or laser applications. Crack-free layers, up to a maximum lattice mismatch of ~0.08 %, are grown with systematic variations of Y3+, Gd3+, Lu3+, and Yb3+ concentrations, their refractive indices are measured at several wavelengths, and Sellmeier dispersion curves are derived. The influence of co-doping on the spectroscopy of Yb3+ is investigated. As evidenced by the experimental results, the lattice constants, refractive indices, and transition cross-sections of Yb3+ in these co-doped layers can be approximated with good accuracy by weighted averages of data from the pure compounds. The obtained information is exploited to fabricate a twofold refractive-index-engineered sample consisting of a highly Yb3+-doped tapered channel waveguide embedded in a passive planar waveguide, and a cladding-side-pumped channel waveguide laser is demonstrated.

Barium borate glass and transparent glass ceramics doped with Pb4Lu2YbF17

Barium borate glasses doped with complex Pb4Lu2YbF17 fluoride have been synthesized and investigated. Heat treatment produced glass ceramics containing the crystalline BaF2:Yb3+ phase. The changes in the structural and optical properties of the glass ceramics were revealed by X-ray diffraction, Raman spectroscopy, and luminescence spectroscopy of Yb3+ ions in polycrystalline Pb4Lu2YbF17, initial glass, and glass ceramics.

Optical properties and upconversion in Yb3+—Tm3+ co-doped oxyfluoride glasses and glass ceramics

Optical spectroscopy of Yb3+ and Tm3+ doped silica based oxyfluoride glass ceramics has been investigated and compared with results for the precursor glasses. Room-temperature absorption, luminescence and upconversion spectra (480, 700 and 800 nm) after infrared excitation at 975 nm have been recorded. From optical absorption spectra, the oscillator strengths have been obtained and used to calculate the Judd-Ofelt parameters. Changes in the spectra of the Yb3+ and Tm3+ ions indicate that the ceramming process modifies the environment of these ions. The dependence of the upconverted emissions on excitation intensity has been measured and from the results obtained the mechanisms involved in the upconversion processes are analysed in the different samples.