Jean-Luc Adam

Spectroscopic properties of trivalent lanthanide ions in fluorophosphate glasses

Abstract We describe the spectroscopic properties of the trivalent lanthanide ions Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+ and Yb3+ in the fluorophosphate glasses 75NaPO3–24CaF2–1LnF3 and 75NaPO3–20CaF2–5LnF3 (where Ln=lanthanide ion). Absorption and luminescence spectra are discussed. The dipole strengths of the transitions in the absorption spectrum are parametrized in terms of three Ωλ (λ=2, 4 and 6) Judd–Ofelt intensity parameters. These phenomenological parameters are used to predict the luminescence properties of the lanthanide ions in the fluorophosphate glasses. Attention is paid to the trend of the intensity parameters over the lanthanide series.

Spectroscopic properties and laser emission of Tm doped ZBLAN glass at 1.8 μm

A Tm doped ZBLAN glass is investigated to obtain a laser emission near 1.8 μm instead of classical crystalline host materials. After a brief description of the basic optical properties of Tm doped ZBLAN glass, demonstration of an efficient laser emission in the bulk material is presented. The other investigations are focussed on its wavelength tunability, its tolerance versus the pump wavelength and its behaviour in terms of thermal acceptance which are the main characteristics to consider in order to scale up such laser system.

Low loss microstructured chalcogenide fibers for large non linear effects at 1995 nm

Microstructured optical fibers (MOFs) are traditionally prepared using the stack and draw technique. In order to avoid the interfaces problems observed in chalcogenide glasses, we have developed a new casting method to prepare the chalcogenide preform. This method allows to reach optical losses around 0.4 dB/m at 1.55 µm and less than 0.05 dB/m in the mid IR. Various As(38)Se(62) chalcogenide microstructured fibers have been prepared in order to combine large non linear index of these glasses with the mode control offered by MOF structures. Small core fibers have been drawn to enhance the non linearities. In one of these, three Stokes order have been generated by Raman scattering in a suspended core MOF pumped at 1995 nm.

Optical properties of Tm3+ ions in indium-based fluoride glasses

Abstract Optical properties of Tm 3+ ions in indium-based heavy metal fluoride glasses are studied. Absorption and emission spectra are presented as a function of temperature. Radiative transition rates for the excited states are determined by using the Judd-Ofelt theory. Lifetimes are investigated as a function of temperature and rare-earth concentration for the 1 G 4 and 3 H 4 levels. Cross-relaxation processes are found to be efficient for the 1 G 4 level. For the 3 H 4 level, energy transfer occurs via a two-phonon one-site resonant process.

Photoluminescence of new fluorophosphate glasses containing a high concentration of terbium (III) ions

Abstract Novel fluorophosphate glasses containing a heavy concentration of Tb 3+ ions are studied in terms of optical absorption and emission, and decaytimes. From the 5 D 4 emitting level, an intense green luminescence is observed. The decay is single-exponential whatever the terbium concentration which can be as large as 36 mol%. At high concentrations, a fast diffusion process is responsible for the energy migration from that level. For 5 D 3 , on the other hand, emissions are strongly concentration-dependent, and the decays are well accounted for by the Inokuti-Hirayama model.

Judd-Ofelt intensity parameters of trivalent lanthanide ions in a NaPO3-BaF2 based fluorophosphate glass

Abstract The spectroscopic properties of the trivalent lanthanide ions Pr 3+ , Nd 3+ , Sm 3+ , Eu 3+ , Tb 3+ , Dy 3+ , Ho 3+ , Er 3+ and Tm 3+ in the fluorophosphate glass 75NaPO 3 –24BaF 2 –1LnF 3 (where Ln=lanthanide ion) are described. The dipole strengths of the transitions in the absorption spectrum are parameterised in terms of three Ω λ (λ=2, 4 and 6) Judd–Ofelt intensity parameters.

Fluoride glass research in France: fundamentals and applications

Abstract The paper reviews research activities on fluoride glasses in France over the last 10 years. Glass compositions for industrial applications as well as new glasses from academic research are presented. They include heavy-metal fluoride glasses, fluorochloride glasses and oxyfluoride glasses. Besides physico-chemical properties, special attention is paid to the optical characteristics of heavy-metal fluoride glasses. They exhibit broader infrared transparency than oxides, which results in unique optical properties and applications, especially in the fields of fiber lasers and optical amplifiers operating at wavelengths not accessible with silica.

Site selection spectroscopy in Eu3+-doped fluorozirconate glass

Optical absorption and emission spectra are presented for Eu3+ ions in fluorozirconate (ZBL) glass at room temperature. The energy levels, responsible for the various transitions, are assigned. The point symmetry of the Eu3+ probes is investigated using site selection spectroscopy techniques. Emission and excitation spectra at 4.4 K are presented and two major types of sites are observed. Comparison of the 5D0 → 7F1 and 5D0 → 7F2 intensities suggests that the Eu3+ ion sites have a high symmetry. This is confirmed by decay-time measurements which have been carried out for both glassy and crystalline hosts. Agreement with previous structural results is discussed and a model is proposed.

Optical properties of Eu3+-doped fluorophosphate glasses

Optical absorption spectra of the -doped fluorophosphate glasses 75 (A = Mg, Ca, Ba, Zn), 75 and 58 have been recorded. The dipole strengths are parametrized in terms of three phenomenological Judd-Ofelt intensity parameters (, 4 and 6). With the knowledge of these intensity parameters, the probability for spontaneous emission, the branching ratios and the radiative lifetime are calculated. The relation between the spectral intensities and the glass composition is discussed.

Non-oxide glasses and their applications in optics

The chemical compositions, characteristic temperatures and optical transmission spectra of fluoride and chalcogenide glasses are presented. Properties of rare-earth-doped fluoride glass fiber lasers and amplifiers are given. Passive applications of chalcogenide glass fibers in the infrared are described specifically for optical sensing of chemical species.