Ph. Goldner

EPR and optical study of Yb3+-doped β-PbF2 single crystals and nanocrystals of glass-ceramics

β-PbF2 single crystals doped with YbF3 (0.2% and 2%) were studied by x-ray diffraction (XRD), electron paramagnetic resonance (EPR) and optical spectroscopy. EPR revealed the presence of only one kind of paramagnetic ion Yb3+, in a cubic symmetry site. The optical absorption, emission and excitation spectra enabled us to identify the transitions attributed to Yb3+ in the cubic site and to determine its energy level diagram. Site-selective laser spectroscopy also evidenced the presence of another type of Yb3+ ions, undetectable by classical EPR. This second type, which dominates in the 2%-doped crystal and exhibits cooperative luminescence, was attributed to Yb3+ ions forming clusters. Transparent oxyfluoride glass-ceramics, containing β-Pb1−yYbyF2+y nanocrystallites, were also synthesized and studied by XRD, EPR and optical spectroscopy. Two types of Yb3+ ions were found, as in β-PbF2 single crystals. The optical properties of the oxyfluoride glass-ceramics turn out to be similar to those of ytterbium activated β-PbF2 single crystals. Moreover, the Yb environments found in PbF2 single crystals seem to already occur in the parent glass. Therefore, these materials are expected to be good laser media, like the rare-earth doped fluorite crystals, either in bulk or fibre form.

Internal temperature measurement of an ytterbium doped material under laser operation

Temperature of the pumped volume of an ytterbium doped material has been measured while laser action is taking place. This is achieved by recording green emissions at 530 and 550 nm from Er3+ impurities. These emissions result from energy transfer upconversion processes between Yb3+ and Er3+. Experiments performed on a Yb3+:CaGdAlO4 crystal show the effect of pump power and laser wavelength on the sample internal temperature. Temperature variation along the sample length has also been measured. This method can complement data obtained by thermal cameras which can only access surface temperatures in most laser materials.

Experimental tailoring of a three-level Λ system in Tm 3 + : YAG

Quantum information transfer from light to atom ensembles and vice versa has both basic and practical importance. Among the relevant topics let us mention entanglement and decoherence of macroscopic systems, together with applications to quantum memory for long distance quantum cryptography. Although the first experimental demonstrations have been performed in atomic vapors and clouds, rare earth ion doped crystals are also interesting media for such processes. In this paper we address

Photon avalanche fluorescence and lasers

{\mathrm{Tm}}^{3+}

A practical analysis of electron paramagnetic resonance spectra of rare earth ion pairs

ions capability to behave as three-level

Site selection and up-conversion studies in erbium and ytterbium doped CsCdBr3

\ensuremath{\Lambda}

The blue up-conversion luminescence of vitroceramics codoped with Tm3+ and Yb3+ ions pumped with 680 nm

systems, a key ingredient to convert optical excitation into a spontaneous-emission-free spin wave. Indeed

Optical excitation of nuclear spin coherence in a Tm 3+ :YAG crystal

{\mathrm{Tm}}^{3+}

Branching ratio measurement of a Λ system in Tm 3 + : YAG under a magnetic field

falls within reach of light sources that can be stabilized easily to the required degree. In the absence of zero-field hyperfine structure we apply an external magnetic field to lift the nuclear spin degeneracy in

Theoretical evaluation of cooperative luminescence rate in Yb3+: CsCdBr3 and comparison with experiment

{\mathrm{Tm}}^{3+}:\mathrm{YAG}