Tinkerbell beams in a non-linear ring resonator

AbstractIn this article the dynamical behaviour of a beam that behaves according to a Tinkerbell map (i.e. Tinkerbell beam), within a nonlinear ring phase-conjugated resonator is modelled. The ABCD matrix of an optical device able to generate a two dimensional Tinkerbell map is found in terms of the map parameters, the state variables and the resonator parameters. For the first time to our knowledge the conditions in order to obtain the dynamics of a beam behaving according to a Tinkerbell map are found within an optical resonator. Finally some of the main technical problems to build a resonator intracavity element able to produce Tinkerbell beams are presented

Excited-state absorption in erbium-doped silica fiber with simultaneous excitation at 977 and 1531 nm

We report a study of the excited-state absorption (ESA) in erbium-doped silica fiber (EDF) pumped at 977 nm, when the fiber is simultaneously excited by signal radiation at 1531 nm. We show, both experimentally and theoretically, that ESA efficiency at 977 nm gets strongly enhanced only in the presence of signal power. Experimentally, this conclusion is supported through the detection of upconversion emission, a “fingerprint” of the ESA process, and through the measurements of the EDF nonlinear transmission coefficient for the pump wavelength, which is sensitive to the ESA value. It is shown that the experimental data are precisely modeled with an advanced five-level Er3+ model developed for the [email protected] [email protected]

Upconversion assisted self-pulsing in a high-concentration erbium doped fiber laser

We report results on experimental and theoretical characterisation of self-pulsing in high concentration erbium doped fibre laser which is free from erbium clusters. Unlike previous models of self-pulsing accounting for pair-induced quenching (PIQ) on the clustered erbium ions, new model has been developed with accounting for statistical nature of the excitation migration and upconversion and resonance-like pumpto-signal intensity noise transfer. The obtained results are in a good agreement with the experimental data

Nanocrystalline lanthanide-doped Lu3Ga5O12 garnets: interesting materials for light-emitting devices

Nanocrystalline Lu3Ga5O12, with average particle sizes of 40 nm, doped with a wide variety of luminescent trivalent lanthanide ions have been prepared using a sol\u2013gel technique. The structural and morphological properties of the powders have been investigated by x-ray powder diffraction, high resolution transmission electron microscopy and Raman spectroscopy. Structural data have been refined and are presented for Pr3+, Eu3+, Gd3+, Ho3+, Er3+ and Tm3+ dopants, while room temperature excited luminescence spectra and emission decay curves of Eu3+-, Tm3+- and Ho3+-doped Lu3Ga5O12 nanocrystals have been measured and are discussed. The Eu3+ emission spectrum shows typical bands due to 5D0 \u21927FJ (J = 0, 1, 2, 3, 4) transitions and the broadening of these emission bands with the non-exponential behaviour of the decay curves indicates the presence of structural disorder around the lanthanide ions. Lanthanide-doped nanocrystalline Lu3Ga5O12 materials show better luminescence intensities compared to Y2O3, Gd3Ga5O12 and Y3Al5O12 nanocrystalline hosts. Moreover, the upconversion emission intensity in the blue-green region for the Tm3+- and Ho3+-doped samples shows a significant increase upon 647.5 nm excitation with respect to other common oxide hosts doped with the same lanthanide ions

Structural and luminescence investigation on gadolinium gallium garnet nanocrystalline powders prepared by solution combustion synthesis

Nanocrystalline powders of undoped and lanthanide (Pr3+, Tm3+)- doped gadolinium gallium garnet, Gd3Ga5O12 (GGG), were prepared by propellant synthesis and studied by x-ray powder diffraction (XRD), electron diffraction (ED), high-resolution electron microscopy (HREM) and luminescence spectroscopy. The x-ray diffraction patterns of the GGG samples were analysed using the Rietveld method. The Rietveld refinement reveals the existence of two garnet-type phases: both are cubic (space group Ia $(3) over bar$d) with a slightly different lattice parameter and probably a slightly different composition. Electron diffraction and electron microscopy measurements confirm the x-ray diffraction results. EDX measurements for lanthanide-doped samples show that stable solid solutions with composition Gd(3-x)Ln(x)Ga(5)O(12), x approximate to 0.3 ( Ln = Pr; Tm) have been obtained. The luminescence properties of the Tm3+ -doped nanocrystalline GGG samples were measured and analysed