Optical And Physical Properties Of Er3+-yb3+ Co-doped Tellurite Fibers

In this work we present results of physical and optical properties of Er3+-Yb3+ co-doped tellurite glasses and fibers. The Double Clad Tellurite Fibers (DCTFs) are based on glasses with the composition: TeO2-WO3-Nb2O5-Na 2O-Al2O3-Er2O3-Yb 2O3. The DCTFs were fabricated by using the rod-in-tube technique and a Heathway drawing tower. The optical absorption spectra (ranging from 350 to 1750 nm) of these fibers were measured using an Optical Spectrum Analyzer (OSA). The emission spectra, around 1550 nm band, of these fibers (lengths varying from 1 to 60 cm) were obtained by using a 980nm diode laser pump. The optimal Amplified Spontaneous Emission (ASE) spectra were observed for fiber lengths ranging from 2 to 6 cm. The Er 3+/Yb3+ co-doped DCTFs show an efficient up-conversion process in comparison with the Er3+-doped DCTF. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).8120The Society of Photo-Optical Instrumentation Engineers (SPIE)Murugan, G.S., Suzuki, T., Ohishi, Y., Raman characteristics and nonlinear optical properties of tellurite and phosphotellurite glasses containing heavy metal oxides with ultrabroad Raman bands (2006) J. of Appl. Phys., 100, p. 023107Nandi, P., Jose, G., Ytterbium-doped P2O5-TeO2 glass for laser applications (2006) IEEE J. of Quat. Electron., 42, pp. 1115-1121Man, S.Q., Pun, E.Y.B., Chung, P.S., Tellurite glasses for 1.3 mm optical amplifiers" (1999) Opt. Comm., 168, pp. 369-373Wang, J.S., Vogel, E.M., Snitzer, E., Tellurite Glass: A New Candidate for Fiber Devices" (1994) Opt. Mat., 3, pp. 187-203Xu, S., Sun, H., Dai, S., Zhang, J., Jiang, Z., Upconversion luminescence of Tm3+/Yb3+-codoped oxyhalide tellurite glasses" (2005) Sol. St. Comm., 133, pp. 89-92Bookey, H.T., Lousteau, J., Jha, A., Gayraud, N., Thomson, R.R., Psaila, N.D., Li, H., Kar, A.K., Multiple rare earth emissions in a multicore tellurite fiber with a single pump wavelength" (2007) Opt. Express, 15, pp. 17554-17561Qin, G., Mori, A., Ohishi, Y., Brillouin lasing in a single-mode tellurite fiber" (2007) Opt. Lett., 32, pp. 2179-2181Zweig, A.D., Frenz, M., Romano, V., Weber, H.P., A comparative study of laser tissue interaction at 2.94 μm and 10.6 μm" (1988) Appl. Phys. B, 47, pp. 259-265Zhang, J., Dai, S., Wang, G., Sun, H., Zhang, L., Hu, L., Fabrication and emission properties of Er3+/Yb3+ codoped tellurite glass fiber for broadband optical amplification (2005) J. of Lum., 115, pp. 45-52Shixun, D., Tiefeng, X., Qiuhua, N., Xiang, S., Xunsi, W., Fabrication and gain performance of Er3+/Yb3+-codoped tellurite glass fiber (2008) J. of Rare Earths, 26, pp. 915-918Jakutis, J., Gomes, L., Amancio, C.T., Kassab, L.R.P., Martinelli, J.R., Wetter, N.U., Increased Er3+ upconversion in tellurite fibers and glasses by co-doping with Yb3+ (2010) Opt. Mat., 33, pp. 107-111Hruby, A., Evaluation of glass-forming tendency by means of DTA (1972) Czech J. Phys B, 22, pp. 1187-119

Search for supersymmetry with a dominant R-parity violating LQDbar couplings in e+e- collisions at centre-of-mass energies of 130GeV to 172 GeV

A search for pair-production of supersymmetric particles under the assumption that R-parity is violated via a dominant LQDbar coupling has been performed using the data collected by ALEPH at centre-of-mass energies of 130-172 GeV. The observed candidate events in the data are in agreement with the Standard Model expectation. This result is translated into lower limits on the masses of charginos, neutralinos, sleptons, sneutrinos and squarks. For instance, for m_0=500 GeV/c^2 and tan(beta)=sqrt(2) charginos with masses smaller than 81 GeV/c^2 and neutralinos with masses smaller than 29 GeV/c^2 are excluded at the 95% confidence level for any generation structure of the LQDbar coupling.Comment: 32 pages, 30 figure

Search for the glueball candidates f0(1500) and fJ(1710) in gamma gamma collisions

Data taken with the ALEPH detector at LEP1 have been used to search for gamma gamma production of the glueball candidates f0(1500) and fJ(1710) via their decay to pi+pi-. No signal is observed and upper limits to the product of gamma gamma width and pi+pi- branching ratio of the f0(1500) and the fJ(1710) have been measured to be Gamma_(gamma gamma -> f0(1500)). BR(f0(1500)->pi+pi-) < 0.31 keV and Gamma_(gamma gamma -> fJ(1710)). BR(fJ(1710)->pi+pi-) < 0.55 keV at 95% confidence level.Comment: 10 pages, 3 figure

Search for supersymmetry in the photon(s) plus missing energy channels at s\sqrt{s}=161 GeV and 172 GeV

Searches for supersymmetric particles in channels with one or more photons and missing energy have been performed with data collected by the ALEPH detector at LEP. The data consist of 11.1 \pb\ at $\sqrt{s} = 161 ~\, \rm GeV$, 1.1 \pb\ at 170 \gev\ and 9.5 \pb\ at 172 GeV. The \eenunu\ cross se ction is measured. The data are in good agreement with predictions based on the Standard Model, and are used to set upper limits on the cross sections for anomalous photon production. These limits are compared to two different SUSY models and used to set limits on the neutralino mass. A limit of 71 \gevsq\ at 95\% C.L. is set on the mass of the lightest neutralin o ($\tau_{\chi_{1}^{0}} \leq$ 3 ns) for the gauge-mediated supersymmetry breaking and LNZ models

Search for Bs0B^{0}_{s} oscillations using inclusive lepton events

A search for Bs oscillations is performed using a sample of semileptonic b-hadron decays collected by the ALEPH experiment during 1991-1995. Compared to previous inclusive lepton analyses, the prop er time resolution and b-flavour mistag rate are significantly improved. Additional sensitivity to Bs mixing is obtained by identifying subsamples of events having a Bs purity which is higher than the average for the whole data sample. Unbinned maximum likelihood amplitude fits are performed to derive a lower limit of Dms>9.5 ps-1 at 95% CL. Combining with the ALEPH Ds based analyses yields Dms>9.6 ps-1 at 95% CL.A search for B0s oscillations is performed using a sample of semileptonic b-hadron decays collected by the ALEPH experiment during 1991-1995. Compared to previous inclusive lepton analyses, the proper time resolution and b-flavour mistag rate are significantly improved. Additional sensitivity to B0s mixing is obtained by identifying subsamples of events having a B0s purity which is higher than the average for the whole data sample. Unbinned maximum likelihood amplitude fits are performed to derive a lower limit of Deltam_s>9.5ps^-1 at 95% CL. Combining with the ALEPH D-s based analyses yields Deltam_s>9.6ps^-1 at 95% CL

Measurement of the tau lepton lifetime with the three-dimensional impact parameter method.

A new method is presented for the measurement of the mean $\tau$ lepton lifetime using events in which $\tau$'s are pair-produced and both $\tau$'s decay to hadrons and $\nu_\tau$. Based on the correlation between the two $\tau$'s produced at a symmetric $e^+ e^-$ collider, the 3DIP method relies on the three-dimensional information from a double-sided vertex detector and on kinematic constraints for the precise measurement of the $\tau$ decay angles. Using the data collected from 1992 to 1994 with the ALEPH detector at LEP, a $\tau$ lifetime of $288.0 \pm 3.1 \pm 1.3$\fs is obtained from the sample in which both $\tau$'s decay to one charged track, and $292.8 \pm 5.6 \pm 3.0$\fs from the sample in which one $\tau$ decays to one prong and the other to three prongs. The results show small statistical correlations with those derived from other methods. When combined with the previously published ALEPH measurements, the resulting $\tau$ lifetime is $291.2 \pm 2.0 \pm 1.2$\fs

Measurement of the tau lepton lifetime with the three-dimensional impact parameter method.

A new method is presented for the measurement of the mean $\tau$ lepton lifetime using events in which $\tau$'s are pair-produced and both $\tau$'s decay to hadrons and $\nu_\tau$. Based on the correlation between the two $\tau$'s produced at a symmetric $e^+ e^-$ collider, the 3DIP method relies on the three-dimensional information from a double-sided vertex detector and on kinematic constraints for the precise measurement of the $\tau$ decay angles. Using the data collected from 1992 to 1994 with the ALEPH detector at LEP, a $\tau$ lifetime of $288.0 \pm 3.1 \pm 1.3$\fs is obtained from the sample in which both $\tau$'s decay to one charged track, and $292.8 \pm 5.6 \pm 3.0$\fs from the sample in which one $\tau$ decays to one prong and the other to three prongs. The results show small statistical correlations with those derived from other methods. When combined with the previously published ALEPH measurements, the resulting $\tau$ lifetime is $291.2 \pm 2.0 \pm 1.2$\fs

Measurement of the tau lepton lifetime with the three-dimensional impact parameter method.

A new method is presented for the measurement of the mean $\tau$ lepton lifetime using events in which $\tau$'s are pair-produced and both $\tau$'s decay to hadrons and $\nu_\tau$. Based on the correlation between the two $\tau$'s produced at a symmetric $e^+ e^-$ collider, the 3DIP method relies on the three-dimensional information from a double-sided vertex detector and on kinematic constraints for the precise measurement of the $\tau$ decay angles. Using the data collected from 1992 to 1994 with the ALEPH detector at LEP, a $\tau$ lifetime of $288.0 \pm 3.1 \pm 1.3$\fs is obtained from the sample in which both $\tau$'s decay to one charged track, and $292.8 \pm 5.6 \pm 3.0$\fs from the sample in which one $\tau$ decays to one prong and the other to three prongs. The results show small statistical correlations with those derived from other methods. When combined with the previously published ALEPH measurements, the resulting $\tau$ lifetime is $291.2 \pm 2.0 \pm 1.2$\fs

Measurement of the tau lepton lifetime with the three-dimensional impact parameter method.

A new method is presented for the measurement of the mean $\tau$ lepton lifetime using events in which $\tau$'s are pair-produced and both $\tau$'s decay to hadrons and $\nu_\tau$. Based on the correlation between the two $\tau$'s produced at a symmetric $e^+ e^-$ collider, the 3DIP method relies on the three-dimensional information from a double-sided vertex detector and on kinematic constraints for the precise measurement of the $\tau$ decay angles. Using the data collected from 1992 to 1994 with the ALEPH detector at LEP, a $\tau$ lifetime of $288.0 \pm 3.1 \pm 1.3$\fs is obtained from the sample in which both $\tau$'s decay to one charged track, and $292.8 \pm 5.6 \pm 3.0$\fs from the sample in which one $\tau$ decays to one prong and the other to three prongs. The results show small statistical correlations with those derived from other methods. When combined with the previously published ALEPH measurements, the resulting $\tau$ lifetime is $291.2 \pm 2.0 \pm 1.2$\fs