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E Y B Pun - One of the best experts on this subject based on the ideXlab platform.

  • superbroadband near ir emission from praseodymium doped Bismuth Gallate glasses
    Optics Letters, 2011
    Co-Authors: Bo Zhou, E Y B Pun
    Abstract:

    Superbroadband near-infrared (NIR) emission covering 1250 to 1680 nm wavelength has been obtained in praseodymium (Pr3+) singly doped Bismuth Gallate glasses. The emission originates from the G41→H53 and D21→G41 transitions at 1330 and 1490 nm wavelengths, respectively, and is due to the extremely low phonon energy (∼690 cm−1) and the unique ligand field of the glasses. It is shown that the emission line shape can be modified by adjusting the Pr3+ concentration and the energy transfers involved. The results confirm that other than Bismuth (Bi), chromium (Cr), nickel (Ni), and other chemical elements, Pr3+ singly doped system is a promising alternative in achieving superbroadband NIR emission.

  • fluorescence investigation of ho3 in yb3 sensitized mixed alkali Bismuth Gallate glasses
    Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2008
    Co-Authors: H Lin, Y Y Zhang, E Y B Pun
    Abstract:

    Abstract Efficient 2.0 μm infrared and visible upconversion emissions have been observed in Ho3+/Yb3+ co-doped mixed-alkali Bismuth Gallate (LKBBG) glasses having a maximum-phonon energy of 673 cm−1. The Judd–Ofelt parameters Ω2, Ω4 and Ω6 of Ho3+ indicate that there is a high asymmetry and strong covalent environment in LKBBG glasses. The large absorption and emission cross-sections of Yb3+ confirm that it is a suitable sensitizer for capturing and transferring pump energy to Ho3+. The emission cross-section profile for the 5I7 → 5I8 transition is derived using the reciprocity method and the peak value is 5.54 × 10−21 cm2, which is much larger than the value in fluorozircoaluminate glasses. LKBBG glasses exhibit low maximum-phonon energy and large refractive index, and it is possible to achieve an effective 1.66 μm U-band emission of Ho3+ under 900nm laser radiation.

  • powerful visible upconversion fluorescence of er3 in novel Bismuth Gallate glasses compared with in common tellurite glasses
    Journal of Alloys and Compounds, 2008
    Co-Authors: H X Yang, H Lin, L Lin, Yan Zhang, B Zhai, E Y B Pun
    Abstract:

    Abstract Powerful visible upconversion fluorescence intensities of Er3+ in novel Bismuth Gallate glasses (LKBBG) and common tellurite glasses (TZN) with low phonon energies and high refractive indices have been compared. Under the same measurement condition, Er3+-doped LKBBG glasses show the stronger upconversion emission intensities than Er3+-doped common tellurite glasses (TZN). The visible upconversion emission bands peaked at 531, 548 and 668 nm have been confirmed that two photons contribute to these upconversion processes. The maximum phonon energy obtained in LKBBG glasses is 673 cm−1, which is 65 cm−1 lower than that in common tellurite glasses, indicating that LKBBG glasses almost possess the lowest maximum phonon energy in all of the oxide glasses. All analyses support that Er3+-doped LKBBG glasses are promising materials for fabricating visible upconversion devices.

  • 1 47 µm emission and multiphonon relaxation of tm 3 ions in potassium Bismuth Gallate glasses
    Journal of The Optical Society of America B-optical Physics, 2004
    Co-Authors: Shi Qing Man, E Y B Pun, Sun Fat Wong, P S Chung
    Abstract:

    We propose and demonstrate potassium Bismuth Gallate (KBG) glasses as suitable hosts for the rare-earth ion Tm3+ (thulium) operating at the 1.47-μm wavelength. The optical properties of Tm3+-doped KBG glasses were investigated. The bandwidth of the 3H4→3F4 transition is ∼120 nm and is higher than that of Tm3+-doped, tellurite-based glasses. The measured fluorescence lifetime is 0.15 ms at room temperature, and the quantum efficiency is 88%. Multiphonon relaxation rates for various transitions were evaluated and compared with other glass hosts. The energy transfer in Tm3+–Ho3+-codoped KBG glasses was also investigated, and these results indicate that Tm3+-doped KBG glasses are promising candidates for efficient broadband optical amplifiers operating in the 1.47-μm wavelength range.

  • erbium doped potassium Bismuth Gallate glasses
    Journal of The Optical Society of America B-optical Physics, 2002
    Co-Authors: S Q Man, Sun Fat Wong, E Y B Pun
    Abstract:

    We demonstrate potassium Bismuth Gallate glasses as suitable hosts for rare-earth-ion erbium (Er3+) operating in the 1.55-µm-wavelength region. The absorption and luminescence spectra along with the luminescence decay time were measured. The emission peak of the  4I13/2→4I15/2 transition is at the 1.53-µm wavelength, and the spectral bandwidth is 85 nm, which is one of the broadest. The lifetime of the  4I13/2 level is ∼2.42 ms, and the quantum efficiency is ∼100%. The emission cross section is estimated to be ∼12.4×10-21 cm2, which is one of the highest among different oxide glasses. The gain coefficient is also calculated, and our results show that potassium Bismuth Gallate glasses are excellent host materials for broadband-amplifier and high-power-laser applications.

P S Chung - One of the best experts on this subject based on the ideXlab platform.

  • 1 47 µm emission and multiphonon relaxation of tm 3 ions in potassium Bismuth Gallate glasses
    Journal of The Optical Society of America B-optical Physics, 2004
    Co-Authors: Shi Qing Man, E Y B Pun, Sun Fat Wong, P S Chung
    Abstract:

    We propose and demonstrate potassium Bismuth Gallate (KBG) glasses as suitable hosts for the rare-earth ion Tm3+ (thulium) operating at the 1.47-μm wavelength. The optical properties of Tm3+-doped KBG glasses were investigated. The bandwidth of the 3H4→3F4 transition is ∼120 nm and is higher than that of Tm3+-doped, tellurite-based glasses. The measured fluorescence lifetime is 0.15 ms at room temperature, and the quantum efficiency is 88%. Multiphonon relaxation rates for various transitions were evaluated and compared with other glass hosts. The energy transfer in Tm3+–Ho3+-codoped KBG glasses was also investigated, and these results indicate that Tm3+-doped KBG glasses are promising candidates for efficient broadband optical amplifiers operating in the 1.47-μm wavelength range.

  • upconversion luminescence of er3 in alkali Bismuth Gallate glasses
    Applied Physics Letters, 2000
    Co-Authors: P S Chung
    Abstract:

    Frequency upconversion of Er3+ in alkali Bismuth Gallate glasses have been investigated. The upconversion mechanisms are discussed, and the dominant mechanisms are excited state absorption for the 2H11/2→4I15/2 and 4S3/2→4I15/2 transitions, and energy transfer upconversion for the 4F9/2→4I15/2 transition. Intense green (around 525–550 nm) and red (around 660 nm) emission bands were observed under 800 nm excitation. At a pump intensity of 15.6 W/cm2, frequency upconversion efficiencies of 2.1×10−2 and 4.8×10−3 were obtained for the green and red emissions, respectively. The results are the highest among doped oxide glasses, and are comparable to those reported for Er3+/Yb3+ codoped fluoride glasses.

  • praseodymium doped alkali Bismuth Gallate glasses
    Journal of The Optical Society of America B-optical Physics, 2000
    Co-Authors: S Q Man, E Y B Pun, P S Chung
    Abstract:

    We propose and demonstrate alkali Bismuth Gallate glasses as suitable hosts for the rare earth praseodymium (Pr3+) operating at 1.3-µm wavelength. The structure of the glasses was investigated by Raman spectroscopy. The optical absorption and the photoluminescence properties of Pr3+ in these glasses were characterized. The Raman spectrum shows two strong peaks, at 134 and 381 cm-1, and a weak peak at 660 cm-1. The results indicate that Bismuth (Bi3+) and gallium (Ga3+) cations do take part in the formation of the glass network. The emission from the Pr3+: 1G4→3H5 transition is at 1.34-µm wavelength, and the spectral bandwidth is 120 nm, which is wider than those of fluoride and chalcogenide glasses. The lifetime of the  1G4 level is ∼78 µs, and the quantum efficiency is ∼17.4%, which is higher than that in fluoride glasses.

  • frequency upconversion in er sup 3 doped alkali Bismuth Gallate glasses
    Lasers and Electro-Optics Society Meeting, 1999
    Co-Authors: S Q Man, E Y B Pun, R S F Wong, P S Chung
    Abstract:

    Upconversion of infrared light to visible light in rare earth ions doped glasses and crystals have been extensively investigated due to their applications in the areas of color display, optical data storage, optoelectronics, medical diagnostics and undersea optical communications. Upconversion is difficult to generate in conventional oxide glasses due to the high phonon energies corresponding to the high vibration energies of the oxide glass networks. However, oxide glasses have high chemical stability and ease of fabrication. Upconversion fluorescence has been reported in Er/sup 3+/ doped TeO/sub 2/-Na/sub 2/O and TeO/sub 2/-PbO glasses. However, the upconversion efficiency is poor due to the high phonon energies inherent in tellurite glasses (700 - 800 cm/sup -1/. The properties of KBG glasses were characterized, and comparison was made with tellurite K/sub 2/O-ZnO-TeO/sub 2/ (KZT) glasses. The upconversion fluorescence of Er/sup 3+/ in alkali Bismuth Gallate (KBG) glasses was investigated, and optical waveguides were demonstrated in these oxide glasses using the ion-exchange process.

  • alkali Bismuth Gallate glasses for 1 3 µm planar optical amplifiers
    Integrated Photonics Research (1999) paper RMF2, 1999
    Co-Authors: S Q Man, E Y B Pun, P S Chung
    Abstract:

    At present, there are three principal rare earth candidates for 1.3 µm optical amplifiers: neodymium (Nd3+), praseodymium (Pr3+) and dysprosium (Dy3+).

S Q Man - One of the best experts on this subject based on the ideXlab platform.

  • erbium doped potassium Bismuth Gallate glasses
    Journal of The Optical Society of America B-optical Physics, 2002
    Co-Authors: S Q Man, Sun Fat Wong, E Y B Pun
    Abstract:

    We demonstrate potassium Bismuth Gallate glasses as suitable hosts for rare-earth-ion erbium (Er3+) operating in the 1.55-µm-wavelength region. The absorption and luminescence spectra along with the luminescence decay time were measured. The emission peak of the  4I13/2→4I15/2 transition is at the 1.53-µm wavelength, and the spectral bandwidth is 85 nm, which is one of the broadest. The lifetime of the  4I13/2 level is ∼2.42 ms, and the quantum efficiency is ∼100%. The emission cross section is estimated to be ∼12.4×10-21 cm2, which is one of the highest among different oxide glasses. The gain coefficient is also calculated, and our results show that potassium Bismuth Gallate glasses are excellent host materials for broadband-amplifier and high-power-laser applications.

  • praseodymium doped alkali Bismuth Gallate glasses
    Journal of The Optical Society of America B-optical Physics, 2000
    Co-Authors: S Q Man, E Y B Pun, P S Chung
    Abstract:

    We propose and demonstrate alkali Bismuth Gallate glasses as suitable hosts for the rare earth praseodymium (Pr3+) operating at 1.3-µm wavelength. The structure of the glasses was investigated by Raman spectroscopy. The optical absorption and the photoluminescence properties of Pr3+ in these glasses were characterized. The Raman spectrum shows two strong peaks, at 134 and 381 cm-1, and a weak peak at 660 cm-1. The results indicate that Bismuth (Bi3+) and gallium (Ga3+) cations do take part in the formation of the glass network. The emission from the Pr3+: 1G4→3H5 transition is at 1.34-µm wavelength, and the spectral bandwidth is 120 nm, which is wider than those of fluoride and chalcogenide glasses. The lifetime of the  1G4 level is ∼78 µs, and the quantum efficiency is ∼17.4%, which is higher than that in fluoride glasses.

  • frequency upconversion in er sup 3 doped alkali Bismuth Gallate glasses
    Lasers and Electro-Optics Society Meeting, 1999
    Co-Authors: S Q Man, E Y B Pun, R S F Wong, P S Chung
    Abstract:

    Upconversion of infrared light to visible light in rare earth ions doped glasses and crystals have been extensively investigated due to their applications in the areas of color display, optical data storage, optoelectronics, medical diagnostics and undersea optical communications. Upconversion is difficult to generate in conventional oxide glasses due to the high phonon energies corresponding to the high vibration energies of the oxide glass networks. However, oxide glasses have high chemical stability and ease of fabrication. Upconversion fluorescence has been reported in Er/sup 3+/ doped TeO/sub 2/-Na/sub 2/O and TeO/sub 2/-PbO glasses. However, the upconversion efficiency is poor due to the high phonon energies inherent in tellurite glasses (700 - 800 cm/sup -1/. The properties of KBG glasses were characterized, and comparison was made with tellurite K/sub 2/O-ZnO-TeO/sub 2/ (KZT) glasses. The upconversion fluorescence of Er/sup 3+/ in alkali Bismuth Gallate (KBG) glasses was investigated, and optical waveguides were demonstrated in these oxide glasses using the ion-exchange process.

  • alkali Bismuth Gallate glasses for 1 3 µm planar optical amplifiers
    Integrated Photonics Research (1999) paper RMF2, 1999
    Co-Authors: S Q Man, E Y B Pun, P S Chung
    Abstract:

    At present, there are three principal rare earth candidates for 1.3 µm optical amplifiers: neodymium (Nd3+), praseodymium (Pr3+) and dysprosium (Dy3+).

G A Kumar - One of the best experts on this subject based on the ideXlab platform.

J G Eden - One of the best experts on this subject based on the ideXlab platform.

  • fluorescence and upconversion spectral studies of ho3 in alkali Bismuth Gallate glasses
    Journal of Alloys and Compounds, 2004
    Co-Authors: G A Kumar, A Martinez, E B Mejia, J G Eden
    Abstract:

    Abstract The absorption and emission spectra of Ho3+ in alkali Bismuth Gallate glass matrices have been investigated in the visible and near-infrared. Strong fluorescence in the green (λ∼549 nm), arising from the 5S2→5I8 transition of the ion, has been observed when Ho-doped potassium Bismuth Gallate glass is optically-excited in the red (∼646 nm). The measured quadratic dependence of the relative 549 nm intensity on pump power demonstrates that the upconversion mechanism is the sequential absorption of two photons. For a pump power of 285 mW at 646 nm, the upconversion efficiency is measured to be 5.5% which is among the highest values reported for glassy or crystalline matrices.