J. Appl. Cryst.の発刊に際して

Recent startling interest for lanthanide luminescence is stimulated by the continuously expanding need for luminescent materials meeting the stringent requirements of telecommunication, lighting, electroluminescent devices, (bio-)analytical sensors and bio-imaging set-ups. This critical review describes the latest developments in (i) the sensitization of near-infrared luminescence, (ii) “soft” luminescent materials (liquid crystals, ionic liquids, ionogels), (iii) electroluminescent materials for organic light emitting diodes, with emphasis on white light generation, and (iv) applications in luminescent bio-sensing and bio-imaging based on time-resolved detection and multiphoton excitation (500 references).

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Lanthanide luminescence for functional materials and bio-sciences

Lanthanide-based luminescent hybrid materials.

Upconversion luminescent materials: advances and applications.

An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

Semiconductor device, and manufacturing method thereof

The influence of migration-accelerated energy-transfer upconversion and fast luminescence quenching on Al2O3:Er3+ waveguide amplifiers is investigated. Results indicate that the latter has the stronger impact on the amplifier small-signal gain

Energy-transfer processes in Al2O3:Er3+ waveguide amplifiers

Reflection gratings on Al 2 O 3 channel waveguides were defined by focused ion beam milling. Fabry-Perot microcavities were fabricated and improved performance upon annealing was demonstrated, making them viable candidates as resonators for on-chip waveguide lasers.

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Focused ion beam milled on-chip resonator nanostructures for applications in rare-earth-ion-doped Al 2 O 3 active waveguides

Erbium-doped aluminum oxide (Al2O3:Er) is a promising material for integrated amplifier or tunable laser applications due to its wide gain spectrum around 1550 nm. We deposited Al2O3 layers on thermally oxidized Si-wafers by reactive co-sputtering at 550°C. Propagation losses were 0.11 dB/cm at λ =1.5 μm. Channel waveguides were fabricated by reactive ion etching with propagation losses down to 0.21 dB/cm. Under pumping at 977 nm, the optical small-signal gain at 1533 nm is 0.84 dB/cm, resulting in 5.4 dB net gain over the waveguide length of 6.4 cm. Net gain is obtained over a wavelength range of 41 nm.
The Er concentration was measured using Rutherford Back-Scattering (RBS). Lifetimes of the 4I13/2 level of up to 7 ms were measured for Er concentrations around 2×1020 cm-3. A faster decay with an increasingly non-exponential initial component is measured for higher Er concentrations (Fig. 2). While the initial quenching is probably due to migration-accelerated energy-transfer upconversion between neighboring Er3+ ions in the 4I13/2 level, the decreasing exponential tail is due to either pair-induced energy-transfer upconversion or quenching by impurity ions. Detailed investigations of the quenching mechanisms are currently under way.

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Energy-transfer upconversion in $Al_2O_3:Er^{3+}$ thin layers

We measured Raman spectra of extracted human teeth using an integrated arrayed-waveguide-grating spectrometer fabricated in silicon-oxynitride technology. The results represent a step towards the realization of compact, hand-held, integrated spectrometers for the detection of early dental caries.

On-chip Raman spectrometer for the detection of early dental caries

A channel waveguide laser has been demonstrated by top-loading of a $KY(WO_4)_2:Yb^{3+}$ planar waveguide with a piece of standard optical fibre in combination with contact fluid. Laser emission with a threshold of 85mW and a slope efficiency of 30% has been obtained.

Kerstin Worhoff

Papers

Energy-transfer processes in Al2O3:Er3+ waveguide amplifiers

Focused ion beam milled on-chip resonator nanostructures for applications in rare-earth-ion-doped Al 2 O 3 active waveguides

Energy-transfer upconversion in $Al_2O_3:Er^{3+}$ thin layers

On-chip Raman spectrometer for the detection of early dental caries

Fibre-top-loaded channel waveguide laser in $KY(WO_4)_2:Yb^{3+}$