| Jun 27, 2012 |
Novel crystals for optical devices
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(Nanowerk News) EU-funded researchers investigated novel nano-crystalline structures for potential use in a variety of laser and imaging devices related to biology, medicine and defence.
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Most people are familiar with a simple prism that separates visible light into its individual colour components corresponding to specific wavelengths and frequencies. The impending light sort of ‘fans out’ to show the individual components by the dispersion properties of the glass.
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Crystals are another type of structure with interesting properties with respect to impending light. In fact, crystal chemistry is a branch of chemistry that describes the structures and functions of various crystalline structures and glass.
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Solids consisting of (primarily) repeating patterns of atoms, crystals can be ‘grown’ to produce various three-dimensional (3D) structures with specific properties depending on the atoms present.
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Solid-state lasers rely on crystals or glasses as gain media to amplify light at the laser’s wavelength. To do so, they employ doping with metal ions, often from the lanthanide or rare earth series.
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Rare-earth ion-doped double tungstates (DTs) have been extensively investigated recently. They demonstrate both efficient emission in the visible and infrared regions of the electromagnetic spectrum and have multifunctional properties.
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Multifunctional materials exhibit specific functionalities including unconventional superconductivity, piezo- and ferro-electricity. Rare-earth DTs have recently been shown to exhibit magnetostriction, or elastic changes in the presence of a magnetic field. They have been implicated for use in optical storage or imaging devices.
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European researchers supported by funding of the ‘Double tungstate crystals: synthesis, characterisation and applications’ (DT-CRYS) project set out to synthesise DTs in various geometries and to evaluate their properties. Of interest were structural, thermomechanical, optical and magnetic characteristics as well as resistivity and wave-guiding abilities.
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The goal was to enable tailoring of composition, doping and geometry of DTs for specific applications in material processing, biomedicine and biology and defence.
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Researchers successfully synthesised highly homogeneous DT nanopowders as well as bulk crystals and thin-film–doped layers. Waveguide structures and numerous designs for laser devices based on the DTs were also produced. Finally, non-linear properties of the multifunctional DTs were evaluated for potential use in wavelength conversion devices.
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DT-CRYS project results should have important implications for a variety of new laser devices with novel properties. This could open the door to tailor-made functional crystals for use in other fields such as biology, medicine and defence.
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