| 1. |
- Canalias, Carlota, et al.
(author)
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In situ visualization of domain kinetics in flux grown KTiOPO4 by digital holography
- 2007
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 102:6, s. 064105-
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Journal article (peer-reviewed)abstract
- The fast dynamic evolution of ferroelectric domains during electric field poling in flux grown KTiOPO4 crystals was investigated online by a digital holography based technique. The dependence of the ferroelectric domain kinetics on the electric field temporal wave form and poling history was studied. High-speed imaging by means of a complementary metal-oxide-semiconductor image sensor camera allowed in situ measurement of the domain wall propagation speed under different poling conditions. The results also give evidence of the strong influence of the dielectric surface layer in this material.
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| 2. |
- Grilli, Simonetta, et al.
(author)
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Control of lateral domain spreading in congruent lithium niobate by selective proton exchange
- 2006
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In: Applied physics letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 89:3, s. 032902-
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Journal article (peer-reviewed)abstract
- Proton exchange was observed to increase the poling voltage for congruent lithium niobate. Patterned proton exchange was then used to control domain nucleation and inhibit broadening of reversed domains. Periodically proton exchanged samples were used to form domain gratings by electric field poling just using planar electrodes and without need for poling current control. The reversed domain gratings had a duty cycle faithfully reproducing that of the proton exchanged pattern with straight domain walls parallel to the x face, thus demonstrating that high-fidelity reversed domain patterning is possible to obtain by a relatively simple process.
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| 3. |
- Grilli, Simonetta, et al.
(author)
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Double-face and submicron two-dimensional domain patterning in congruent lithium niobate
- 2006
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In: IEEE photonics technology letters. - 1041-1135. ; 18, s. 541-
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Journal article (peer-reviewed)abstract
- We report on the simultaneous fabrication of two-dimensional submicron engineered domain patterns on both crystal faces, in congruent lithium niobate. The fabrication technique is based on interference photolithography, which allows short pitch over large areas, followed by electric field poling performed in overpoling regime. Experimental results for different domain pattern geometries, on the two crystal faces, are reported. These structures could be useful for short-wavelength frequency conversion and Bragg gratings applications. The moire effect is used in the lithographic process to fabricate more complex structures which could find application in photonic bandgap devices.
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| 4. |
- Grilli, SImonetta, et al.
(author)
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Surface nanoscale periodic structures in congruent lithium niobate by domain reversal patterning and differential etching
- 2005
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In: Applied physics letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 87, s. 233106-
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Journal article (peer-reviewed)abstract
- We report on the fabrication and characterization of one- and two-dimensional periodic structures down to 200 nm size, in congruent lithium niobate crystal samples. Periods from 2 mu m to 530 nm are investigated. Interference photolithography is used to obtain short pitch insulating gratings, and subsequent electric-field poling, at the overpoling regime, is performed for periodic domain inversion. Nanoscale structures are obtained by selective chemical etching, and topographic investigations are performed by atomic force microscope. The fabricated structures are attractive in nonlinear optics for short-wavelength conversion and in the field of photonic crystals for Bragg and band-gap applications
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| 5. |
- Paturzo, M., et al.
(author)
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On the origin of internal field in lithium niobate crystals directly observed by digital holography
- 2005
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In: Optics express. - 1094-4087. ; 13:14, s. 5416-
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Journal article (peer-reviewed)abstract
- We show the defect dependence of the internal field in Lithium Niobate using a full-field interferometric method and demonstrate that it can be directly measured on some clusters of defects embedded in a stoichiometric matrix. Results show that the value of the internal field grows in proximity of defects and vanishes far from them, which addresses the long-standing issue about its origin in Lithium Niobate crystal.
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| 6. |
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| 7. |
- Marzolla, M., et al.
(author)
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Open standards-based interoperability of job submission and management interfaces across the grid middleware platforms gLite and UNICORE
- 2007
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In: Proceedings - e-Science 2007, 3rd IEEE International Conference on e-Science and Grid Computing. - : IEEE Computer Society. - 0769530648 - 9780769530642 ; , s. 592-599
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Conference paper (peer-reviewed)abstract
- In a distributed Grid environment with ambitious service demands the job submission and management interfaces provide functionality of major importance. Emerging e-Science and Grid infrastructures such as EGEE and DEISA rely on highly available services that are capable of managing scientific jobs. It is the adoption of emerging open standard interfaces which allows the distribution of Grid resources in such a way that their actual service implementation or Grid technologies are not isolated from each other, especially when these resources are deployed in different e-Science infrastructures that consist of different types of computational resources. This paper motivates the interoperability of these infrastructures and discusses solutions. We describe the adoption of various open standards that recently emerged from the Open Grid Forum (OGF) in the field of job submission and management by well-known Grid technologies, respectively gLite and UNICORE. This has a fundamental impact on the interoperability between these technologies and thus within the next generation e-Science infrastructures that rely on these technologies.
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| 8. |
- Riedel, M., et al.
(author)
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Improving e-Science with Interoperability of the e-Infrastructures EGEE and DEISA
- 2008
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In: MIPRO 2008 - 31st International Convention Proceedings. - 9789532330366 ; , s. 225-231
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Conference paper (peer-reviewed)abstract
- In the last couple of years, many e-Science infrastructures have begun to offer production services to e- Scientists with an increasing number of applications that require access to different kinds of computational resources. Within Europe two rather different multi-national e-Science infrastructures evolved over time namely Distributed European Infrastructure for Supercomputing Applications (DEISA) and Enabling Grids for E-SciencE (EGEE). DEISA provides access to massively parallel systems such as supercomputers that are well suited for scientific applications that require many interactions between their typically high numbers of CPUs. EGEE on the other hand provides access to a world-wide Grid of university clusters and PC pools that are well suited for farming applications that require less or even no interactions between the distributed CPUs. While DEISA uses the HPC-driven Grid technology UNICORE, EGEE is based on the gLite Grid middleware optimized for farming jobs. Both have less adoption of open standards and therefore both systems are technically non-interoperable, which means that no e-Scientist can easily leverage the DEISA and EGEE infrastructure with one suitable client environment for scientific applications. This paper argues that future interoperability of such large e-Science infrastructures is required to improve e-Science in general and to increase the real scientific impact of world-wide Grids in particular. We discuss the interoperability achieved by the OMII-Europe project that fundamentally improved the interoperability between UNICORE and gLite by using open standards. We also outline one specific scientific scenario of the WISDOM initiative that actually benefits from the recently established interoperability.
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