| 1. |
- De Angelis, M., et al.
(författare)
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Evaluation of the internal field in lithium niobate ferroelectric domains by an interferometric method
- 2004
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Ingår i: Applied physics letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 85:4, s. 2785-
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Tidskriftsartikel (refereegranskat)abstract
- We report on the evaluation of internal electric field of a ferroelectric engineered-domain in a LiNbO3 wafer crystal by detecting optical path length variation with a noninvasive interferometric inspection method. The lithium niobate wafer has been patterned and subjected to electric field poling to obtain two antiparallel ferroelectric domains separated by a single domain wall. The crystal has been mounted into one arm of a Mach-Zehnder-type interferometer to study the phase map and evaluate the effects of domain reversion by a digital holographic technique. Evaluation of the internal field and consequent variation of the electro-optical properties of the different domains is analyzed.
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| 2. |
- Grilli, Simonetta, et al.
(författare)
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Two-dimensional mapping of electro-optic phase retardation in lithium niobate crystals by digital holography
- 2005
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Ingår i: Optics letters. - 0146-9592. ; 30:13, s. 1671-1673
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate accurate two-dimensional mapping of the phase retardation induced by the electro-optic effect in lithium niobate crystals. Off-axis digital holography is used to investigate congruent z-cut crystals. The spatially resolved optical path difference is interferometrically measured while a linearly rising voltage ramp is applied to the crystal. This procedure provides information on the uniformity of crystals' electro-optic properties and offers the ability to detect the presence of defects that is of fundamental importance for reliable processing of photonic devices.
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| 3. |
- Paturzo, M., et al.
(författare)
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Investigation of electric internal field in congruent LiNbO3 by electro-optic effect
- 2004
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Ingår i: Applied physics letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 85, s. 5652-5654
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the effect of the defect-induced internal field on the electro-optic behavior of z-cut congruent lithium niobate crystals. We measure, by a spatially resolved interferometric technique, the phase retardation due to an external applied voltage occurring in two regions with opposite ferroelectric polarization. When measurements are performed just after electrical poling, the two opposite domains show a different electro-optic behavior. We interpret this as due to an elastic component of the internal field. In fact, the asymmetric behavior disappears when the sample is thermally annealed, i.e., when the internal field vanishes
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| 4. |
- Paturzo, M., et al.
(författare)
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On the origin of internal field in lithium niobate crystals directly observed by digital holography
- 2005
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Ingår i: Optics express. - 1094-4087. ; 13:14, s. 5416-
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Tidskriftsartikel (refereegranskat)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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| 5. |
- Grilli, Simonetta, et al.
(författare)
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Double-face and submicron two-dimensional domain patterning in congruent lithium niobate
- 2006
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Ingår i: IEEE photonics technology letters. - 1041-1135. ; 18, s. 541-
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Grilli, Simonettta, et al.
(författare)
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In-situ visualization, monitoring and analysis of electric field domain reversal process in ferroelectric crystals by digital holography
- 2004
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Ingår i: Optics express. - 1094-4087. ; 12:9, s. 1832-1842
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Tidskriftsartikel (refereegranskat)abstract
- In-situ monitoring of domain reversal in congruent lithium niobate by a digital holographic technique is described. While the ferroelectric polarization is reversed by electric field poling, the two-dimensional distribution of the phase shift, due mainly to the linear electro-optic and piezoelectric effects, is measured and visualized. Digital holography is used to reconstruct both amplitude and phase of the wavefield transmitted by the sample to reveal the phase shift induced by adjacent reversed domains during the poling. The resulting movies of both amplitude and phase maps, for in-situ visualization of domain pattern formation, are shown. The possibility of using the technique as tool for monitoring in real-time the periodic poling of patterned samples is discussed.
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