FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2284959908> ?p ?o ?g. }

• W2284959908 abstract "Poly(N-vinylcarbazole)-based PR polymer composites were investigated focussing on the particular features required for a potential application of this relatively new class of materials as optical holographic storage media in mass data storage devices. The main objective of this work was to get a more detailed insight into and a better understanding of the dynamic recording, erasure and dark decay behavior of holograms in this type of PR polymer. By means of a simplified model calculation the general diffraction properties of a hologram in PR polymers in the presence of strong beam coupling were examined. It could be proven that hologram bending due to strong beam coupling does not notably affect the diffraction properties of a holographic grating in organic PR devices within the range of the externally applied field experimentally possible. The dependence of the steady-state and the dynamic PR performance on the glass-transition temperature as well as on the doping level of electro-optic chromophores was investigated. The reduced temperature, which is the glass-transition temperature relative to the ambient temperature, was identified as a factor of outstanding importance. A steady-state performance optimum as a function of the reduced temperature was observed in materials containing large amount of chromophore. The hologram build up speed was found to be limited by the orientational mobility of the electro-optic chromophores for positive reduced temperatures. For negative reduced temperatures the dynamics of the space-charge field was identified as the rate-limiting step. The chromophore doping level only plays a role at positive reduced temperatures. Considering the influence of the sensitizer concentration on the steady-state and the dynamic PR behavior, strong indication was found that the active PR trap manifold consists of conformational traps on the one hand and of coulombic traps formed by charged sensitizers on the other. The first exist ab initio while the latter are formed during the grating recording process and add to the conformational traps. There is strong indication that the hologram build-up dynamics for typical sensitizer concentration is limited by the charge carrier mobility. The general erasure behavior of PR gratings was investigated in detail. For the dependence of the PR grating erasure on the reduced temperature, a relationship similar to the recording dynamics was found. In all cases, a strong correlation between the erasure dynamics of a hologram and its corresponding recording time was observed. The grating erasure process was found to slow down as a function of increasing recording time. For positive reduced temperatures this can be attributed to a viscous flow of the polymer matrix, whereas optical activation of trapping sites could be identified to cause this effect at negative reduced temperatures. The possible nature of the optically activated traps is discussed. It could be shown that an optimum reduced temperature must be anticipated for a potential application of the investigated materials in holographic multiplexing. Doping the materials with large amounts of extrinsic deep traps yielded a complicated erasure behavior. Applying short recording times and low light intensities, a further increase of the hologram strength was observed during the initial erasure process. A phenomenological mechanistic picture of the recording and the erasure process of a hologram in a material showing trap controlled charge transport is proposed, which can qualitatively explain the experimental observations. The dark decay of holograms was investigated in detail taking into account different glass-transition temperatures as well as extrinsic trap doping. Within the range of reduced temperatures investigated, the dark decay was found to be governed by the decay of the PR space-charge field. The phase shift of the PR grating turned out to be a crucial parameter yielding faster dark decay for smaller PR phase shifts. Eventually, holographic multiplexing in the investigated type of materials is demonstrated by means of peristrophic multiplexing experiments. Therefore an expanded numerical formalism for a multiplexing exposure schedule was to be devised, which accounts for the complicated dynamic behavior. In conclusion, the investigated type of holographic storage medium appears inapplicable for holographic mass data storage devices. This is mainly due to the complicated and unfavorable dynamic behavior, which appears to be an inherent feature of the investigated type of material, or possibly even the entire class of materials. However, this class of holographic storage materials may find application in any kind of volatile holographic storage like, among others, associative memories, buffer holograms, or time gated holographic imaging." @default.
• W2284959908 created "2016-06-24" @default.
• W2284959908 creator A5062898418 @default.
• W2284959908 date "2003-01-01" @default.
• W2284959908 modified "2023-09-23" @default.
• W2284959908 title "Basic Investigations on PVK-based Photorefractive Polymers Focussing on their Applicability as Mass Data Storage Media" @default.
• W2284959908 hasPublicationYear "2003" @default.
• W2284959908 type Work @default.
• W2284959908 sameAs 2284959908 @default.
• W2284959908 citedByCount "0" @default.
• W2284959908 crossrefType "dissertation" @default.
• W2284959908 hasAuthorship W2284959908A5062898418 @default.
• W2284959908 hasConcept C120665830 @default.
• W2284959908 hasConcept C121332964 @default.
• W2284959908 hasConcept C122865956 @default.
• W2284959908 hasConcept C128717455 @default.
• W2284959908 hasConcept C159467904 @default.
• W2284959908 hasConcept C159985019 @default.
• W2284959908 hasConcept C178790620 @default.
• W2284959908 hasConcept C18355248 @default.
• W2284959908 hasConcept C185592680 @default.
• W2284959908 hasConcept C187590223 @default.
• W2284959908 hasConcept C192468462 @default.
• W2284959908 hasConcept C192562407 @default.
• W2284959908 hasConcept C199360897 @default.
• W2284959908 hasConcept C207114421 @default.
• W2284959908 hasConcept C2777813233 @default.
• W2284959908 hasConcept C2778790127 @default.
• W2284959908 hasConcept C41008148 @default.
• W2284959908 hasConcept C49040817 @default.
• W2284959908 hasConcept C521977710 @default.
• W2284959908 hasConcept C57863236 @default.
• W2284959908 hasConcept C63131636 @default.
• W2284959908 hasConceptScore W2284959908C120665830 @default.
• W2284959908 hasConceptScore W2284959908C121332964 @default.
• W2284959908 hasConceptScore W2284959908C122865956 @default.
• W2284959908 hasConceptScore W2284959908C128717455 @default.
• W2284959908 hasConceptScore W2284959908C159467904 @default.
• W2284959908 hasConceptScore W2284959908C159985019 @default.
• W2284959908 hasConceptScore W2284959908C178790620 @default.
• W2284959908 hasConceptScore W2284959908C18355248 @default.
• W2284959908 hasConceptScore W2284959908C185592680 @default.
• W2284959908 hasConceptScore W2284959908C187590223 @default.
• W2284959908 hasConceptScore W2284959908C192468462 @default.
• W2284959908 hasConceptScore W2284959908C192562407 @default.
• W2284959908 hasConceptScore W2284959908C199360897 @default.
• W2284959908 hasConceptScore W2284959908C207114421 @default.
• W2284959908 hasConceptScore W2284959908C2777813233 @default.
• W2284959908 hasConceptScore W2284959908C2778790127 @default.
• W2284959908 hasConceptScore W2284959908C41008148 @default.
• W2284959908 hasConceptScore W2284959908C49040817 @default.
• W2284959908 hasConceptScore W2284959908C521977710 @default.
• W2284959908 hasConceptScore W2284959908C57863236 @default.
• W2284959908 hasConceptScore W2284959908C63131636 @default.
• W2284959908 hasLocation W22849599081 @default.
• W2284959908 hasOpenAccess W2284959908 @default.
• W2284959908 hasPrimaryLocation W22849599081 @default.
• W2284959908 hasRelatedWork W1545433677 @default.
• W2284959908 hasRelatedWork W1967258624 @default.
• W2284959908 hasRelatedWork W1986432054 @default.
• W2284959908 hasRelatedWork W1988371396 @default.
• W2284959908 hasRelatedWork W2021421279 @default.
• W2284959908 hasRelatedWork W2023889130 @default.
• W2284959908 hasRelatedWork W2034872559 @default.
• W2284959908 hasRelatedWork W2044437719 @default.
• W2284959908 hasRelatedWork W2044947681 @default.
• W2284959908 hasRelatedWork W2051778328 @default.
• W2284959908 hasRelatedWork W2053687274 @default.
• W2284959908 hasRelatedWork W2059680622 @default.
• W2284959908 hasRelatedWork W2065628964 @default.
• W2284959908 hasRelatedWork W2065660919 @default.
• W2284959908 hasRelatedWork W2091496531 @default.
• W2284959908 hasRelatedWork W2114894937 @default.
• W2284959908 hasRelatedWork W2945042383 @default.
• W2284959908 hasRelatedWork W2996214961 @default.
• W2284959908 hasRelatedWork W3088048743 @default.
• W2284959908 hasRelatedWork W2740558075 @default.
• W2284959908 isParatext "false" @default.
• W2284959908 isRetracted "false" @default.
• W2284959908 magId "2284959908" @default.
• W2284959908 workType "dissertation" @default.