Search results for "Angular variation"

showing 2 items of 2 documents

Zero axial irradiance by annular screens with angular variation

1992

For optical alignment, it may be convenient to use a three-dimensional diffraction pattern with zero irradiance along the optical axis. This pattern is created here by using annular screens in the form of a phase daisy, a daisy flower, or a pie, with an even number of slices of an equal central angle and with every other slice with a phase retardation of 180 degrees . We recognize this form of angular variation as a particular solution of a wider set of functions that are able to produce zero axial irradiance.

PhysicsDiffractionOptical alignmentCentral anglebusiness.industryMaterials Science (miscellaneous)Zero (complex analysis)IrradiancePhase (waves)Industrial and Manufacturing EngineeringPtychographyOptical axisAngular variationOpticsFresnel numberBusiness and International ManagementbusinessFresnel diffractionApplied Optics
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ESR of Nd3+ in BaTiO3

1990

Afin d'identifier les defauts responsables de l'effet photo-refractif dans BaTiO 3 , on etudie ces cristaux. Les echantillons contiennent generalement divers etats de charge et des associations de Fe, Cr, ainsi que des trous de O − induits par le rayonnement. On trouve un nouveau centre qui doit etre attribue a Nd 3+ . Dans la presente etude, l'echantillon utilise n'est pas dope, et on l'etudie dans la phase rhomboedrique a T∼77 K. Il apparait que Na est une impurete courante dans BaTiO 3 probablement incorporee avec le materiau de depart, BaCO 3

chemistry.chemical_classificationAngular variationchemistryMineralogyPhysical chemistryCondensed Matter PhysicsInorganic compoundElectronic Optical and Magnetic Materialsphysica status solidi (b)
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