Neutron physics with photorefractive materials

Autor(en)

Martin Fally, Christian Pruner, Romano Rupp, Gerhard Krexner

Abstrakt

When the subject of photorefractive effects began with the discovery of light- induced refractive-index inhomogeneities in lithium niobate, neutron optics had already been established for more than 20 years. Both of the fields have evolved independently from each other into important branches of sciences and industry. In 1990 those dynamic areas were linked by an experiment in which cold neutrons were diffracted from a grating created by a spatially inhomogeneous illumination of doped polymethylmethacrylate (PMMA). A typical holographic two-wave mixing setup was used to record a refractive-index pattern, a grating,in PMMA that was reconstructed not only with light, as usual, but also with neutrons. Evidently, the illumination induced refractive-index changes for both, light and neutrons! In analogy to light optics this phenomenon is called the photo-neutron-refractive effect. The chapter is organised as follows: Starting with a concise explanation of the relevant concepts in neutron optics, electrooptics and photorefraction, as well as diffraction phenomena, we introduce PMMA and the electrooptic crystal LiNbO3 as examples for photo-neutron-refractive materials. The main part is concerned with neutron diffraction experiments performed on deuterated PMMA (d-PMMA). It is shown that this type of experiments can be useful when studying the polymerisation process itself, when serving simply as a neutron-optical element, or when probing fundamental properties of the neutron. The latter is in particular true of electro neutron-optic LiNbO3, where the diffracted neutrons are inherently exposed to extremely high electric fields due to the light-induced charge transport. Corresponding experiments are presented and future perspectives of photo-neutron-refractive materials as well as their possible applications are discussed. Finally, atomic-resolution neutron holography is introduced and conducted experiments are presented.

Organisation(en)

Physik Funktioneller Materialien

Band

3

Seiten

321-353

Anzahl der Seiten

33

DOI

https://doi.org/10.1007/978-0-387-34728-8_12

Publikationsdatum

2007

ÖFOS 2012

103008 Experimentalphysik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/5b47fb6f-4ccc-48dd-850a-e7f08206974c