Light induced refractive index changes in PMMA films doped with styrene

Franke, H.; Festl, H. G.; Krätzig, E.

doi:10.1007/bf01458963

Cited by 21 publications

(1 citation statement)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this sense all materials are photorefractive, and observation of photorefractive effects depends on the optical intensity used and the transparency of the material. Light-induced polymerization [8], light-induced reorientation of polymers [9][10][11][12], and the Franz-Keldysh effect [13][14][15][16] are a few examples of photorefractive processes. However, the "photorefractive effect in electrooptical crystals" names a special process that is illustrated in Figure 4.1.…”

Section: Fundamentals Of Photorefractive Effectsmentioning

confidence: 99%

Photorefractive Effects in LiNbO3 and LiTaO3

Buse

Imbrock

Krätzig

et al.

Photorefractive Materials and Their Applications 2

View full text Add to dashboard Cite

Lithium niobate (LiNbO 3 ) and lithium tantalate (LiTaO 3 ) crystals have gained increasing interest during recent years because of their fascinating physical properties, such as piezoelectricity, ferroelectricity, pyroelectricity, birefringence, electrooptical, and nonlinear-optic effects. These properties have been successfully utilized for applications in various fields. Basic experiments on acoustic surface wave propagation, electrooptical modulation, optical wave guiding, second harmonic generation, and pyroelectric detection have been performed with these crystals.LiNbO 3 and its isomorphous compound LiTaO 3 are not found in nature. The first successful growth of large single crystals by the Czochralski technique was reported by Ballman [1]. A peculiarity results from the fact that the congruently melting composition (about 48.4 mol % Li 2 O) does not coincide with the stoichiometric one (50 mol % Li 2 O). The crystals have a perovskite-like structure with oxygen octahedra and are trigonal with only one structural phase transition (paraelectric-ferroelectric) at the Curie temperature T c of about 1150 • C for LiNbO 3 and about 610 • C for LiTaO 3 . The nonpolar high-temperature phase belongs to the space group R3c (point group 3m) and at T c the transition to the ferroelectric low-temperature phase of the space group R3c (point group 3m) occurs. At room temperature LiNbO 3 is negatively birefringent. The birefringence of LiTaO 3 is very small at room temperature and positive for the congruently melting composition. More information about growth and fundamental properties of LiNbO 3 can be found in [2,3]. 83

show abstract

Section: Fundamentals Of Photorefractive Effectsmentioning

confidence: 99%

Photorefractive Effects in LiNbO3 and LiTaO3

Buse

Imbrock

Krätzig

et al.

Photorefractive Materials and Their Applications 2

View full text Add to dashboard Cite

show abstract

Information Storage Materials, Optical

Kämpf¹,

Mergel²

2000

Kirk-Othmer Encyclopedia of Chemical Technology

View full text Add to dashboard Cite

In addition to the established magnetic mass storage media (floppy disk, hard disk, tape) optical mass storage media (CD‐ROM (compact disk‐read only memory), WORM (write once, read many times), EOD (erasable optical disk)) are increasingly used. Generally, magnetic and optical media do not compete, but complement each other due to their specific advantages. Progress in optical data storage technology is closely connected with the development of suitable materials. This article illustrates in detail the current state of the art and the ongoing development of materials for optical data storage. For the information layer of WORM disks, dyes with high ir absorption, low heat conductivity, and good solubility are required. Besides polymethine dyes, biaxially substituted silicon–naphthalocyanines are used; also combinations of metal complexes are employed. The magneto‐optical materials for EOD‐disks in MOR (magneto‐optical recording) technique are primarily ferrimagnetic ternary amorphous alloys of rare‐earth (RE) and transition‐metals (TM) (GdTbFe, TbFeCo, DyFeCo). Ferrites with spinel‐ or garnet‐structure, eg, rare‐earth iron‐garnets (RIG), are commercially unimportant mainly due to their high deposition temperature. Co/Pt‐multilayers (MLs) exhibit interesting properties, but are still waiting for commercial introduction. Research concentrates on exchange‐coupled RE‐TM layers, which permit a direct overwrite procedure. Phase‐change materials for EOD‐disks in PCR (phase‐change recording) technique are primarily ternary alloys (eg, GeSbTe, InSbTe). Research focuses on materials with fast crystallization in parallel with high stability even at numerous write/read/erase cycles. As substrate materials for CD‐ROM disks, end group‐modified bisphenol A–polycarbonate (BPA‐PC) is employed exclusively. For WORM and EOD disks mainly BPA‐PC and sometimes glass is applied.

show abstract