Volume hologram recording and charge transfer process in Bi12SiO20 and Bi12GeO20

Abstract

Bi12SiO20 and Bi12GeO20 are photoconductive and electro-optic crystals in which hologram recording is performed using the photorefractive effect; their sensitivity and optical quality are comparable with the high-resolution photographic plate. Hologram formation and erasure are analyzed in terms of a simple two-level charge transfer model. The photocarrier’s displacement length, comparable with fringe spacing and the nearly unity quantum efficiency, allows the attainment of the ultimate photosensitivity. The trapping centers concentration being much smaller than the absorption centers concentration, the saturation recording time and diffraction efficiency are found limited only by the trap-filling mechanism.

Orientation and Temperature Dependence of Piezoelectric Properties for Sillenite-Type Bi12TiO20 and Bi12SiO20 Single Crystals

“…The structure of sillenite-type crystals was first determined by Sillen [3] and later refined by Efendiev and Wiehl [4,5]. Due to the space group, these crystals present a number of remarkable properties, such as piezoelectric, electro-optic, elastic-optic and photoconductive properties, which have potential applications in spatial light modulators, acoustic delay lines, for hologram recording and phase conjugation [6][7][8][9][10][11][12]. Of particular importance is that these crystals are piezoelectric semiconductors with large piezoelectric constant (d 14 ~ 40 pC/N), large electromechanical coupling factor (˃30%), large band gap energy (3.15-3.25 eV) and fast response time [6,13], in addition, there is no ferroelectric and pyroelectric properties, related to the 23 point group.…”

Electron diffraction study of the sillenites Bi12SiO20, Bi25FeO39 and Bi25InO39: Evidence of short-range ordering of oxygen-vacancies in the trivalent sillenites

“…In the present work, an electron diffraction study of sillenite crystals was undertaken to investigate the disorder of the trivalent compounds. Our results show that the ED patterns of Bi 12 SiO 20 . The measurements prove a deviation of the trivalent sillenites from the ideal sillenite structure and corroborate the hypothesis from previous optical studies.…”

“…The sillenite structure is exclusive to bismuth oxygen compounds and is described by the meta-stable parent-compound γ -Bi 2 O 3 which houses the Bi 3+ ion in the center of the tetrahedron. 33 In the sillenites, Bi 12 SiO 20 and Bi 12 GeO 20 , the sillenite structure is stabilized by fully replacing the Bi 3+ ion by small tetravalent ions. These two tetravalent sillenites have the simplest structure of all sillenites and their structure will be referred to as the ideal structure.…”

“…11,12 The last decade has witnessed an increase in the study of these compounds for photocatalysis and novel applications. [13][14][15][16][17] The physical and electronic structure of sillenites remains important and continues to motivate synthesis, [18][19][20][21][22] optical, [23][24][25] first principles, [26][27][28] dielectric, 29 magnetism, 30 and high-pressure studies.…”

L'effet photoréfractif

“…Il fut proposé dès 1969 pour décrire l'effet photoréfractif [3]. Il a d'abord été résolu pour des cas particuliers [9][10][11][12][13][14][15][16][17][18] (longueurs de diffusion très petites ou très grandes devant la période de la variation d'intensité lumineuse). Le développement le plus utile fut donné par Kukhtarev et col. en 1979 [19,20].…”