Thermal fixing of holographic gratings in BaTiO_3

Abstract

Fixing of a holographic grating in a single BaTiO(3) crystal is studied in detail by means of a thermal process. Above T = 78 °C, oscillations of the diffracted intensity of the sample appear, which are related to the fixing process. Different methods to perform and optimize the fixing process are described. A fixed diffraction efficiency of ~25% was obtained. Self-enhanced as well as self-depleted diffraction from the fixed photorefractive gratings was observed.

Spectroscopic properties of photorefractiveBaTiO3double doped with cerium and rhodium

“…It should be pointed out that this angular variation is similar to that reported for Nd 3ϩ in this host. 19 For Ce 3ϩ located at a site with C 3v symmetry, the ground state 2 F 5/2 (Jϭ 5 2 ) splits into three Kramers's doublets. The spin Hamiltonian in Cartesian form for a system with effective electron spin Sϭ 1 2 is given by…”

“…Among these techniques are thermal fixing, electrical fixing, and two-photon or sensitized recording. Recently, both thermal fixing [3][4][5] and electrical fixing 6,7 have been demonstrated in nominally undoped BaTiO 3 crystals. The only report of sensitized recording in BaTiO 3 was that by Buse, Holtmann, and Krätzig 8 who demonstrated short-lived sensitization involving two defect species in a nominally undoped sample.…”

Multidimensional tomographic imaging using volume holography

“…However, the degeneracy derivation is straightforward. It results also in a quadratic equation for of the form (58) where (59) (60) (61) The spatial coordinates of the degeneracy surface are given by (62) (63) (64) with computed from (58). A numerical example is given in Fig.…”

Theoretical study on lifetime of thermal-fixed volume holographic phase grating in photorefractive crystals

“…That is called thermal fixing by which the information stored in the electronic space-charge distribution is compensated at elevated temperatures in a nonphotoactive ionic-charge distribution. Since then, the fixing and developing grating processes of doped LiNbO 3 [4−10] and other photorefractive materials such as Sr 0.75 Ba 0.25 Nb 2 O 6 [11] , BaTiO [12] 3 , and KTa 1−x Nb x O 3 [13,14] have been extensively studied. The experimental results reveal that the lifetime of the holographic gratings stored in photorefractive crystals are prolonged by the thermal fixing [6,15] .…”