Bismuth Silicate Crystal Research Articles

Concentration of radiation displacement defects in BSO and BGO crystals irradiated by electrons or neutrons

Abstract This work is devoted to the calculation of the concentration of radiation displacement defects (RDD) in bismuth germanate and bismuth silicate crystals as a function of particle energy (electrons and neutrons). Energy dependencies of RDD concentrations are discussed in comparison with results for other complex oxide crystals. The obtained results show that for the case of electron irradiation the radiation hardness of BSO and BGO should be similar to other oxide crystals, but for neutrons is drastically smaller. Additionally, for the neutron irradiation, the efficiency of the production of defects in the oxide sublattice is drastically smaller than for other oxide crystals.

Multiwave Interaction of Light in a Bismuth Silicon Oxide Crystal in an Applied Meander Electric Field

An analysis is made of photorefractive nonlinearity resulting from the interaction between the charge gratings formed in a bismuth silicate crystal in an applied meander electric field under illumination by a strong reference and two signal light beams. It is shown that the nonlinear cross interaction between the primary holographic gratings recorded in the crystal should be taken into account where the intensities of the reference and signal light beams differ from one another in magnitude (less than 300 times).

Polarization-independent modulation of light in gyrotropic cubic crystals

Polarization-independent modulation of light in gyrotropic cubic crystals is investigated in the Bragg and intermediate diffraction regimes. It is found that, for crystals with considerable specific rotation, the photoelastic anisotropy is suppressed by the circular anisotropy and the observed diffraction efficiency depends weakly on the polarization azimuth of the incident light. Good agreement is obtained between modulation parameters calculated theoretically on the basis of the coupled wave theory and experimental results for a bismuth silicate crystal in the intermediate diffraction regime.

Effect of Chemical Polishing on the Photoconductivity of Bi12SiO20

After chemical polishing, the spectral response of bismuth silicate crystals shows a minimum at 0.41–0.43 μm, where photosensitivity is comparable to that in the red spectral region (0.6–0.63 μm).

Photorefractive gratings in sillenite crystals in a square-wave field

The space-charge-field harmonics in the refractive-index grating generated in a bismuth silicate crystal to which a square-wave external electric field is applied were examined theoretically and experimentally at high interference-pattern contrasts. The model taking into account three spatial harmonics ensures good agreement with experimental data for the fundamental- and second-harmonic gratings. By fitting the experimental data with theoretical curves, the acceptor concentration and the product of the carrier mobility and recombination time in the crystal were evaluated.

Nonlinearity of the photorefractive response upon two-beam interaction in a bismuth silicon oxide crystal in an alternating electric field

Nonlinearity of the photorefractive response is studied experimentally and theoretically upon two-beam interaction of light waves in a bismuth silicate crystal placed in an external meander electric field. The experimental data are shown to be in good agreement with a model, taking into account the influence of the second harmonic of the space-charge field on a photorefractive grating. The concentration of acceptors in a crystal and a product of the mobility of charge carriers by their recombination time are estimated from a comparison of the experimental and calculated data.

Periodic breakdown of a gas layer in the metal-gaseous dielectric-insulating semiconductor-metal structure under stationary illumination conditions

The size and location of the area of gas breakdown at the surface of an M(GD)SM structure based on a bismuth silicate crystal was studied under uniform illumination conditions. The amount of energy absorbed in the crystal that leads to breakdown of the gas layer is determined.

Nonunidirectional two-beam interaction in photorefractive bismuth silicate in an alternating electric field

The effective nonunidirectional energy exchange between like-polarized light beams is investigated experimentally on a photorefractive grating formed by diffusion drift in a bismuth silicate crystal placed in an alternating external electric field.

Directionally sensitive photorefractive interferometric line receiver for ultrasound detection on rough surfaces

An adaptive heterodyne interferometer is configured as a line receiver using wave mixing in photorefractive bismuth silicate crystal. The line receiver is directionally most sensitive to ultrasound impinging normal to the line, and is significantly less sensitive to ultrasound impinging in other directions. Such a system is attractive in situations where the ultrasonic scatter from a specific direction is to be selectively pulled out in the presence of scatter from other “noise” sources. It is also demonstrated that the line probe system can be used to bridge the sensitivity gap that optical detection thus far has suffered vis-à-vis piezoelectric detection.

Generation of spatial subharmonics of a photorefractive grating in bismuth silicate crystals in an alternating electric field

We investigate the polarization and electrical properties of additional light beams associated with the generation of the spatial subharmonic K/2 of a fundamental photorefractive grating with vector K parallel to the \([\bar 110]\) axis when a sample of the crystal bismuth silicate doped with cadmium is simultaneously subjected to an external AC electric field and illuminated by light at a wavelength of 633 nm.

Polarization effects associated with two-wave interaction in bismuth titanate and bismuth silicate crystals

Polarization effects associated with two-wave interaction in Bi12TiO20 and Bi12SiO20 crystals are investigated. The experimental data are subjected to the required theoretical analysis. A new procedure is proposed for determining the density of acceptor centers (NA) in photorefractive crystals. The values of NA obtained by this procedure are in good agreement with published data.

Light scattering in bismuth silicate: matching of experimental results

The scattering pattern of a coherent light beam incident perpendicularly on a bismuth silicate crystal in the presence of an applied electric field is investigated. A theoretical model is shown to give good agreement with the measurements provided the piezoelectric and photoelastic effects are incorporated into the usual coupled wave equations.

Optical nonreciprocity of counterpropagating light waves under Bragg diffraction conditions in gyrotropic cubic crystals

The coupled waves method is used in a calculation of the phase and amplitude nonreciprocity of counterpropagating light waves in the case of the acousto-optical interaction in gyrotropic cubic crystals. The dependences of the phase and amplitude nonreciprocities on the state of polarisation of light and on the gyrotropy parameter are determined for the Bragg diffraction by a shear ultrasonic wave. Numerical calculations are reported for a bismuth silicate (Bi12SiO20) crystal in the absence and the presence of the acousto-optical diffraction feedback.

Multiple forward phase conjugation in a photorefractive bismuth silicate crystal

The geometrical configuration in which two pump beams and one non coplanar signal beam are incident upon the same side of a bismuth silicate crystal is investigated. It is shown that a strong interaction giving rise to a multiplicity of output beams (three of them phase conjugate) may be obtained when the pump beams are detuned in the opposite directions by the same amount. The phase conjugate images obtained are analysed.

Investigation of the processes of anisotropic recording of optical data in bismuth silicate crystals

An analysis is made of the possibility of functional spatial conversion of optical signals recorded anisotropically in bismuth silicate crystals. The results are reported of a study of the spatial spectra of recorded images. These images are obtained as a result of the anisotropy of the transverse electrooptic effect in the plane of the wavefront of the readout radiation.