Organic photorefractive materials

About: Organic photorefractive materials is a research topic. Over the lifetime, 697 publications have been published within this topic receiving 13041 citations.

Parametric study of photorefractive beam coupling in BaTiO3 at multiple wavelengths

Abstract: photorefractive two-beam coupling and energy transfer in BaTiO3 are studied at multiple wavelengths using He-Cd, He-Ne, and diode lasers. The photorefractive signal beam gain is measured as a function of the pump beam intensity, beam ratio intensity, spatial frequency of the grating, and angle between the grating vector and c axis of the crystal. The exponential gain coefficient is calculated from signal beam gain, and its dependence on the same parameters is studied. The dependence of the signal beam gain and exponential gain coefficient on spatial frequency are also evaluated theoretically and found to be in good agreement with the experimental data. Also, the signal beam gain is studied as a function of wavelength, and a very high value is obtained at 441.6 nm. Figure-of-merit parameters such as the maximum change in the refractive index, the space charge field at saturation, the trap density of the charge carriers, and the photorefractive sensitivity of the crystal are calculated from the experimental data. since the absorption in BaTiO3 varies strongly with wavelength, its influence has been included in the calculations of the figure-of-merit parameters. The results are discussed in the light of the present understanding of photorefractive phenomena in crystals.

Photoinduced charge transfer processes in photorefractive CdTE:Ge

Abstract: Charge redistribution between two different photorefractive centers in CdTe:Ge allows for enhancement of two-beam coupling at 1.064 µm and 1.32 µm by the additional illumination of the sample. The gain factor reached at 1.064 µm without external electric field is only 20% smaller than the theoretical limit for CdTe. The "net" gain is obtained at 1.064 µm as well as at 1.32 µm and 1.3 times amplification of the signal wave is achieved at 1.06 µm with no applied field.

Polarization interferometry measurement of the Pockels coefficient in a chiral Bi/sub 12/SiO/sub 20/ single crystal

Abstract: Single beam polarization interferometry was introduced to measure the Pockels coefficients in a BSO single crystal. The linear superposition principle of the induced birefringence and the optical activity was employed in the analysis of the Pockels effect measurement.

Photorefractive optical damage in protonated LiNbO3 waveguides

Abstract: The photorefractive optical damage in annealed proton-exchanged LiNbO3 planar waveguides is studied The pfotorefractive thresholds for the wavelengths 5145 and 6471 nm are determined Also, the light-induced refractive index change in a wide range of powers is determined An interesting and unexpected photorefractive behaviour of the samples in q-state (metastable at room temperature) and s-state (steady-state) is described An analysis of the light self action in s-type waveguides is performed and used for estimating the waveguide conductivity