Papers by Keyword: Electro-Optic Effect

Abstract: The relation between the dielectric tunability and the electro-optic (EO) effect of barium strontium titanate (Ba_0.5Sr_0.5TiO₃) thin film was discussed. The tunability of dielectric permittivity calculated from the complex admittance with planer electrodes reached to 53.1%, and the tunability of birefringence by EO effect was 0.6%. The birefringence change from EO effect was much lower than the tunability of dielectric permittivity. The materials with high tunability do not always exhibit high EO effect. This is concluded to arise due to the ionic mass in the EO materials.

Abstract: Thermal poling could make centrosymmetric fused silica optical fibers generate second-order nonlinearity effect and linear electooptic effect. In order to investigate the influence of thermal poling parameters on linear electooptic effect, a real-time test system, which mainly consists of an all polarization maintaining fiber Mach-Zehnder interferometer, has been utilized to monitor the whole thermal poling process in fibers. The processing parameters in thermal poling, such as applied poling voltage, poling duration and temperature, have been measured in real time. Based on those measurements, their influence on the linear electrooptic effect has been discussed. Experiment results show that the linear electrooptic coefficient would increase when a stronger electric field is applied on fibers. Considering the anti-high-voltage breakdown capability of fibers, a DC voltage from 3KV to 4KV is suitable for polarization in thermal poling. When using 3KV, the optimum poling duration is about 16 minutes and the best temperature for thermal poling is around 190°C. Keywords: electro-optic effect, poled fiber, thermal poling, real time test system, fiber optic interferometer

Abstract: La-modified 0.75Pb (Mg_1/3Nb_2/3)O₃-0.25PbTiO₃(PLMNT) electro-optic (EO) transparent ceramics were synthesized through a columbite precursor method. Excess PbO (10, 15 and 20 mol %) was added to study the effect on the transparency, electro-optic effect, and microstructures of PLMNT transparent ceramics. The phase structure of different samples can be identified as single perovskite structure with no second phase detected. The average grain size increased as the concentration of excess PbO increased from 10 mol% to 20 mol%. On the contrary, the transparency decreased with the increase of the concentration of excess PbO. When the concentration of excess PbO was 10 mol%, the transmittance was about 62% at 632.8nm. The EO coefficient was calculated through measuring the birefringence as a function of electric field. The EO coefficient increased with the increase of the concentration of excess PbO and the maximum EO coefficient reached 40.6×10^-16(m/V)² when the excess PbO was 20 mol%.

Abstract: Polymer-dispersed liquid crystals are one kind of important devices. With a He-Ne laser and a photoelectric detector, we measured the driving-voltage dependent and viewing-angle dependent transmission for a polymer-dispersed liquid crystal device. Our results showed that the polymer-dispersed liquid crystal device worked at the driving voltage of 4 V and the effective viewing angle of about 65 degree.

Abstract: The nonlinear optical susceptibility with inter-subband transitions between conduction band and valence band is theoretically calculated for CdSe/ZnS core-shell quantum dot (QD). Under the effective-mass approximation, the eigenenergy and wavefunction of electrons and holes have been calculated by solving stationary Schrödinger equation. The third-order nonlinear optical susceptibilities χ(3) of quadratic electro-optic effects (QEOE) have been also calculated in the case that spin-orbit splitting is considered.

Abstract: Lanthanum-modified lead zirconate titanate and lead zirconate titanate epitaxial films with (100) and (111) orientations were grown respectively on (100) and (111) niobium, lending conductivity to strontium titanate through chemical solution deposition. This study investigated changes in the ordinary and extraordinary refractive index
no and
ne induced in these films by an electric field using the prism-coupling method. In the (100) epitaxial PZT 30/70 film, anisotropic electro-optic effects arise from the Pockels effect. The isotropic electro-optic effect, which is
no =
ne , was achieved on (100) epitaxial PLZT 8/65/35 and PZT 70/30 films.