Photorefractive Optical Image Transfer in Feedback Signal Communication

Abstract

We have measured the resistive transition of molecular beam epitaxy prepared Bi 2 Sr 2 CaCu 2 O 8+x thin films in the presence of perpendicular low magnetic fields H (0 Oe < H < 1100 Oe) for different values of the bias current density J (10 2 A cm −2 < J < 10 5 A cm −2 ). The experimental data show two distinct dissipative behaviours. In the low-current region (J < 10 3 A cm −2 ) the electrical resistivity ρ is independent on J , changing only with H , while in the high-current region (J > 10 4 A cm −2 ) ρ is independent of both the bias current and the magnetic field. The result is considered in terms of thermally activated flux flow-flux creep-steady flux flow crossovers. The role of the statistical distribution of the pinning energy in the vortex dynamics is discussed.

Generation of Multi Self-Pumped Phase-Conjugated Waves by Pulsed Laser

“…In the latter study, interactions were eliminated, such as scattering and interference, between two laser beams directed on opposite faces of a single photorefractive BaTiO 3 crystal using nanosecond-pulsed beams instead of continuous-wave beams. [6][7][8][9] However, it is necessary to develop more efficient methods for generating phaseconjugated images with more types of information, for further applications of optical information processing. In order to generate more SPPC beams with different types of information, some methods are considered: reducing the number of incident pulses, dividing one beam into some beams with different types of information, and increasing the number of incident beams.…”