Real-time holographic interferometry using photorefractive sillenite crystals with phase-stepping technique

This work presents a holographic interferometer that uses the photorefractive sillenite crystals in diffusive regimen whose configuration exhibits diffraction anisotropy for real-time holographic interferometry. The writing–reading process of holographic interferogram was done in real-time, connected with an interferogram-analysis method that uses the phase-stepping technique for quantitative measurement of changes on an object. The holographic interferograms from the analyzed surface were captured and they were used to calculate the phase map with four-frame technique. The unwrapping process used was the cellular-automata technique. We obtained quantitative results for some applications: measurements of micro-rotation of surfaces, punctual micro-displacements on an aluminum plate, stress on a dog's jaw, among others; adding new promising applications possibilities for basic research, dentistry and technological areas.     

光折变神经网络

本文阐述了几种神经网络模型和模式两分法中感知算法的一种光学执行过程。利用光折变介质动态全息术来存入和修正光学神经网络的加权矩阵。该系统可用以完成模式分类。还介绍了光折变晶体LiNbO₃的一些实验结果。     

Crystal diffraction grating in LiNbO3:Fe derived from interferometric volume holography

A 90° two-beam coupling configuration was used to store an image of an extended object in a 0.032 %wt iron-doped LiNbO₃ crystal. A volume hologram was thus generated, via the photorefractive effect, within the microstructure of the crystal. The time evolution of partial spatial erasure of the hologram under illumination was studied by capturing its reconstructed image on a digital camera and performing a two-dimensional inverse Fourier transform. This produced the refractive index grating created through interference of object and reference beams. The nature, intensity distribution and dimensions of the diffraction grating were derived in order to throw light upon the movement and mechanisms of charges, which create the index grating.     

非耗散介观含源电路的量子力学效应

本文对非耗散介观含源电路的量子力学效应进行了详细研究.导出了非耗散介观含源电路在压缩真空态下其电荷和电流的量子零点涨落,并得到了该电路在绝对零度时的量子噪音.     

Leaky photorefractive surface waves in Bi12TiO20 and Bi12SiO20 crystals

Consistent experimental and numerical simulation studies of photorefractive surface wave propagation in Bi₁₂TiO₂₀ and Bi₁₂SiO₂₀ crystals are presented. We induce the photorefractive surface wave with a Gaussian beam of small diameter and show that light leakage from the surface wave takes the form of multiple beam reflection from the crystal surface. The efficiency of surface wave excitation is proved to be much higher for the divergent Gaussian beam than for the convergent one.     

Output behavior based on writing occupancy in a photorefractive converter

In this paper, a one-dimensional image distribution is stored as modulation of birefringence in a BSO photorefractive crystal in an incoherent to coherent converter arrangement. The features of the read-out image under different write-in image magnifications of an input object are analyzed. In particular, characteristic parameters are introduced to assess the feasibility of an adequate recognition of the converted image. Experimental results under extinction configuration obtained by using intensity-normalized images are described.     

塞曼石墨炉原子吸收光谱法测定海水中的铬

利用石墨炉原子吸收光谱法测定海水中铬,塞曼效应扣除背景,选择抗坏血酸为基体改进剂.线性范围5-15μg/L,相关系数为0.9999,回收率为90%-102%,相对标准偏差为7.0%.     

Surface contouring by phase-shifting real-time holography using photorefractive sillenite crystals

This work proposes to obtain surface contouring by phase-shifting real-time holography using photorefractive sillenite crystals which provides the surface contouring from a change in phase of wavefront of the object illumination beam. The real-time holography using the photorefractive Bi₁₂SiO₂₀ crystal and the four-frame phase-shifting technique was used to obtain the phase map, this map was filtered by an anisotropic sin/cos filter and the unwrapping process used was the cellular-automata technique. We obtained experimental results of the surfaces of the large objects with real discontinuities, and these results agree with the dimensions of the object.