晶体美丽有用, 构造和谐有序。光电功能晶体可实现光能和电能的相互转化, 在微电子、光电子、通信、航天及现代**技术等高科技领域占有重要地位。人类认识晶体, 源于天然矿物。从矿物晶体的发现到光电功能晶体的人工生长和应用经历了漫长的发展, 晶体种类、晶体质量、生长理论、生长技术以及应用等方面均取得了较大进展。本文简述了从矿物宝石到晶体学发展的历程, 介绍了压电晶体、电光晶体、激光晶体、非线性光学晶体和闪烁晶体等几类光电功能晶体发展历程及晶体生长研究的进展, 展望了未来光电功能晶体的发展趋势。

A Mach-Zehnder interferometer (MZI) based on two spherical structures is proposed and temperature and humidity are measured simultaneously. The device is fabricated by inserting two spherical structures into a single mode optical fiber (SMF). The results of the experiment indicate that the temperature sensitivities are 0.079 nm/oC and 0.090 nm/oC from 10 oC to 60 oC, respectively. When the humidity changes from 30% to 70%, the humidity sensitivities are 0.148 nm/%RH and 0.06 nm/%RH, respectively. Therefore, temperature and humidity are measured simultaneously by the sensitive matrix. The new structure is demonstrated to be a particularly useful approach to detect temperature and humidity.

An in-line Mach-Zehnder interferometer (MZI) for simultaneous measurement of temperature and refractive index (RI) is proposed and demonstrated. The sensor is composed of cleaved taper, single-mode fiber (SMF) and spherical structure. Using precision device to measure the position of waist, the cleaved taper structure is obtained by cutting the taper structure. The sensitivities of the temperature are 0.052 nm/℃ and 0.037 nm/℃ in the temperature range of 25—70 ℃, respectively. The RI sensitivities are -56.59 nm/RIU and -43.53 nm/RIU in the RI range of 1.335—1.38, respectively. This sensor has many advantages such as compact structure and good stability.

For the ghost in visual background extractor (ViBe) algorithm and the influence of dynamic background, an improved ViBe algorithm is proposed to extract moving object in this paper. The way of background acquisition during modeling is improved to eliminate the ghost. Detect the saliency of the pre-M-frame, and synthetic relatively real background. Modeling with the background can avoid the generation of ghost. The selection of thresholds in the model is improved to reduce the impact of the dynamic background. Adjust the thresholds adaptively according to the background com-plexity. In addition, find the inner contour of extracted object to fill, which makes the detected targets more complete. Experimental results show that the presented algorithm effectively removes ghosts and enhances anti-interference abil-ity. Compared with several existing methods, the presented algorithm has better performance.

In order to improve the super-resolution reconstruction effect of the single image, a novel multiple dictionaries learn-ing via support vector regression (SVR) and improved iterative back-projection (IBP) are proposed. To characterize the image structure, the low-frequency dictionary is constructed from the normalized brightness of low-frequency im-age patches in a discrete-cosine-transform (DCT) domain. Pixels determined by Gaussian weighting are added to the input vector to restore more high-frequency information when training the high-frequency image patch dictionary in the space domain. During post-processing, the improved IBP is employed to reduce regression errors each time. Ex-periment results show that the peak signal-to-noise ratio (PSNR)and structural similarity (SSIM) of the proposed method are enhanced by 1.6%—5.5% and 1.5%—13.1% compared with those of bicubic interpolation, and the pro-posed method visually outperforms several algorithms.

A single-mode-few-mode-thin-core-single-mode (SFTS) structure based optical fiber sensor is fabricated and experi-mentally studied. The sensing principle relies on the inter-modal interference. Since the core diameter of few-mode fi-ber (FMF) is larger than that of single-mode fiber (SMF), the FMF helps to allow more light to enter the cladding of thin-core fiber (TCF), which helps TCF to excite cladding modes. The interference between core and cladding modes in TCF occurs at the joint of lead-out SMF and TCF. Experimental results demonstrate a refractive index (RI) sensitiv-ity of .103.34 nm/RIU and a temperature sensitivity of 0.05 nm/℃. The proposed sensor not only can measure tem-perature, but also can measure RI. In addition, the proposed sensor is simple for without complicated fabrication proc-ess.

提出了一种自动选择最优路径的高精度的机器人归零新方法，制作了高精度视觉光电多指节机器人系统。该归零方法的基本原理是根据机器人的停放点相对于零位接近开关的位置自动选择最近的归零路径，以零位接近开关和编码器 Z信号共同判断最终零点。现场应用实验结果表明：项目组的视觉光电多指节机器人 1轴臂长 350 mm，可操作范围 220°；2轴臂长 250 mm，可操作范围 300°；3轴臂长 150 mm；4轴 360°自由转动。该机器人系统目前已成功应用于工件上下料和码垛作业中，系统运行稳定，点重复精度达 0.02 mm，除归零外的水平联动速度达到 5.2 m/s。采用本文的归零新方法，各轴归零时间均在 10 s内，归零误差均在 2个脉冲数以内。据我们所知，该方法国内、外未见报道，也未见实际应用案例。