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The research and achievements of high performance polarizer coatings by many scholars around the world are reviewed, including the spectral properties, laser damage threshold and stress control. For the performance requirements of polarizer coatings in China Shenguang series facilities, it describes the investigation of spectral properties, laser damage threshold, and figure accuracy of the polarizer coatings based on electron beam depolarization by Shanghai Institute of Opitcs and Fine Mechanics of the Chinese Academy of Sciences(SIOM). Much work and achievements on design, preparation and past-treatment of the coating are given. On the basis of the research achievements, high performance thin films polarizer with low defect density and low stress have obtained. The Brewster angle thin film polarizer developed by our team has participated in the International Laser Damage Competition held on the SPIE 2012 Laser Damage & SPIE 2013 Laser Damage Symposium. The p-polarized LIDT(Laser Induced Damage Threshold) as well as the average of p-polarized and s-polarized LIDT achieves the best results. The stress-induced crazing of large aperture polarizer coating is also solved, by which the manufacturing of large aperture polarizer is implemented in China, showing the spectral properties of TP>98%, RS>99% and the flux property of 17 J/cm2(9 ns). Now, the prepared large aperture polarizer has supported the stable operation of ShenguangII-UP laser facility. ? 2016, Science Press. All right reserved.

In consideration of the development trends of backlights,a global dimming algorithm for side-lit backlights was proposed to solve the problems of Liquid Crystal Devices(LCDs) in low contrast ratio and high power consumption.The backlight dimming level was decided by the average luminance and the difference between the average and max grayscales of all subpixels.Then,the S-shaped function was involved to improve the static contrast ratio,by which the pixels with the grayscales more than the turning point of the curve could be become brighter and those less than the turning point could become darker,so that the static contrast ratio was improved efficiently.The algorithm was simulated and a prototype was developed to evaluate the effects of the dimming algorithm.Experimental results indicate that the power consumption of the LCD with the global dimming heavily depends on what to be displayed on the images.For 40 different kinds of images,the average power has reduced by 9.39% and the static contrast ratio improved by 124.7%.The side-lit backlights performing the proposed global dimming algorithm have the advantages of low-cost,small thickness,low power consumption and high constrast ratio.

To reveal the error propagation rules of camera geometric specification in stereoscopic mapping more accurately,the relationship between the mapping accuracy and specification difference parameters of dual-linear-array CCD camera is studied.Aiming at the characteristic of dual-linear-array stereoscopic mapping,effects of the geometric specification difference parameters on mapping positioning are analyzed.Based on the space forward intersection formula,the positioning accuracy(PA) model is established,and then the variations of PA with the difference between calibration errors of interior orientation elements are presented.The results show that the effect of the difference between principal point x errors on PA is obvious,and the PA rapidly decreases by 60% when the difference change increases to 2.5 μm from 1 μm.In addition,the effect of the difference between focus length f errors on PA can be almost neglected.The model and relevant conclusions have important guiding meaning for the optimization design and quantification of dual-linear-array CCD camera specification.

We report the generation of 207-fs pulses with 1.2 mW average power at 1036 nm directly from a passively mode-locked Yb-doped fibre laser with a nonlinear optical loop mirror for mode-locking and pairs of diffraction gratings for intracavity dispersion compensation. These results imply a 4-fold reduction in pulse duration over previously reported figure-of-eight cavity passively mode-locked Yb-doped fibre lasers. Stable pulse trains are produced at the fundamental repetition rate of the resonator, 24.0 MHz. On the other hand, this laser offers a cleaner spectrum and greater stability and is completely self-starting.