偏振光斯托克斯参量的高速实时测量技术

为了满足对高速变化的偏振态的测量,提出一种能够对偏振态实现高速测量的技术。阐述了利用1/4波片与起偏器测量偏振光的斯托克斯参量常规的原理和方法,根据高速测量的要求推导出了新的斯托克斯参量计算公式,并依据此公式设计了基于多通道偏振态高速测量的方案,设计了具体的方法并编写了控制与算法程序。测试表明,该系统的测量速度达到了每秒700次偏振态测量,测量速度主要由电子线路的性能决定,测得的结果稳定可靠实现了光纤传输偏振态的高速测量。

Structural, optical and electrical properties of ZnO films grown on c-plane sapphire and (100)gamma-LiAlO2 by pulse laser deposition

ZnO thin films were grown on single-crystal gamma-LiAlO2 (LAO) and sapphire (0001) substrate by pulsed laser deposition (PLD). The structural, optical and electrical properties of ZnO films were investigated. The results show that LAO is more suitable for fabricating ZnO films than sapphire substrate and the highest-quality ZnO film was attained on LAO at the substrate temperature of 550 degrees C. However, when the substrate temperature rises to 700 degrees C, lithium would diffuse from the substrate (LAO) into ZnO film which makes ZnO film on LAO becomes polycrystalline without preferred orientation, the stress in ZnO film increases dominantly and the resistivity of the film decreases exponentially. (c) 2005 Elsevier B.V. All rights reserved.

Structural, morphological and optical properties of ZnO thin films grown on gamma-LiAlO2 substrate by pulsed laser deposition

ZnO thin films were deposited on the substrates of (100) gamma-LiAlO2 at 400, 550 and 700 degrees C using pulsed laser deposition (PLD) with the fixed oxygen pressure of 20 Pa, respectively. When the substrate temperature is 400 degrees C, the grain size of the film is less than 1 mu m observed by Leitz microscope and measured by X-ray diffraction (XRD). As the substrate temperature increases to 550 degrees C, highly-preferred c-orientation and high-quality ZnO film can be attained. While the substrate temperature rises to 700 degrees C, more defects appears on the surface of film and the ZnO films become polycrystalline again possibly because more Li of the substrate diffused into the ZnO film at high substrate temperature. The photoluminescence (PL) spectra of ZnO films at room temperature show the blue emission peaks centered at 430 nm. We suggest that the blue emission corresponds to the electron transition from the level of interstitial Zn to the valence band. Meanwhile, the films grown on gamma-LiAlO2 (LAO) exhibit green emission centered at 540 nm, which seemed to be ascribed to excess zinc and/or oxygen vacancy in the ZnO films caused by diffusion of Li. from the substrates into the films during the deposition.

用PLD法在MgO（100）衬底十生长ZnO薄膜的结构和光学特性

用脉冲激光沉积法在MgO（100）衬底上沉积了ZnO薄膜．衬底温度分别为400℃、550℃和700℃．利用X射线衍射（XRD）和光致发光谱（PL）对薄膜的结构和光学性能进行研究．x射线衍射的结果表明，在400℃和550℃下生长的ZnO薄膜具有高度c一轴择优取向．仉足当衬底温度升高到700℃时，薄膜由单一的择优取向变为有两个较强的择优取向．通过光致发光谱可以发现，在550℃下生长的ZnO薄膜具有强的紫外发射和窄的FWHM，并且紫外发光峰的强度与ZnO薄膜的结晶质量密切相关．

Al2O3衬底上生长ZnO薄膜的结构和光学特性

用脉冲激光沉积法在Al2O3（0001）衬底上沉积了ZnO薄膜。衬底温度分别为300℃、400℃、500℃、600℃和700℃。利用X射线衍射（XRD）和光致发光谱（PL）对薄膜的结构和光学性能进行研究。X射线衍射的结果表明在不同温度下生长的ZnO薄膜均具有高度c轴择优取向，衬底温度400℃时，膜的应力较小质量较高。ZnO薄膜有很强的紫外发光峰，紫外发光峰的强度与衬底温度密切相关，并发现当衬底温度从300℃增到400℃时，紫外发射峰出现6nm的蓝移。

Raman spectroscopic investigation of pure and ytterbium-doped rare earth silicate crystals

Raman spectroscopy was used to study the molecular structure of a series of selected rare earth (RE) silicate crystals including Y2SiO5 (YSO), LU2SiO5 (LSO), (Lu0.5Y0.5)(2)SiO5 (LYSO) and their ytterbium-doped samples. Raman spectra show resolved bands below 500 cm(-1) region assigned to the modes of SiO4 and oxygen vibrations. Multiple bands indicate the nonequivalence of the RE-O bonds and the lifting of the degeneracy of the RE ion vibration. Low intensity bands below 500 cm(-1) are an indication of impurities. The (SiO4)(4-) tetrahedra are characterized by bands near 200 cm(-1) which show a separation of the components of nu(4) and nu(2), in the 500-700 cm(-1) region which are attributed to the distorting bending vibration and in the 880-1000 cm(-1) region which are attributed to the symmetric and antisymmetric stretching vibrational modes. The majority of the bands in the 300-610 cm(-1) region of Re2SiO5 were found to arise from vibrations involving both Si and RE ions, indicating that there is considerable mixing of Si displacements with Si-O bending modes and RE-0 stretching modes. The Raman spectra of RE silicate crystals were analyzed in terms of the molecular structure of the crystals, which enabled separation of the bands attributed to distinct vibrational units. Copyright (C) 2007 John Wiley & Sons, Ltd.

Homoepitaxial growth of ZnO films via low-temperature liquid-phase epitaxy

Homoepitaxial ZnO films have been grown via liquid-phase epitaxy (LPE) on (000 1) oriented ZnO substrates. X-ray rocking curve revealed the high quality of the ZnO films with a FWHM of 40 arc sec. Films of thickness about 20 gm were gown in the temperature range 700-720 degrees C. The growth rate of ZnO films was estimated to be 0.3 mu m h(-1). Atomic force microscope analysis showed that the surface roughness of ZnO films was very low, which further confirmed the high crystallinity of ZnO films. (c) 2006 Elsevier B.V. All rights reserved.

Nonpolarizing beam splitter designed by frustrated total internal reflection inside a glass cube

A method for the design of an all-dielectric nonpolarizing prism beam splitter utilizing the principle of frustrated total internal reflection is reported. The nonpolarizing condition for a prism beam splitter is discussed, and some single layer design examples are elaborated. The concept can be applied to a wide range of wavelengths and arbitrary transmittance values, and with the help of a computer design program examples of 400-700 nm, T-p = T-p = 0.5 +/- 0.01, with incident angles of 45 degrees and 62 degrees are given. In addition, the sensitivity and application of the design are also discussed. (c) 2006 Optical Society of America.

Structure and UV emission of nanocrystal ZnO films by thermal oxidation of ZnS films

ZnO films prepared by the thermal oxidation of the ZnS films through thermal evaporation are reported. The as-deposited ZnS films have transformed to ZnO films completely at 400 degrees C. The 400-700 degrees C annealed films with a preferential c-axis (002) orientation have a hexagonal wurtzite structure. The band gap of ZnO films shifts towards longer wavelength with the increase of the annealing temperature. The relationship between the band gap energy of ZnO films and the grain size is discussed. The shift of the band gap energy can be ascribed to the quantum confinement effect in nanocrystal ZnO films. The photoluminescence spectra of ZnO films show a dominant ultraviolet emission and no deep level or trap state defect emission in the green region. It confirms the absence of interstitial zinc or oxygen vacancies in ZnO films. These results indicate that ZnO film prepared by this simple thermal oxidation method is a promising candidate for optoelectronic devices and UV laser. (c) 2005 Elsevier BN. All rights reserved.

Influence of different post-treatments on the structure and optical properties of zinc oxide thin films

Zinc oxide (ZnO) films with c-oriented were grown on fused quartz glass substrates at room temperature using dc reactive magnetron sputtering. The as-grown films were annealed at 700 degrees C in air and bombarded by ion beam, respectively. The effects of post-treatments on the structural and optical properties of the ZnO films were investigated by X-ray diffraction (XRD), photoluminescence (PL), optical transmittance and absorption measurements. The XRD spectra indicate that the crystal quality of ZnO films has been improved by both the post-treatments. Compared with the as-grown sample, both annealed and bombarded samples exhibited blueshift in the UV emission peaks, and a strong green emission was found in the annealed ZnO film. In both optical transmittance and absorption spectra, a blueshift of the band-gap edge was observed in the bombarded film, while a redshift was observed in the annealed film. (c) 2004 Elsevier B.V. All rights reserved.

南亚热带森林植物生物量、生产力及能量利用效率研究

以南亚热带地带性植被季风常绿阔叶林、各种人工林、半自然林和灌草丛等群落为对象，在长达十余年的时间里研究了各群落的冠层结构、辐射能环境和生理生态特征等，在此基础上采用了有关的数字模型进行模拟，并用时空替代的方法将天然林和人工林结合起来分析了生态系统动态演替过程中的能量生态特征。该成果填补了世界上本地带植被生物量和生产力研究的空白，对能量生态学的定义、研究体系和研究历史有新的认识。此外，在生物量和生产力、叶面积指数、细根生物量、测树器等研究方法上有创新。发表专著1本，论文56篇，论文中有15篇发表国际刊物上，42篇发表在国内核心刊物上。论文发表后，被SCI收录2篇共5次，STP收录2篇、被BA和CA等国外文摘收录21篇次，被国内各类文摘收录50次，被国内学者引用700多次。研究成果达国际先进水平，某些方面达国际领先水平。

《中国双子叶木本植物叶的宏观结构》（英文版）

本书是一部区域性的系统记载植物叶形态的专著，对我国华南地区习见的96科、315属、700多种双子叶木本植物叶的宏观结构，包括：叶形、脉序：1-6级脉、脉岛、盲脉、叶缘脉等形态，逐一分布加以描叙，在各属内列有脉序特征为依据的分种检索表，每种除文字记载外，均附有显示叶形及各级脉序的照片两帧，以便于鉴定。所引用的标本均标明出处，以便查对。此外还附有每种植物的地理分布、习性、生境等资料。这样内容的书在我国尚属首次。目前国内外发表的叶片脉序论著都是专科专属的研究。本书研究记载范围广，资料性较强对研究现代双子叶植物分类系统有重要参考价值，对古植物学研究有很大帮助，对地质工作也有一定的实用意义。全书用英文撰写，更便于各国学者交流参考。