2000年光学年报.pdf

复 旦 大 学 光科学与工程系 Department of Optical Science & Engineering Fudan University 2000 2000年报 Annual Report (Contents) 目录(Contents) 简介 (Preface) 2 我室名誉教授和顾问教授 (Honorary and advisory professors) 3 课题进展 (Progress in research projects) 4 在研课题和经费 (Projects and Budgets) 25 发表文章情况 (Publications) 32 参加国际、国内会议情况 (Scientific activities) 40 人员名单 (Faculty members) 45 访问学者和部分参观人员(Guest scientists & some visitors) 50 附录：发表文章首页 (First page of selected publications) 52 通讯地址(Postal address)：上海市复旦大学光科学与工程系，200433 (Department of Optical Science & Engineering, Fudan University, Shanghai 200433, China) 电话(Tel.)：86-21-65643791/65649001 网址(Web)：http://optics.fudan.edu.cn 电子信箱(E-mail)：mmlab@fudan.edu.cn 传真(Fax)：86-21-65641344 1 简 介 复旦大学激光物理和光学研究室是全国最早建立的光学专业之一。本学科 点前身是于1954年成立的、以周同庆教授（我国著名光谱学家，中科院学部委 员）为主任的光学教研室。教研室于1964年研制出He-Ne等多种气体激光器后， 积极开展各类激光器和相关元器件、激光技术和应用及光物理等研究工作，研 究队伍迅速扩大。1978年成立以章志鸣教授为主任的激光物理和光学研究室， 1981年批准成为光学硕士点。 1984年被批准为光学博士点，1988年批准为国家级重点学科，同年建立三 束材料改性国家重点联合实验室复旦分部。在1988年的光学学科点评估和1993 年的博士点评估中，本学科排列全国高校光学专业的第一，并于1990年荣获国 家科委和教委共同颁发的“全国高等学校科学研究先进集体”称号。1996年被 确立为“211工程”重点建设学科。2000年9月该学科点大部与陈良尧教授研究 组合并，成立光科学与工程系。 本系现有科研人员31人（具有博士学位20人），其中教授12名（含院士2 名），副教授14名，国家杰出青年科学基金获得者2名（1名为教育部长江特聘 教授）和年轻优秀专家多名，一些优秀年轻教授已成为本学科未来发展的主要 学术骨干和带头人。 本学科（本系）以从事基础研究为主，同时开展应用课题和器件的研究。 1986年以来获国家发明奖1项、国家教委（现国家教育部）科技进步奖10项、上 海市科技进步奖6项。其中本年度获上海市科技进步三等奖1项、国家专利1项。 获全国优秀博士论文1项。2000年承担国家自然科学基金委项目19项，其中重点 3项。承担攀登计划2项，863项目2项，国家教育部基金9项（其中跨世纪优秀人 才计划和优秀年轻教师基金各1项），上海市科委基金12项（其中重大和重点各 1项）、上海市教委基金2项。2000年各类基金总到款288万元。 目前共承担项目47项，有国家自然科学基金项目18项（含重点2项），攀登 计划2项、863项目1项、973项目1项等国家项目以及省部委项目15项。其中包括 国家杰出青年基金1项。 本学科设备先进，拥有飞秒、皮秒、纳秒、高分辨率等大型激光器，多套 成膜设备及各种光学、电子学测量仪器，总投资超过两千万元。 本系新专业“光信息科学与技术”已获国家教育部批准，将于2001年在全 国招收本科生。光学楼已获得兴业证券公司的捐赠和校方的支持，将于2001年 夏季进行大修，2001年9月我们将以崭新的光学楼迎接新生的到来。 目前主要研究方向有：1．超短脉冲激光与物质相互作用及超快光物理； 2．光子学物理基础和器件；3．固态物质的光学和光谱性质；4．光电子功能材 料和电荷转移过程；5．光生物学和激光医学。（详见课题进展） 2 我室聘请的名誉教授和顾问教授 Honorary and advisory professors of the Lab N.Bloembergen 美国哈佛大学教授，诺贝尔物理学奖获得者 Prof. N.Bloembergen, Harvard University, U.S.A. 沈元壤 美国加州大学伯克利分校教授 Prof. Y.R.Shen, U.C.Berkerley, U.S.A 张国鼐 美国耶鲁大学教授 Prof. R.K.Chang, Yale University, U.S.A. 厉鼎毅 美国AT&T 公司及Bell实验室教授 Prof. T.Y.Li, AT&T Bell Lab, U.S.A 唐孝威 中科院北京高能所研究员，中科院院士 Prof. Xiaowei Tang, Academician, Insititute of High Energy Physics, Chinese Academy of Sciences 徐至展 中科院上海光机所研究员，中科院院士 Prof. Zhizhan Xu, Academician, Shanghai Institute of Optics & Fine Mechanics, Chinese Academy of Sciences 杨国桢 中科院北京物理所研究员, 中科院院士 Prof. Guozhen Yang, Academician, Insitute of Physics, Chinese Academy of Sciences 侯洵 中科院西安光机所研究员，中科院院士 Prof. Xun Hou, Academician, Xian Institute of Optics & Fine Mechanics, Chinese Academy of Sciences 干福熹 中科院上海光机所研究员/复旦大学教授，中科院院士 Prof. Fuxi Gan, Academician, Shanghai Institute of Optics & Fine Mechanics, Chinese Academy of Sciences 范滇元 中科院上海光机所研究员，工程院院士 Prof. Dianyuan Fan, Academician, Shanghai Institute of Optics & Fine Mechanics, Chinese Academy of Sciences 钟业华 美国西北大学材料系教授 Prof.Yip-Wah Chung, North-West University, U.S.A 3 课 题 进 展 Progress in Research Projects 4 功能薄膜材料的光物理特性研究 Studies on Optic-physical Properities of Functional Film Materials (一) 电 荷转 移有 机复 合材 料的 光电 特性 研究 Study on optical and electric properties of complex material with charge transfer (1)利用物理喷束淀积技术（PJD）与旋转涂敷法相结合，制备了以下四类纯膜 和复合膜：金属富勒烯盐; 金属酞青；C60/PPV分层和混合膜；金属酞青/PPV分 层膜。 Four kinds of functional films were made by the means of Phyical Jet Deposition (PJD) and spin coating, which were Metal Fullerene, Metal Phthalo-cyanine, C60/PPV multilayers or mixed layers and Metal Phthalocyanine/PPV multilayers. (2)研究了上述四种电荷转移体系的正反向电流特性和光生伏打效应，用界面偶 极层模型研究了金属-有机物及有机材料之间界面的能级结构，解释了界面整流 效应和光生伏打效应的增强。 Physical Jet Deposition (PJD) method was used to form the C60Ni films, one of the metal doped[60]fullerenes films, which were made into the Al/C60Ni/ITO (indium/tin-oxide) layered structure photovoltaic cells. The photovoltaic effect and the current-voltage characteristic in dark with the devices were taken. Compared with the Al/C60/ITO layer structure devices, the enhancement of photovoltage and rectification rate of C60Ni devices was found. Possible reasons were discussed. (3)研究了C60掺杂的PPV电荷转移体系的光谱特性，包括可见-紫外吸收谱。稳 态荧光谱，瞬态荧光谱，观察到PPV吸收峰明显的抑止和PPV荧光峰的淬灭。 测量了混合体系的荧光寿命。与实验相关的电荷转移的机制正在研究中。 we study the optical properties of the charge transfer system in poly[2-methoxy-5-(2’-ethyl-hexyloxy)-1,4-phenylene vinylene](MEH-PPV), which was doped by C60 with different consistence, by means of ultraviolet-visual absorption spectroscopy, steady-state photoluminescence (PL) and time-resolved photoluminescence (TRPL). We observed the restraining effect of absorption peak and PL quenching of fluorescence, which is regarded as the formation of complex compound in the mixed conjugated polymer. The formation is the result of the strong interaction of π - π conjugated system in the base state in the films, which associated with the direct MEH-PPV to C60 charge transfer. In the excited state, the excited charge transfer advanced the restraint of luminant transiton process, which strengthen the PL quenching of MEH-PPV. (4)已发表论文二篇，待发表论文二篇。 (二) 非对称II-VI族耦合多量子阱的光学非线性研究 Second Nonlinear Optical Properties of ZnCdSe/ZnSe Quantum Wells (1)用反射光学二次谐波产生研究了Zn1-xCdx Se/ZnSe非对称耦合多量子阱的界面 效应，证明多量子阱材料随着阱间耦合的增强，描写不对称量子阱间电荷转移 （ ） 的电子波函数交叠变大，二阶非线性系数χ 2 增大。同时发现随着Cd含量的增 （ ） 大Zn1-xCdx Se势阱禁带宽度变小χ 2 变小。 5 SHG intensity in strained Zn1-xCdx Se/ZnSe asymmetric coupled quantum wells is at least one order of magnitude larger than that form bulk ZnSe due to the centrosymmetry-breaking effect resulting from the strong interwell coupling interaction. It is also strongly dependent on the QW parameters. SHG intensity was found to increase with decreasing barrier width or cadmium concentration x (barrier height, well depth). Furthermore, an obvious in-plane anisotropy was observed with a period of 180o in our measured ratios of p in to p out and s in to p out SHG intensities. The s out SHG intensity versus the incident polarization angle displayed a periodic feature, I s (α p ) ∝ Sin(2α p ) 2 2,while the p out SHG intensity varies in a relatively complex way, which agreed well with the theoretical calculations. (2)待发表论文三篇。 (三) 有机功能材料超薄膜的荧光光谱及非线性特性研究 Nonlinear optical investigation of the organic thin films (LB) （1）我们用微扰方法研究了有机分子膜中淀积过程诱导的平面内分子定向 排列（各向异性）特性，从理论上推导了二次谐波强度与基频光、倍频光的偏 振方向，及基板上拉膜方向的关系，与实验符合良好。[Applied Optics, 39(21), 2000: 3781-3784] Dipping-induced in-plane anisotropy in organic molecular films was characterized by using second harmonic generation (SHG) measurement and analyzed by using a new perturbation method. We derived theoretical formulas for the dependence of SHG intensity on the polarizations of incident fundamental beam, output second harmonic beam and the azimuthal angle of samples, which agreed well with our experimental measurements. (2)利用稳态和时间分辨荧光及吸收方法研究了不同供-受电子基团半花菁 分子在LB多层膜中的H-聚集体性质。我们发现聚集程度主要取决于供电子基团 的结构。较大的供电子基团或花生酸的混入可导致较低的聚集度。时间分辨荧 光被证明是定量表征有机分子聚集体寿命、大小与组份的有力工具。[Submitted to J phys. Chem. Solid, Sep. 2000]。 Influence of molecular composition in hemicyanine Langmuir-Blodgett (LB) films on the aggregation features was investigated by using steady state and time-resolved photoluminescence spectroscopies. It was found that a lower degree of H-aggregation (smaller aggregate size) could be realized in hemicyanine LB films with larger donor groups, leading to a smaller photoluminescence peak blue shift with respect to their solution spectra and longer aggregate lifetime. (3) 利用二次谐波产生技术首次研究了氧化铟锡薄膜的非线性光学特性。氧 化铟锡薄膜中多晶晶粒的优先取向，使其产生了非常强的二次谐波信号，并且 在一定的薄膜厚度以上，随薄膜厚度的增加二次谐波信号显著增强。由于多晶 晶粒的优先取向使得薄膜基板平面内存在着非常明显的非线性光学各向异性。 Second harmonic generation (SHG) from indium tin oxide (ITO) films on glass substrates has been investigated in detail for the first time. Significant SHG intensity and nonlinear optical anisotropy was observed from ITO films due to orientation of 6 the crystal cells. The SHG reached a maximum in intensity at an incident angle of 60 ° . The effective second order nonlinear optical susceptibility χ (2)eff was about 2.4×10-10esu. (4) 利 用 吸 收 谱 和 二 次 谐 波 产 生 （ SHG ） 技 术 研 究 了 温 度 对 半 花 菁 Langmuir-Blodgett（LB）多层膜的膜结构和非线性光学特性的影响。LB膜的二 次谐波强度随温度的变化开始随温度的增加而增加，最大值约在45°C左右，然 后随温度的增加而减小。在半花菁与花生酸或花生酸铬交替的LB多层膜中，由 于花生酸的融化，导致膜结构的变化，使得二次谐波强度随温度变化的有一个 突变点。线性吸收谱表明半花菁分子在LB多层膜中形成了H-聚集体，并且加热 可以使聚集体分解。 Molecular structure and optical nonlinearity in interleaving hemicyanine/arachidic acid or cadmium arachidate multilayers, and Z-type pure hemicyanine multilayers were investigated as a function of the temperature by means of second harmonic generation (SHG) and linear absorption. The SHG intensity shows a maximum at about 45 ° C in the multilayers. An inflection was observed in the temperature dependence of SHG intensity in the interleaving hemicyanine/arachidic acid and hemicyanine/cadmium arachidate multilayers, and was attributed to melting of arachidic acid or cadmium arachidate. The absorption spectra show that the molecules in the multilayers formed H-aggregates which could be dissociated by heating. (5) 利用时间分辨荧光和三维荧光谱对LB多层膜中半花菁分子的聚集行为 和激发态特性进行了研究。在半花菁/花生酸交替的Y型多层膜中，半花菁分子 形成的H-聚集体引起其三维荧光谱蓝移，并且荧光峰随时间的变化逐渐向红光 方向移动。由时间分辨荧光得到LB膜中的聚集体平均约包含9个半花菁分子， 并且由于聚集体内所有分子间的相互作用（耦合）相干叠加，使得LB膜的荧光 衰减较快。 The properties of aggregates and excited state were investigated by using time-resolved fluorescence and 3D fluorescence spectra techniques in Langmuir-Blodgett multilayer films. As interaction of hemicyanine molecules caused formation of H-aggregates and a blue shift of the 3D fluorescence spectra in interleaving hemicyanine/arachidic acid multilayers. The peak of fluorescence was a red shift along with the time decay. The size of aggregate can be obtained by time-resolved fluorescence. It is about 9 hemicyanine molecules. The lifetime of the LB fluorescence is much shorter than that of the hemicyanine solution due to the stronger intermolecule interactions in the aggregates. (6)已发表论文5篇 7 飞秒时域的非线性光学研究 Investigation on nonlinear optics in femtosecond time scale 一、 探索新的色散物理机制，创造产生全维数时空光孤子的实验室环境 1． 物理上发现了非线性过程感应群速度色散的机制 以往群速度色散的机制均是线性的， 如材料本征色散、模式色散及角色散等。 我们基于对飞秒光脉冲经非线性传输的深入研究及物理图像上的全新认识，发 现了非线性过程也能感应群速度色散的物理现象，并建立了其物理图象。该新 颖的色散机制来源于χ(2): χ(1)级联非线性过程。本项工作不但拓展了对群速度色 散这一基本光学问题的物理认识，而且具有重要的科学价值。 2. 创造产生全维数时空光孤子的实验环境 基于我们对非线性感应群速度色散的物理发现，创造了利用现有材料科学 及飞秒光学技术能实现的条件来产生全维数的光孤子（光子弹）的实验室环境。 “光子弹”的实验产生是光学孤子物理研究的最终目标之一，其学术意义重大。 二、其它非线性光学方面的研究结果 1. 非线性谐波转换过程中光束质量的传输变换规律 线性被动光学系统不会改善光束质量M2因子，受非线性过程处理手段的限 制，很难有效地讨论非线性光学系统中M2因子的传输变换规律。基于调制微扰 理论，我们成功地掌握了倍频或三倍频过程对M2因子的影响规律。在谐波转换 过程中，M2因子光束质量将变差，然而光束的发散角基本保持不变。 2. 准位相匹配（QPM）结构晶体（PPLN）在改善光束质量M2因子上的应用 应用时空等价的物理图像进行类比，我们发现特殊设计的PPLN晶体可以构 建可控的空间相移，从而能够有效地补偿激光的各类位相畸变，产生近衍射极 限的输出激光束。该项工作有望在产生衍射极限的高功率短波长半导体激光方 面发挥作用，同时能够保证整个器件的集成化。 1. Nonlinearly induced group-velocity dispersion (GVD) GVD is an important issue related with femtosecond optics, which was generally recognized as a linear behavior. Based on the deeply investigation on nonlinear propagation of femtosecond lasers, we found that nonlinear frequency conversion can also induce GVD. The novel scheme of this nonlinear induced GVD is a cascade process of χ(2)(2ω:ω,ω) : χ(1)(ω) or χ(2)(ω:2ω,-ω) : χ(1)(2ω). 2. A feasible laboratory environment to generate 4D optical solitons. The generation of 4D optical solitons or bullets is one of the most important directions in soliton physics, and is of great scientific significance. Benefited from the novel GVD induced in frequency conversion, we reached a state to approach the generation of 4D optical solitons experimentally. The required laboratory conditions are experimentally feasible with the advance of material science and femtosecond optics. 3. Analysis of beam-quality degradation in nonlinear frequency conversion Based on the transfer of electric-field amplitude and phase ripple in frequency 8 tripling, simple formulas are derived for the harmonic laser beam-quality factor, M23w , with an arbitrary fundamental beam incident to ideal nonlinear crystals . Harmonic beam-quality is generally degraded, while the beam divergence is similar to that of the fundamental after a nonlinear frequency-conversion process, For practical crystals with periodic surface ripples due to their machining , a multi-order diffractive model is presented to study the focusing properties of harmonic beam. Predictions of the theories are shown to be in excellent agreement with full numerical simulation of tripling. 4. Beam-quality improved efficient second-harmonic generation in aperiodic quasi-phase-matching gratings We propose a simple means for improving optical beam quality with second-harmonic generation. By creating spatial walk-off in aperiodic quasi-phase-matching gratings, we show that the harmonic beam experiences a spatial phase shift that can be engineered to correct for arbitrary phase distortions. Diffraction-limited beam quality can be realized without scarifying the conversion efficiency. 9 低维磁结构的磁性和非线性光学响应 Magnetic properties and nonlinear optical response in low-dimension magnetic structures ① 磁 性 薄 膜的 光 学 二 次 谐波 测 量 Measurements of optical second harmonic generation (SHG) on magnetic thin films 本年度完成了大气中磁诱导二次谐波(MSHG)的搭建和测量工作，从而为 超高真空系统到来后的在位测量做好了前期准备。探测到单层不同厚度的磁性 薄膜Co在p 和s偏振入射时的MSHG信号，发现p偏振时磁信号较s偏振时大一个 数量级，且得到其非线性磁光克尔旋转角达2.5度，较其线性磁光克尔旋转角大 很多。当Co薄膜厚度从4 nm变成100 nm时，MSHG信号变号，反映了界面和表 面共同作用的结果（100 nm时差不多全是表面的贡献）。在4 nm的Co膜上覆以 很薄的非磁性Cu膜也同样会使信号反号，此时Co的表面变成了界面。 We finished the construction of magnetization-induced SHG (MSHG) setup and some measurements in the air, being ready for the in-situ measurements on the soon coming MBE system. The MSHG hysteresis curves were detected for the single Co films grown by sputtering with different thickness, in p- and s-polarized input light. It was found that the signal for p-input was one magnitude larger than that for s-input and its nonlinear Kerr rotation was 2.5 degrees, much larger that the linear one. The magnetic second harmonic intensity changed its sign when the thickness of Co film went thicker to 100 nm where only surface part contributed to the signal. The same behavior happened if covered with a 1 nm Cu film on the top of a 4 nm-thick Co film. It is not difficult to be understood if we recall that the MSHG signal results combinedly from both surface and interfaces. ② 平面掺杂磁性多层膜的巨磁电阻 Planar doping effect on GMR in magnetic multilayers 利用SiO2-Ni颗粒膜的界面掺杂（0.3 nm厚），使Co/SiO2-Ni/Cu/Co的巨磁电 阻行为发生了较大的变化，磁电阻变化为3.2%，开关场只有± 10 Oe和± 60 Oe， 同时其峰值宽度达到了30 Oe，较Co/Cu92Mn8/Co又有较大改善。我们认为SiO2-Ni 的加入首先使层间耦合较大的降低，显示出隧道结的作用。同时此夹层的加入使 界面得到改变，从而使得开关机制得到很好的体现。 A very large change of GMR behavior was found in Co/SiO2-Ni/Cu/Co sandwiches by inserting a very thin granular SiO2-Ni film (0.3 nm thick). Its GMR ratio was 3.2% and the switching fields were ± 10 Oe, ± 60 Oe, with the width of the peak about30 Oe, which was largerly modified comparing to the Co/ Cu92Mn8/Co case. We think the adding of insulating SiO2-Ni thin layer deduces the interlayer coupling between two Co films and meanwhile modified the interface, thus revealing the switching mechanism. ③ 磁动力学研究 Study of magnetic dynamics. 采用钛宝石飞秒激光作用产生的磁诱导光学二次谐波，搭建了磁性动力学的 泵浦-探测装置，并作了初步的测量。 A pump-probed MSHG setup was finished for the study of the magnetic ultrafast 10 phenomena by using the Ti-sapphire laser (Regenerated amplifier). A preliminary measurements were taken. 本年度发表2篇EI论文，接受国内刊物（海外版）1篇和SCI论文2篇。会议报 告有第四届国际薄膜物理和应用会议上的口头报告（2篇）、在巴西举行的国际 磁学会议上的张贴报告、第二届亚太激光讨论会的口头报告和全国磁性薄膜和纳 米磁学会议报告2篇。获教育部优秀年轻教师基金、教育部科学技术重点基金和 973项目分课题各1项，并获2001年启动的国家杰出青年基金。 Three papers were published and two were accepted. The presentations in conferences are: 4th International Conference on Thin Film Physics and Applications, International Conference on Magnetism, 2nd Asian Pacific Laser Symposium, and 2nd National Conference of Thin Films and Nano-magnetism. New grants: Excellent Young Teacher Foundation and Key Foundation for Science & Technology of State Education Ministry, 973 project (part), and Outstanding Young Scientist Foundation (from 2001). 11 团簇光物理 Photophysics of fullerenes and silica clusters 一、富勒烯金属化合物的激光烧蚀飞行时间质谱研究：金属富勒烯的形成 Laser ablation of metal fullerides: Formation of metallofullerenes 富勒烯的金属掺杂可能形成具有不同构型及性质的金属富勒烯,因而引起 人们兴趣。我们利用 308nm 准分子激光烧蚀多种化学合成的富勒烯金属化合物 C60Mx (M=Sm, Pt,Ni,Rh,La,Y), 飞行时间质谱研究发现这些衍生物的光诱导转 化过程随金属的不同而异。激光烧蚀C60Smx , C60Ptx , C60Nix 主要形成以C59M为主 的杂笼金属富勒烯（heterofullerenes），原在笼外的金属原子取代 C60笼上的碳 原子形成取代型金属富勒烯。C60Lax , C60Y x在激光烧蚀下只形成由偶数碳原子组 成的C2nLa 及C2nY系列。与(C 60+O3)/La2O3或Y 2O3 压片样品烧蚀结果的比较表明 La、Y可能进入笼内形成内嵌金属富勒烯La@C2n, Y@C 2n 。C60Rhx 的烧蚀质譜则 更丰富，包括C2nRh及C2n+1Rh 两个系列，其结构在研究中。此项研究表明激光 烧蚀可使金属原子从笼外转到网架上取代碳原子或嵌入笼内，提供了一种制备 各种金属富勒烯的方法。 Doping of fullerenes is an interesting topic in fullerene research because it can form various types of metallofullerenes with different properties. A variety of chemically synthesized metal fullerides C60Mx (M=Sm,Pt,Ni,Rh,La,Y) have been studied by 308nm laser ablation. Mass spectrometric measurement indicates that the laser-induced transformation process depends on the metal doped. In the laser ablation of C60Sm x, C60Ptx , and C60Nix , substitutional heterofullerenes, mainly C59M, with M substituting one of the carbon atoms of the cage, are formed. Laser ablation of C60La x and C60Yx yields only metallofullerenes composed of even-number of carbon atoms. A comparison with the laser ablation results from composite samples of ozonized C60 and La2O3 or Y2O3 indicates that La or Y may be inserted into the cage forming endohedral metallofullerene La@C60 or Y@C60. The mass spectra of C60Rhx are more interesting, two sequences C2nRh and C2n+1Rh appear, the structures of which are under investigation. Our research illustrates that laser ablation can transform the metal atoms from exohedral sites to network substitutional or endohedral sites, providing a method for the preparation of various metallo-fullerenes. 二 、 奇 数 碳 笼 团 簇 的 实 验 和 理 论 研 究 The experimental and theoretical investigation of odd-numbered “fullerene” clusters 继在多种富勒烯衍生物的激光烧蚀研究中发现对奇数碳笼团簇形成的增强 作用后，我们又在对掺C60气凝胶的研究中发现形成特别强的奇数碳笼团簇C55。 更值得注意的是：在对富勒烯金属化合物C60Mx的烧蚀研究中，都观察到在负离 子通道中奇数碳笼团簇的形成。我们用遗传算法计算奇数碳笼团簇的结构，发 现其最低能量异构体具有带一个两配位碳原子的准笼形结构。此两配位碳原子 在激光作用下比较容易断键形成窗口。联系奇数碳笼团簇中间产物的形成，我 们用“窗口”模型讨论了取代型和内嵌型金属富勒烯的形成机理。 12 Following the observation of the enhancement of odd-numbered “fullerene” cluster formation from the laser ablation of many fullerene derivatives, we have found the appearance of ultra intense C55 from a sample of C60-doped silica aerogel. Of particular worthnoting is the observation of the odd-numbered “fullerenes” from the laser ablation of metal fullerides in the negative ion channel. We have calculated the structures of the odd-numbered “fullerenes” and found that the lowest energy isomers have pseudo-cage structures with a two-fold coordinated carbon atom in each cage. Due to the easier opening of the pseudo-cage we discuss the formation of the substitutional and endohedral metallofullerenes through the odd-numbered “fullerene” intermediate by means of the “window” mechanism. 三、紫外激光烧蚀多孔二氧化硅材料的研究：二氧化硅幻数团簇的形成及结构 计 算 UV laser ablation of porous silica materials: Formation of magic number silicon dioxide clusters and the structure calculation 对大量多孔二氧化硅材料的激光烧蚀研究都观测到丰富的二氧化硅团簇 系列。我们在对掺 Rhodamine 6G 的二氧化硅气凝胶的实验中首次观察到幻数团 簇 [(SiO 2)n O2H3]-,n=4,8. 用 Gaussian 94 计 算 中 性 团 簇 (SiO 2)4O2H4 及 负 离 子 [(SiO 2)4O2H3]-的结构，给出两者的最低能量结构均为三维笼形，对称性分别为 S4 和 C3。幻数团簇的研究对于新材料的发现有所启示。 From the laser ablation of a majority of porous silica materials, abundant silica cluster sequences have been observed. We studied the formation of magic number silicon dioxide clusters [(SiO2)n O2H3]- with n=4,8 for the first time. Theoretical calculation with Gaussian 98 shows that the neutral cluster (SiO 2)4O2H4 and the anionic cluster [(SiO2)4O2H3]- take the 3-dimensional cage structures with symmetries S4 and C3 respectively. The study of magic number clusters might shed light on the discovery of new materials. 四、富勒烯团簇的光限幅特性研究：固体光限幅材料的制备 Optical limiting properties of fullerene derivatives: Fabrication of fullerene derivative doped glass 寻找具有良好光限幅性能及溶解性能的富勒衍生物并将掺杂于玻璃中，制 固体光限幅材料是激光防护研究中的一个重要课题。我们测试分析了系列富勒 烯衍生物，发现 C60C9H7-C9H7 具有良好的光限幅性能，并且溶于极性溶剂。基于 此，我们利用溶胶-凝胶方法成功地将其掺入固体玻璃中, 得到了具有良好光学 性能的均匀材料，初步测试表明该掺杂玻璃是制备光限幅器件的良好材料。 Our investigation of optical limiting properties of series fullerene derivatives shown that the Diels-Alder mono-adduct of C60 with 1,1’-biidene is a promising candidate for the fabrication of practical optical limiting devices. This derivative not only posses good optical limiting properties in toluene as C60, but show good solubility in polar solvents which is advantageous to the fabrication of the derivative-doped xerogel glass. Using sol-gel technique, the derivative molecules were successfully incorporated into glass. Solid sample with low scattering and obvious optical limiting properties has been obtained. 五．表面自扩散及富勒烯团簇结构的理论计算 Theoretical calculations of adatom diffusion and structures of fullerene clusters 1．用静态能量计算及分子动力学方法进一步系统地研究了EAM金属fcc(100)表 13 面的自扩散机制. 给出了关于金属fcc(100)表面自扩散机制的一般性规律；2． 进一步研究了吸附原子在 Pt(100)表面的自扩散机制. 对所观察到的以二聚物 形式扩散的机制进行了详细的分析；3．采用原子嵌入势,用分子动力学方法系 统地研究了金属fcc(111)表面的自扩散机制. 结果表明在fcc(111)表面, 交换 扩散的机制也有可能出现, 而且这种扩散过程只能在hcp吸附位之间发生；4． 用PRP( Pacheco and Ramalho potential)势描述(C60)n团簇, 采用遗传算法并 结合数据库的共轭梯度方法系统地研究了C60)n团簇的最低能量结构. 考虑温 度效应后, 我们所给出的结果与实验结果相吻合. (1) Adatom diffusion mechanisms on metal fcc(100) surfaces is studied further by a systematic static calculation and molecular dynamics based on a series of embedded-atom method(EAM). A generic law about the diffusion mechanisms on metal fcc(100) is given. (2) The diffusion mechanisms on Pt(100) surface is studied further. An ad-dimer diffusion mechanism is observed and analyzed in details. (3) On a series of fcc(111) surfaces modeled by embedded-atom method (EAM), adatom diffusion mechanisms are studied systematically by molecular dynamics. The results show that the exchange mechanism is also possible besides the well-known hopping mechanism, and exchange diffusion process only occurs between the hcp sites. (4) The lowest energy structures of fullerene clusters (C60)n(n<57) described by the Pacheco and Ramalho potential(PRP) are systematically optimized by a global optimization procedure which combines the genetic algorithm and database conjugate gradient method. When the thermal effect is considered, our results are in good accordance with that in experiment. 14 玻璃基质光波导：材料、物理与器件 Glass optical waveguides: materials, physics and devices 1. 玻璃基质光波导器件制备 Fabrication of glass optical waveguide devices 采用溶胶-凝胶技术制备了折射率和厚度符合要求的有机/无机复合低损耗 波导，条形光波导损耗达0.5dB/cm。在此基础上，制备了1x4玻璃光波导分波合 波器件，掌握了分叉波导制备的关键工艺及V形槽制备工艺，解决了波导与光纤 之间耦合的关键技术。经测量该器件的插入损耗为 8.7dB(其中附加损耗为 2.7dB)，分束比偏差为7.5%。完成市科委项目原定的技术指标，通过了市科委 组织的鉴定。 Low loss glass planar waveguide with aquired refractive index and thickness were fabricated by sol-gel technique. Ridge waveguides were made with transmission loss as low as 0.5 dB/cm. A 1x4 glass waveguide splitter was fabricated which was coupled to single mode fibers that were packaged on silicon V-grooves. The insertion loss of the device was 8.7 dB(6 dB of 1x4 splitting, 2.7 dB of additional loss). 2. 有机分子掺杂光波导二阶光学非线性研究 Second order optical nonlinearity of organic dye doped optical waveguides 和复旦大学材料系合作，研究了一种新合成的有机分子链接密胺聚合物薄 膜的制备，进行了二阶光学非线性和热稳定性的研究。研究发现，和有机分子 掺杂型聚合物相比，链接型聚合物的热稳定性进一步提高，该材料的玻璃化转 变温度已超过200℃，160℃下可很好地保持二阶光学非线性的稳定性。 A new organic dye side-chain linked melamine formaldehyde resin was synthesized, thin films from this polymer was fabricated and its second order nonlinearity was studied. The glass transition temperature of the polymer thin film is over 200 degree C, second harmonic generation(SHG) intensity of the film was stable at temperature as high as 160 degree C. 3. 玻璃态材料的二阶光学非线性的产生机理研究 Mechanism of second order optical nonlinearity generation from glassy materials 受国家自然科学基金委资助，与美国依阿华州Coe College的S. Feller教授领 导的玻璃研究组开展国际合作研究，取得以下结果： (1)详细研究了PbO/B2O3 玻璃中平板极化诱导产生的二阶光学非线性。发现该 玻璃中的二阶光学非线性系数c (2)(z)在整个体内都存在，并具有非均匀分布。(2) 发现在SiO 2（熔石英）块状玻璃中，不同的极化方法（平板电极极化和电晕放 电极化） 对诱导产生的二阶光学非线性有显著的影响。这一发现可以解释从1991 年以来国际上各个不同研究小组所发表的结果的差异。(3)提出在极化过的玻璃 中存在“诱导偶极子”的理论模型，解释了文献中及我们自己测量到的实验结 果：在SiO 2-GeO 2玻璃薄膜中光学二次谐波强度ISHG与平板极化电压Vp之间具有 超平方关系，ISHG ∝Vpt, 2