Ultrafast non-linear optical properties of Ge20As25Se55 chalcogenide films

The non-resonant third-order non-linear optical properties of amorphous Ge₂₀As₂₅Se₅₅ films were studied experimentally by the method of the femtosecond optical heterodyne detection of optical Kerr effect. The real and imaginary parts of complex third-order optical non-linearity could be effectively separated and their values and signs could be also determined, which were 6.6 × 10⁻¹² and −2.4 × 10⁻¹² esu, respectively. Amorphous Ge₂₀As₂₅Se₅₅ films showed a very fast response in the range of 200 fs under ultrafast excitation. The ultrafast response and large third-order non-linearity are attributed to the ultrafast distortion of the electron orbitals surrounding the average positions of the nucleus of Ge, As and Se atoms. The high third-order susceptibility and a fast response time of amorphous Ge₂₀As₂₅Se₅₅ films makes it a promising material for application in advanced techniques especially in optical switching.     

800nm激光泵浦掺Nd^3＋的氟化物玻璃光纤正向双程超荧光分析

从实验上探讨了掺Ｎｄ＾３＋的氟化物玻璃光纤正向双程超荧光基本特性，包括输入－输出特性、输出－带宽特性以及输出－波长（激发）特性。并给出了理论上的拟合公式，实验表明利用氟化物玻璃光纤有望获得性能优异的有应用前景的低相干度集成化光源。     

Optical Nonlinearity of Hybrid and Nanocomposite Materials Prepared by the Sol-Gel Method

In this paper the nonlinear refractive index, optical limiting effect, photoinduced and electroinduced second harmonic generation of dye-doped hybrid and nanoparticle-doped composite materials prepared by the sol-gel process have been reported. The origin of these nonlinear optical effects has been discussed.     

Enhancement of three-photon absorption cross-sections in a novel class of symmetrical charge transfer fluorene-based molecules

The three-photon absorption effect (3PA) of two novel symmetrical charge transfer fluorene-based molecules (abbreviated as BASF and BMOSF) has been determined by using a Q-switched Nd:YAG laser pumped with 38 ps pulses at 1064 nm in DMF. The measured 3PA cross-sections are 84 × 10⁻⁷⁸ and 114 × 10⁻⁷⁸ cm⁶ s², respectively. The geometries and electronic excitations of these two molecules are systematically studied by PM3 and ZINDO/S methods. The relationships between 3PA cross-sections and intramolecular charge transfer are discussed micromechanically. The experimental and theoretical results have shown that the larger intramolecular charge transfer, which was characterized by the charge density difference between the ground state (S₀) and the first excited state (S₁), the greater enhancement of the 3PA cross-sections.     

光(热)致变色剂:单和双吲哚啉螺苯并吡喃

用乙醇作溶剂,在哌啶存在下,通过2,3,3-三甲基-N-(β-羟乙基)吲哚啉碘化物(1)与3-或5-硝基水杨醛反应,分别制得螺环异构体(2a)与(2b)。它们再进一步与异氰酸苯酯进行加成反应,合成一对单螺环异构体(3a)与(3b),将2a 与2b 分别和2,4-二异氰酸甲苯酯(TDI)反应,合成一对双螺环异构体(4a)与(4b)。2a,3a,4a,4b 是光致变色化合物;2b 与3b 是热致变色化合物。     

Marangoni effect induced micro/nano-patterning on Sb<Subscript>2</Subscript>Te<Subscript>3</Subscript> phase change thin film by laser pulse

Thermocapillary and chemicapillary effects are known to coexist in a material molten pool when irradiated by a pulse laser. According to the effects, we fabricate various patterns with different shapes on a Sb₂Te₃ phase change thin film by precisely adjusting the pulse energy. In this process, the laser power is fixed at 5.0 mW, and the pulse width is adjusted from 100 ns to 5 ns. The shape of the patterns gradually changes from a dimple-bowl shape, a dome shape, a “Sombrero” shape to a deep-bowl shape following an increase in the pulse energy, which corresponds to the crystallization-threshold, bump-threshold, rupture-threshold, and ablation-threshold of the material. The different patterns are the results of the competition between the thermocapillary and chemicapillary effects in the molten pool, which determine the nature of the flow and lead to the different patterns in different laser parameters.     

Film-thickness Error Analysis of Optical Disk Systems

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｒｅｃｅｎｔｌｙｏｐｔｉｃａｌｄｉｓｋｓａｂｌｅｔｏｓｔｏｒｅａｌａｒｇｅｑｕａｎｔｉｔｙｏｆｉｎｆｏｒｍａｔｉｏｎｈａｖｅｂｅｅｎｕｓｅｄａｓｃｏｍｐａｃｔｄｉｓｋ (ＣＤ ) ,ｄｉｇｉｔａｌｖｅｒｓａｔｉｌｅｄｉｓｋ(ＤＶＤ) ,ａｎｄｔｈｅｉｒｒｅｃｏｒｄａｂｌｅｏｒｒｅｗｒｉｔａｂｌｅｔｙｐｅｓ(ｓｕｃｈａｓＣＤ Ｒ ,ＣＤ ＲＷ ,ＤＶＤ Ｒ ,ａｎｄＤＶＤ ＲＡＭ ) [1 ] .Ａｎｏｐｔｉｃａｌｄｉｓｋｉｓａｋｉｎｄｏｆｍｕｌｔｉｌａｙｅｒｓｙｓｔｅｍｄｅｐｏｓｉｔｅｄｏｎａ…     

新型衬底晶体LiGaO2的生长和结晶性质研究

氮化物长期以来被看作是在蓝光及紫外波段光电子应用中最有希望的材料[1].但在改进材料质量方面最大的困难是:缺乏一种能和GaN在晶格及热性能方面十分匹配的理想衬底材料[2].Al2O3被普遍认为可以作为GaN的衬底材料.这主要是由于它具有的结构、热性能好,和生长加工容易等特点.     

偏磷酸根(PO-3)对氟铝酸盐玻璃透光性能影响

在氟铝酸盐玻璃（AMCSBY）中引入Ba(PO3）2替代BaF2,替代公式为10MgF2-20CaF2-(10-x)BaF2-10SrF2-15YF3-35AlF3-xBa(PO3)2(x=,2,4,6,8)。对玻璃进行了差热分析，结果表明，在氟铝酸盐玻璃中引入偏磷酸盐使玻璃形成能力大大提高；测量了玻璃从紫外到红外的透过光谱和紫外吸收光谱，在玻璃中引入偏磷酸钡使玻璃中红外透过能力下降，红外吸收边带移向短波段，玻璃紫外透过能力得到提高。紫外吸收边带移向紫外波段，由于PO3^-的影响，O－H吸收峰由2830nm移到3145nm。     

磁控溅射法制备的高反Ag_5In_5Te_(47)Sb_(33)相变薄膜的光谱性质及短波长静态记录性能

研究了磁控溅射制备的Ａｇ５Ｉｎ５Ｔｅ４７Ｓｂ３３相变薄膜的光谱及短波长静态记录性能。研究结果表明，晶态薄膜反射率较高，并在６００～９００ｎｍ波长范围内，晶态与非晶态的反射率和折射率相差很大。在ＣＤ－Ｅ系统的工作波长７８０ｎｍ处，晶态反射率高达５０％，光学常数为５．３４－１．０ｉ；非晶态反射率为２３％，光学常数为２．５－１．０３ｉ。从这一角度讲，Ａｇ５Ｉｎ５Ｔｅ４７Ｓｂ３３相变薄膜适于做ＣＤ－Ｅ系统的记录介质。另外，采用波长为５１４．４ｎｍ的短波长光学静态记录测试仪对Ａｇ５Ｉｎ５Ｔｅ４７Ｓｂ３３薄膜的记录性能进行了测试，结果表明，这种薄膜短波长记录性能较好，它在较低功率和短脉宽的激光束作用下就可得到较高的反射率对比度。