同步极化聚合及原位二次谐波测试系统的研制

采用同步极化聚合,有效地降低了极化聚合物极化温度。报道了实现这一过程的装置的研制,并结合采用原位二次谐波测试系统实现了对极化过程的实时监测。利用该系统对耐高温聚酰亚胺的极化动力学进行了研究,该聚合物极化膜的ｄ３３值为１５ｐｍ／Ｖ,取向在１９０℃时才开始衰减,具有很好的取向稳定性。     

极化聚合物薄膜电光系数的实时测量

提出了一种极化聚合物薄膜电光系数的实时测量方法。实验结构由耦合棱镜和依次制备在棱镜底面的四层薄膜组成,这四层薄膜分别是金属层（作为上电极）、极化聚合物,缓冲层和下电极。包含导波共振角并具有一定角度的入射光线会聚于棱镜底面,然后用CCD探测拍摄反射光斑,当外加电场作用于上下电极时,就可从光斑暗线位置的变化测量极化聚合物薄膜的电光系数。在测量过程中,使用了计算机图像处理方法和光学空间滤波技术。     

光漂白对极化聚合物薄膜非线性效应的影响

利用Cerenkov倍频辐射对极化聚合物薄膜在光漂白下二阶非线性效应的变化进行了研究。 实验表明光漂白能破坏有机聚合物中极化分子的取向稳定性,造成其二阶非线性效应衰减。实验测得漂白后交联型材料的二阶倍频信号衰减了28%,而侧链型材料则衰减了75%。     

聚合物复合材料薄膜极化及性能的研究

制取了ＰｂＴｉＯ３纳米微晶与高透明度的聚合物ＰＥＫ－Ｃ组成的复合材料薄膜,从介电性和有效场理论出发,对极化条件的优化进行了研究,通过测量极化后的复合材料的Ｘ－ｒａｙ衍射,得知ＰｂＴｉＯ３微晶的ｃ轴取向度达到６８％,测量了３８０ｎｍ－９００ｎｍ的透过光谱,估算了极化前后光学带隙能量。     

超薄膜厚度对其结构和性能的影响

以流体力学稳定性理论为指导,研究了超薄膜厚度对其结构和性能的影响。指出,适当的膜厚可以消除膜表面的缺陷孔洞,使膜在获得高透水率的同时也具有高的截留性能。     

色散介质中积累二次谐波的发生

对色散介质中平面波的积累二次谐波发生问题进行了研究。给出了形式简捷的积累二次谐波振幅和相位的解析表达式，还给出积累二次谐波发生的临界距离，据本文的分析方法，能很好地理解色散介质中积累二次谐波发生的物理过程。     

活塞聚焦换能器的二次谐波声场

1　引　言　　研究聚焦换能器的非线性声场是非线性声学中受到关注的问题。这是由于聚焦活塞换能器在焦点附近能产生很强的非线性且圆型活塞聚焦换能器由于能有效地提高分辨率而被广泛应用于超声医学诊断及超声显微镜。对于有限振幅的活塞聚焦声场 ,分析时必须同时考虑衍射效应和非线性波型畸变效应 ,因此在数学分析上相当复杂 ,Lucas等人 [1] 在Parabloic近似下 ,导出了活塞聚焦换能器的基波 ,二次谐波积分型式的解 ,尽管这种解的形式是解析的 ,但由于解的形式是多重积分 ,对于实际的声场分析计算不够方便。由于高斯函数的积分具有相对简…     

用二次谐波检测舰船电场的研究

提出一种测量舰船电场的新方法，即用二次谐波方法测量大轴周围磁场，从而确定大轴电流，进而分析由大轴电流带来的舰船电场，理论和实验均表明，该方法结构简单，构思精巧，是检测舰船电场的方法之一。     

电能表试验中奇次谐波和次谐波的频谱分析

对于电能表电流线路中存在的畸变形波、引起误差的情况,为在电能表试验中实现该影响试验项目提出了一种新的方法。该法对试验项目中所施加的试验电流波形进行了频谱分析,为通过试验装置的计算机软件进行检定提供了理论基础。     

薄膜厚度对TGZO透明导电薄膜光电性能的影响

利用直流磁控溅射法,在室温水冷玻璃衬底上成功制备出了可见光透过率高、电阻率低的钛镓共掺杂氧化锌(TG-ZO)透明导电薄膜。X射线衍射和扫描电子显微镜研究结果表明,TGZO薄膜为六角纤锌矿结构的多晶薄膜,且具有c轴择优取向。研究了厚度对TGZO透明导电薄膜电学和光学性能的影响,结果表明厚度对薄膜的光电性能有重要影响。当薄膜厚度为628 nm时,薄膜具有最小电阻率2.01×10-4Ω.cm。所制备薄膜在波长为400~760 nm的可见光中平均透过率都超过了91%,TGZO薄膜可以用作薄膜太阳能电池和液晶显示器的透明电极。     

Effect of a bell-shaped cover in spin coating process on final film thickness

Thin polymer films can be prepared by spin coating with thicknesses ranging from nanometers to micrometers. The film thickness is controlled by concentration of the polymer solution, molar mass of the polymer and spinning speed. The patented GYRSET system for spin coating applications provides a fundamental modification. The bell-shaped cover minimizes air turbulences inside the process chamber; therefore, better uniformity of the layer is produced. This leads to highly reproducible results, uniform coverage, and reliable and uniform material application, in particular at lower spin speeds. We focus on the question how does the GYRSET system change the final film thickness. In particular, we have investigated modifications of the existing spin coat equation for solutions of polystyrene dissolved in toluene using the GYRSET system. In addition, we compare homogeneity of films prepared by open spin coating and GYRSET systems. Received: 9 October 2000 / Reviewed and accepted: 10 October 2000     

Second harmonic generation from a ferroelectric film

We derive an expression for transmittivity (T_SHG) of second harmonic generation (SHG) signals from a ferroelectric (FE) film. Intensities of up and down fields in the medium are investigated in relation to T_SHG. The derivations are made based on undepletion of input fields and nonlinear wave equation derived from the Maxwell equations. We present two cases: film without mirrors and with partial mirrors. Expressions for the newly derived nonlinear susceptibility coefficients of SHG for real crystal symmetry [J. Opt. Soc. Am. B 19 (2002) 2007] are used to get more realistic results. Variations in T_SHG with respect to film thickness are illustrated.     

Probing and modeling of carrier motion in organic devices by optical second harmonic generation

We here report a novel optical second harmonic generation (SHG) measurement that allows an electric field formed in organic solid to be probed. We examined the SHG intensity profile that changes depending on a space charge field caused by carrier injection. Experiments making use of time-resolved SHG technique has revealed dynamic changes of SHG intensity profiles arising from pentacene, and that carrier transport in OFET was diffusion-like. Calculations using drift-diffusion equation well accounted for the visualized carrier motion probed by time-resolved SHG. That is, interface charge propagation process dominates the carrier transport, which is regulated by applied gate-source voltage.     

薄膜厚度对ITO膜结构与性能的影响

本文对所研究的直流磁控溅射法制备的ITO透明导电薄膜,采用X射线衍射技术进行了膜层晶体结构与薄膜厚度关系的分析, 并测量了薄膜电阻率及透光率随薄膜厚度的变化情况.实验结果表明,当控制薄膜厚度达70 nm以上时,可获得结晶性好、电阻率低和透光率高的ITO透明导电薄膜,所镀制的ITO膜电阻率已降到1.8×10^-4 Ωcm,可见光透过率达80%以上.最后还对所镀制的ITO透明导电薄膜的质量指标作了评估.     

Numerical simulation of cascaded third harmonic generation for both phase matched and mismatched schemes

Numerical solutions to the nonlinear coupling-wave equations of second harmonic (SH) and third harmonic (TH) generators are investigated for both phase matched and phase mismatched configurations. For phase mismatched TH generation, several kinds of schemes (the phase mismatch either in second harmonic generation (SHG) or sum-frequency generation (SFG) process) are considered and analyzed. The physical nature corresponding to the different ratios of the coupling coefficients is discussed.     

工艺条件对金刚石膜红外透射率影响的研究

为了优化金刚石沉积工艺,制备高透射率的CVD金刚石薄膜,采用傅里叶红外光谱仪对不同工艺条件下制备的CVD金刚石膜的红外透射率进行了测量,分析了不同工艺条件对金刚石膜红外透射率的影响,获得了最佳沉积参数.结果表明,金刚石膜的红外透射率与工艺条件密切相关,当衬底温度为750℃,碳源体积分数为2%,压强为2.5kPa时沉积的金刚石膜红外透射率最佳.     

磁控溅射膜层厚度均匀性测试

在相对于平面磁控溅射阴极均匀区范围内安放硅片，镀膜后进行膜层厚度测试，然后计算膜层厚度均匀度。结果，片间厚度均匀性为1％～-1．7％；炉间厚度均匀性为3．5％～-2％。     

Theoretical modeling on resonating the second harmonic for ultraviolet laser generation

The resonance of the second harmonic was proposed to improve conversion efficiency in ultraviolet laser. A schematic to generate the fourth harmonic laser with a compound cavity was modeled based on plane-wave approximation. The simulated results show that the mode-matching condition of the multi-mode lasers depends strongly on both frequency-mode spacing and resonator loss. In the case of the same cavity lengths and losses, the tolerance on the optical cavity length should be maintained on tens or hundreds of nanometer scales. Meanwhile, the TEM₀₀ beam can be achieved due to the best mode-matching at resonance and the beam size increases arising from the cavity detune.     

Large enhancement of second harmonic generation in highly cerium doped lead-phosphate glass

The influence of lead and cerium concentration on photoinduced second harmonic generation (SHG) in lead-phosphate glasses has been studied. It has been shown that SHG can be considerably enhanced by increasing of lead and cerium concentration. We also have found that cerium greatly extends the induced nonlinearity lifetime. Physical mechanism of the phenomenon is discussed.