高三阶光学非线性Cd/CdS-SiO2复合薄膜的电化学–溶胶凝胶制备及表征

以硝酸镉、硫脲和正硅酸乙酯为前驱体, 采用电化学-溶胶凝胶法, 以ITO玻璃为基底制备了透明薄膜。扫描电子显微镜(SEM)表征表明薄膜为纳米束结构。X射线能谱(EDX)表征表明薄膜由Si、O、Cd、S元素组成, Cd/S(原子比)＞1。EDX表征结合循环伏安(CV)实验确定薄膜为Cd/CdS-SiO₂复合薄膜。Z扫描表征表明, 薄膜在1064 nm处表现出自散焦特性的非线性折射效应和饱和吸收特性的非线性吸收特性。薄膜的三阶非线性极化率(χ(3))较高, 达到了1.18×10^-14~1.39×10^-13 (m/V)², 表明薄膜具有优良的三阶光学非线性。分析认为薄膜中CdS的含量对薄膜的光学性非线性起主要作用。     

含Ag量子点钠硼硅玻璃的三阶非线性光学性质

以正硅酸乙酯、硼酸、金属钠为前驱体采用溶胶-凝胶法合成含Ag量子点的钠硼硅玻璃。X射线粉末衍射 (XRD) 分析Ag量子点具有立方相。通过透射电子显微镜 (TEM) 和高分辨透射电子显微镜 (HRTEM) 测定量子点的尺寸和分布, 结果显示在玻璃中量子点呈规则的球形, 并且尺寸在5~13 nm之间。紫外-可见(UV-Vis)吸收光谱仪得到Ag量子点的表面等离子体共振吸收峰大约在406 nm附近; 利用飞秒Z-scan 技术在800 nm波长处用飞秒钛宝石激光辐照对Ag量子点玻璃的非线性光学性质进行研究, 该玻璃的非线性折射率γ、非线性吸收系数β和三阶非线性极化率χ⁽³⁾分别为 –1.72×10^-17 m²/W、9.96×10^-11 m/W、1.01×10^-11 esu。     

二氧化钛薄膜的三阶非线性光学特性

采用脉冲激光沉积技术在熔石英基片上制备了c轴取向的锐钛矿相TiO₂薄膜.通过X射线衍射和原子力显微镜对薄膜的结构、结晶性和表面特性进行了表征.通过透射光谱计算得到TiO₂薄膜折射率约为2.1,光学带隙约为3.18eV.结合飞秒激光和Z扫描方法测量了薄膜的超快非线性光学特性,结果表明：锐钛矿TiO₂薄膜具有负的非线性吸收系数和负的非线性折射率,其大小分别为-6.2×10^-11m/W和-6.32×10^-17m²/W,对应的三阶非线性极化率的实部和虚部分别为-7.1×10^-11esu和-4.42×10^-12esu.并计算薄膜的优值比T=βλ/n₂≈0.8,表明锐钛矿相的TiO₂在非线性光学器件方面具有潜在的应用前景.     

银复合的Ge-In-S-CsI硫系玻璃的非线性光学性能研究

通过真空熔融淬冷法制备了银复合的70GeS₂-20In₂S₃-10CsI硫系玻璃样品, 利用Z-扫描技术研究了玻璃样品在800 nm处三阶非线性光学性质, 发现引入Ag可提高其折射率n和非线性折射率γ, n从2.204增加至2.4087, γ从23.3×10^-18 m²/W增加到30.5×10^-18 m²/W, 此外非线性响应时间从70 fs增加到79 fs。热处理对玻璃的非线性光学性能的影响研究显示, 热处理后样品的γ增加至44.3×10^-18 m²/W, 是As₂Se₃玻璃的两倍多。发现析晶后带隙变小(吸收边红移)导致非线性吸收系数β减小, 使得样品的品质因子提高至3.3。Ag复合的硫系玻璃及玻璃陶瓷非线性折射率大、品质因子高、非线性响应快, 有望用于全关开关等各类非线性光学器件中。     

纳米硅镶嵌氮化硅薄膜的制备及非线性光学性质研究

采用射频磁控反应溅射法结合热退火处理技术制备纳米硅镶嵌氮化硅(nc-Si/SiNx)复合薄膜.通过X射线能谱(EDS)、红外光谱(IR)、X射线衍射(XRD)及紫外-可见吸收光谱(UV-vis)的测定,对薄膜进行了组分、键合状态、结构及光学带隙的表征.采用皮秒激光运用单光束Z扫描技术开展了对该复合薄膜的非线性光学性质的研究,测得其三阶非线性折射率系数和非线性光吸收系数分别为10-8esu和10-8m/W量级,并将薄膜这种三阶光学非线性增强的原因归因于量子限域效应.     

介孔Au/ZrO2复合薄膜的制备及其三阶非线性光学性能（英文）

以尿素为沉淀剂,通过沉积沉淀的方法,制备了高分散的金纳米颗粒负载的介孔氧化锆薄膜;以1064 nm激光为入射光束,通过Z扫描实验测试了复合薄膜的非线性光学折射和吸收,并计算了复合薄膜的非共振三阶非线性光学极化率(~10-10esu),金纳米颗粒的高分散性和氧化锆薄膜衬底的高线性折射率使复合薄膜显示了增强的三阶非线性极化率.     

溶剂对FTO薄膜的结构和光电性能的影响

采用喷雾热解法(SPD),分别使用甲醇、乙醇、异丙醇、正丁醇和去离子水作为溶剂制备F掺杂的SnO₂(FTO)透明导电薄膜,使用X射线衍射仪、扫描电子显微镜、四点探针电阻仪、霍尔效应仪和紫外可见分光光度计等手段对薄膜进行测试和表征,研究了溶剂对FTO薄膜结构、形貌和光电性能的影响,研究了溶剂对FTO薄膜结构与光电性能的影响。结果表明：FTO薄膜具有四方相金红石结构;使用不同溶剂制备的薄膜,其表面形貌和颗粒尺寸明显不同;使用甲醇为溶剂制备的FTO薄膜呈现饱满的金字塔状,晶粒尺寸均匀,结构致密,具有最佳的综合光学和电学性能,其电阻率可达4.43×10^-4 Ω·cm,载流子浓度为9.922×10²⁰ cm^-3,品质因数为1.646×10^-2 Ω^-1,可见光区透射比均大于75%。     

界面聚合-原位制备聚吡咯/CdS纳米复合材料及其非线性光学性能

为了提高聚吡咯(PPy)的光电性能,通过界面聚合-原位法制备了PPy/Cd S复合薄膜材料,用红外光谱、X射线衍射、扫描电镜、热重分析等方法对产物进行了表征。制备的PPy/Cd S薄膜结构平整,投料比对Cd S纳米棒尺度有明显影响。用紫外吸收、Z-扫描技术初步研究了PPy/Cd S的非线性光学(NLO)性质。PPy/Cd S具有明显的饱和吸收和非线性负折射。PPy/Cd S(摩尔比10∶1)薄膜的非线性折射率是PPy薄膜的2.4倍,三阶非线性极化率是PPy的2.1倍,说明PPy/Cd S薄膜具有良好的三阶NLO性能。该复合材料在光限幅等光电领域具有潜在的应用价值。     

毫米波功率计量标准器芯片的研制

针对毫米波WR-6波段功率标准器核心芯片需求,设计了芯片整体结构,研究了结构中各层的微加工工艺,制备了温度传感用Pt薄膜,在250 ℃退火后,100 nm Pt薄膜的电阻温度系数(TCR)达到2.4×10^-3/K,相对稳定度为2.4×10^-6。安装在毫米波功率标准器上的芯片对110～170 GHz的反射率低于-23 dB。直流功率灵敏度为0.83 mΩ/mW。     

MnO2纳米棒-还原石墨烯复合修饰玻碳电极用于苋菜红的检测

利用电化学还原法制备MnO₂纳米棒-还原石墨烯复合修饰电极（MnO₂ NRs-ErGO/GCE）用于苋菜红的检测。采用SEM和XRD分别对修饰电极材料进行微观形貌和成分结构表征。通过循环伏安法考察了苋菜红在裸电极、ErGO/GCE和MnO₂ NRs-ErGO/GCE上的电化学行为,并对测定条件如pH值、富集电位、富集时间进行了优化。结果表明,MnO₂ NRs-ErGO增大了GCE电化学活性面积,提高了苋菜红的电化学氧化响应。在最优的检测条件下,MnO₂ NRs-ErGO/GCE线性扫描伏安法检测苋菜红线性范围为2.0×10^-8~1.0×10^-5 mol/L和1.0×10^-5~4.0×10^-4 mol/L,检测限为1.0×10^-8 mol/L。MnO₂ NRs-ErGO/GCE用于真实饮料样品检测,获得满意结果。     

Rh:BaTiO3 thin films with large nonlinear optical properties

We report the fabrication and the nonlinear optical properties of Rh-doped BaTiO3 thin films. The films were deposited on SrTiO3 (100) substrates by pulsed-laser deposition. The deposited Rh:BaTiO3 thin films were single phase and c-axis orientation investigated by x-ray diffraction. The films exhibited large nonlinear optical effects, which were determined using Z-scan technique at a wavelength of 532 nm with a laser duration of 10 ns. The real and imaginary parts of the third-order nonlinear susceptibility chi (3) were 5.71 x 10(-7) esu and 9.59 x 10(-8) esu, respectively. The value of Re chi (3) of Rh:BaTiO3 films is much larger than those of several representative nonlinear optical thin films. The results show that Rh:BaTiO3 thin films have great potential applications for nonlinear optical devices.     

Influence of electron beam irradiation on nonlinear optical properties of Al doped ZnO thin films for optoelectronic device applications in the cw laser regime

We present the studies on third-order nonlinear optical properties of Al doped ZnO thin films irradiated with electron beam at different dose rate. Al doped ZnO thin films were deposited on a glass substrate by spray pyrolysis deposition technique. The thin films were irradiated using the 8 MeV electron beam from microtron ranging from 1  kG y to 5  kG y. Nonlinear optical studies were carried out by employing the single beam Z-scan technique to determine the sign and magnitude of absorptive and refractive nonlinearities of the irradiated thin films. Continuous wave He–Ne laser operating at 633 nm was used as source of excitation. The open aperture Z-scan measurements indicated the sample displays reverse saturable absorption (RSA) process. The negative sign of the nonlinear refractive index n₂ was noted from the closed aperture Z-scan measurements indicates, the films exhibit self-defocusing property due to thermal nonlinearity. The third-order nonlinear optical susceptibility χ(3) varies from 8.17 × 10⁻⁵ esu to 1.39 × 10⁻³ esu with increase in electron beam irradiation. The present study reveals that the irradiation of electron beam leads to significant changes in the third-order optical nonlinearity. Al doped ZnO displays good optical power handling capability with optical clamping of about ∼5 mW. The irradiation study endorses that the Al doped ZnO under investigation is a promising candidate photonic device applications such as all-optical power limiting.     

Linear and nonlinear optical properties of RF sputtered (Pb,La)(Zr,Ti)O<Subscript>3</Subscript> ferroelectric thin films

Linear and nonlinear optical properties of (Pb,La)(Zr,Ti)O₃ (PLZT) ferroelectric thin films were presented in this paper. The PLZT ferroelectric thin films have been in situ grown on quartz substrates by radio-frequency (RF) magnetron sputtering at 650 °C. Their crystalline structure and surface morphologies were examined by X-ray diffraction and atomic force microscopy, respectively. It can be found that the PLZT thin films exhibit well-crystallized perovskite structure and good surface morphology. The fundamental optical constants (the band gap energy, linear refractive index, and linear absorption coefficient) were obtained through the optical transmittance measurements. A Z-scan technique was used to investigate the optical nonlinearity of the PLZT thin films on quartz substrates. The films display the strong third-order nonlinear optical effect. A large and negative nonlinear refractive index n ₂ is determined to be 1.21 × 10⁻⁶ esu for the PLZT thin films. All results show that the PLZT ferroelectric thin films have potential applications in optical limiting, switching, and modulated-type optical devices.     

Nonlinear optical investigations on Al doping ratio in ZnO thin film under pulsed Nd:YAG laser irradiation

In the present study, it has been reported on the effect of Al doping on linear and nonlinear optical properties of ZnO thin films synthesized by spray pyrolysis method. The structural properties of ZnO thin films with different Al doping levels (0–4 wt%) were analyzed using X-ray diffraction (XRD). The results obtained from XRD analysis indicated that the grain size decreased as the Al doping value increased. The UV–Vis diffused refraction spectroscopy was used for calculation of band gap. The optical band gap of Al-doped ZnO (AZO) thin films is increased from 3.26 to 3.31 eV with increasing the Al content from 0 to 4 wt%. The measurements of nonlinear optical properties of AZO thin films have been performed using a nanosecond Nd:YAG pulse laser at 532 nm by the Z-scan technique. The undoped ZnO thin film exhibits reverse saturation absorption (RSA) whereas the AZO thin films exhibit saturation absorption (SA) that shows RSA to SA process with adding Al to ZnO structure under laser irradiation. On the other hand, all the films showed a self-defocusing phenomenon because the photons of laser stay on below the absorption edge of the ZnO and AZO films. The third-order nonlinear optical susceptibility, χ⁽³⁾, of AZO thin films, was varied from of the order of 10^?5–10^?4 esu. The results suggest that AZO thin films may be promising candidates for nonlinear optical applications.     

The inherent optical nonlinearities of thin silver films

Thin Ag films with the thickness of 80 Å were prepared by pulsed laser deposition technique. The films were grown on MgO(1 0 0) substrates under the nitrogen pressure of 5.0 Pa at room temperature. The surface images of the films were observed by atomic force microscopy. The linear optical properties of the films were studied in the wavelength range of 300–800 nm. The inherent third-order nonlinear optical responses coming from the silver material itself were determined by z-scan method at the wavelength of 532 nm with laser duration of 10 ns. The significant optical nonlinearities of the pure thin Ag films were determined to have the real and imaginary parts of the third-order nonlinear optical susceptibility (χ⁽³⁾) as 2.49 × 10⁻⁸ and 7.16 × 10⁻⁹ esu, respectively. The obtained χ⁽³⁾ value of Ag films was about one order of magnitude larger than that of Ag colloids.     

Structural,optical and magnetic properties of Ba and Ni doped CdS thin films prepared by spray pyrolysis method

Pure, Barium and Nickel doped cadmium sulphide (CdS) thin films have been coated on glass substrates at 400?°C by spray pyrolysis technique. The prepared CdS and doped CdS thin films were analysed by various measurements such as X-ray diffraction (XRD), SEM, optical and Vibrating Sample Magnetometer (VSM). X-ray diffraction measurements show that the coated pure, Ba and Ni-doped CdS thin films belong to the cubic crystal structure with orientation preferentially along (111) direction. The average crystallite size of pure, Ba and Ni doped CdS thin films were determined as 31, 33 and 45 nm, respectively. The average dislocation density (δ) and stacking fault (SF) of pure, Ba and Ni doped CdS thin films were also determined. The surface morphology and elemental analysis of the thin films were determined by scanning electron microscopy and energy dispersive X-ray spectrum (SEM with EDAX). It is observed that the optical energy bandgap has been decreased from 2.43 to 2.1 eV due to the doping Ba. The luminescence spectrum shows a strong emission peak at 517 nm in the case of pure CdS thin film and a meager red shift has been observed due to the doping. VSM studies were employed to study the magnetic behaviour of Ba and Ni doped CdS thin films.     

WO3电致变色薄膜制备过程中光学膜厚测量监控技术的研究

采用真空电子束蒸发方法制备WO3电致变色薄膜过程中，利用极值法光学膜厚测量技术监控薄膜的光学特性，对不同光学膜厚的WO3薄膜的原始态、着色态和退色态的光谱特性进行了对比分析。测试采用二电极恒电压方法，用分光光度计实时测量透过率的变化。结果证明以ITO玻璃作为比较片，极值法监控薄膜光学膜厚，当反射率达到第一极小值，即透过率达到第一极大值时，WO3薄膜得到最好的综合电致变色特性。     

Optical transitions in laser-evaporated thin CuInSe2 films

The optical absorption coefficients of highly oriented laser-evaporated thin films were determined from the measured reflectance R(λ) and transmittance T(λ) in the wavelength range 400–1700 nm. The optical absorption spectrum of CuInSe₂ thin films shows three energy gaps, which are associated with the fundamental edge and valence band splitting by the tetragonal crystal-field and spin-orbit effects, and four optical transitions from the copper d levels to the conduction bands.     

Gold nanoparticles incorporated mesoporous silica thin films of varied gold contents and their well-tuned third-order optical nonlinearities

Gold nanoparticles (NPs) incorporated mesoporous silica thin films (MSTFs) of varied gold contents from 4.64 to 29.15 wt.% were synthesized through a refined chemical modification to the mesopore surface using different amounts of silane with amino end group. The microstructures of the composite thin films were characterized and the off-resonant third-order optical nonlinearities of the composite thin films were investigated by Z-scan technique at 1064 nm. The resultant composite thin films showed increased third-order optical nonlinear susceptibility (χ⁽³⁾) from 4.26 × 10⁻¹¹ to 9.24 × 10⁻¹⁰ esu at increased gold contents. The dependence of χ⁽³⁾ on gold content have been discussed, which can be described by an exponent function y = y₀ + Ae^−x/t when the gold contents of the composite thin films were below 30 wt.%.