光学薄膜鲁棒设计中膜系误差灵敏度控制

提出了一种基于膜系误差灵敏度控制的鲁棒膜系设计方法,建立了鲁棒膜系设计评价函数在膜层参数误差统计分布下的解析表达式,避免统计样本数目有限性造成的样本均值与总体期望的误差,以及过大数目样本造成的长的计算时间消耗,并通过宽带增透膜、中性分光膜和线性透射率滤光片等多种薄膜的鲁棒设计实验证实了其在膜层参数误差控制上的效果。结果表明：该新型鲁棒膜系设计方法具有内在的快速算法特性,其设计膜系对镀膜中的膜厚监控误差不敏感,对于高质量薄膜的重复制备和批量成品率的提高具有实用价值。     

Hydrogen-induced blistering mechanisms in thin film coatings

We report on the mechanisms of hydrogen-induced blistering of multilayer coatings. Blister formation is a result of highly localized delamination occurring at the two outermost metal-on-silicon interfaces. The number, size, and type of blisters formed varied depending on the composition and ion energy of the incident flux. The results are explained in terms of the multilayer structure being simultaneously susceptible to blistering via two independent mechanisms. A high density of small blisters developed when relatively energetic (several 100 eV) ions were present. Independently, a hydrogenation process that was facilitated by the presence of a small flux of low energy ions (≤ 50 eV) induced a low density of large blisters.     

The third order nonlinear optical characteristics of amorphous vanadium oxide thin film

We studied the nonlinear absorptive characteristics (saturation intensity threshold and effective nonlinear absorption coefficients) and nonlinear refraction in a 50-nm-thick VO _x thin amorphous film prepared by pulsed DC magnetron reactive sputtering. The absorptive and refractive nonlinearities were investigated by pump–probe and Z-scan techniques. The closed-aperture Z-scan results reveal self-defocussing characteristics of the amorphous VO _x thin film for both nanosecond and picosecond pulse durations. Experimental results show that a phase transition does not occur in the range of intensities used for the experiments and the investigated sample can be treated as an amorphous semiconductor structure. The open-aperture Z-scan curves with nanosecond pulses exhibit saturable absorption for all input intensities. On the other hand, the open-aperture Z-scan curves with picosecond pulses exhibit nonlinear absorption/saturable absorption for low/high input intensities, respectively. Saturation intensity thresholds were found to be 15.3 MW/cm² for 4-ns pulse duration and 586 MW/cm² for 65-ps pulse duration.     

基于频率特征的薄膜损伤声学判别方法

利用声学法研究单层氧化硅薄膜在不同激光能量下的损伤情况,建立了激光致薄膜产生的声波采集系统,对其采集到的时域信号进行傅里叶变换,比较和分析薄膜损伤前后声波24~40kHz高频段的曲线,提取频率特征,并提出用曲线相似函数进行薄膜损伤的识别方法。实验数据结果表明,该方法简单易行,可降低环境噪声的影响,既能实现在线检测,又能准确判别薄膜损伤。     

Determination of optical constants and nonlinear optical coefficients of Violet 1-doped polyvinyl alcohol thin film

The optical properties of Violet 1-doped polyvinyl alcohol (PVA) have been investigated using Wemble and Didomenico (WD) method. The optical constants such as refractive index n, the dispersion energy E _d, the oscillation energy E ₀, the lattice dielectric constant \(\varepsilon _{\infty } \), light frequency dielectric constant ε ₀ and the ratio of carrier concentration to the effective mass N/m* have been determined using reflection spectra in the wavelength range 300–900 nm. The single- beam Z-scan technique was used to determine the nonlinear optical properties of Violet 1:polyvinylalcohol (PVA) thin film. The experiments were performed using continuous wave (cw) laser with a wavelength of 635 nm. The calculated nonlinear refractive index of the film, n ₂ = ?2.79×10^?7 cm²/W and nonlinear absorption coefficient, β = 6.31×10^?3 cm /W. Optical limiting characteristics of the dye-doped polymer film was studied. The result reveals that Violet 1 can be a promising material for optical limiting applications.     

Cerium dioxide thin film optical waveguides

Cerium dioxide thin film optical waveguides were fabricated by an RF magnetron sputtering process. The films were deposited on glass substrates and on silicon dioxide layers grown on silicon substrates. Optical loss measurements for the fabricated waveguides are reported. It is seen that the volume losses in the films were fairly high compared with the surface losses.     

Four-layer metal-clad thin film optical waveguides

An investigation of the low order modes supported by an asymmetrical four-layered metal-clad optical waveguide is presented showing the attenuation characteristics and the field profiles. The attenuation and phase constants are examined as functions of both the thickness and refractive index of the buffer layer as well as the mode order. The results for small and large buffer layer thicknesses are discussed in terms of the modes supported by simpler asymmetrical three-layered metal-clad and dielectric-clad waveguides respectively. It is shown that the coupling of the TM polarized modes to the lossy surface plasma wave depends upon the buffer layer thickness, the refractive indices of the buffer layer and dielectric cladding and the mode order. This coupling is very dependent upon the mode order with the TM₀ mode exhibiting far weaker coupling than the higher order TM modes. Methods of controlling the amount of coupling and hence the attenuation of the TM modes are discussed.This work was performed while the author was with the Department of Electrical Engineering, University of Queensland, Brisbane, Australia, 4067.     

Effects of pinhole diameters on beam characteristics for silicon thin film optical inspection

Peak power density stability and beam-wander precision of probe laser are important factors affecting the inspection results in the precision thin film optical measurements. Pinhole is frequently used as a spatial filter in the optical inspection system. In this work, four different diameters of pinhole are investigated experimentally. It is found that pinhole diameter of 0.3 mm is considered to be a promising candidate for mounting in front of probe laser for silicon thin film optical inspection due to better peak power density stability and better beam-wander precision.     

DNA thin film coated optical fiber biosensor

We present a simple but highly sensitive biotinylated DNA double crossover thin film coated fiber optic reflectance biosensor (DTF FORS) for the detection of streptavidin aerosols as a building block towards sensing bio-aerosols. The DNA double crossover lattice with biotin was dropped on the polymer optical fiber end face to prepare DNA Thin Film. The streptavidin aerosols were prepared using conventional aerosol technology. The DTF FORS response to streptavidin aerosol was few seconds and the sensor repeatability for air and streptavidin aerosol was found to be excellent. The presented FORS sensing approach, where the film can be changed on the end face of the optical fiber, is expected to detect atmospheric bio-aerosols with great sensitivity and effective specificity.     

光学薄膜保护封闭漆

用普通光学镀膜机蒸镀的光学膜,如果暴露在大气中一经受潮,镀膜材料的折射率发生变化,其结果会令光学薄膜的中心波长产生漂移,因而影响薄膜的光学特性。如蒸镀软膜,受潮后漂移则更为严重。另外软膜表面强度差,易擦伤和脱膜。封闭漆既能有效防潮,又能改善光学薄膜表面强度,而且不影响光学薄膜的光学特性。     

All optical switching in henna thin film

The optical nonlinearity in henna (Lawson (2- hydroxyl-1,4 naphthoquinone) film was utilized to demonstrate all optical switching. The nonlinear absorption of the henna film was calculated by measuring the transmission of the laser beam (λ = 488 nm) as a function of incident light intensities. The observed nonlinear absorption is attributed to a two-photon absorption process. The pump and probe technique was used to demonstrate all optical switching. The switching characteristics can be utilized to generate all-optical logic gates such as simple inverter switches (NOT) NOR, AND NAND logic functions.     

Determination of the optical constants and thickness of a thin slightly absorbing film by ellipsometric measurement

On the basis of an analysis of the properties of space constructed in coordinates of the ellipsometric angles and and the thicknessd ₁ of a thin slightly absorbing film, a graphical method of determining its index of refraction, index of absorption and thickness is proposed and discussed. From the two ellipsometric measurements, either for two different angles of incidence or for two different surrounding media, it is in principle possible to determine the chosen parameters characterizing the thin slightly absorbing film. The graphical method, however, seems to be less accurate and very laborious. The calculation is therefore proposed for an automatic computer. The ellipsometric measurements were carried out on a SAAB computer, according to a program elaborated in Algol. The results obtained and the values computed for the optical constants and the thickness of the thin slightly absorbing film are in good agreement with those found independently.     

记录薄膜Te—In—Sb光学性质的研究

采用高频溅射方法制成Te-In-Sb系统的非晶态薄膜.系统的研究了不同组分薄膜的透射、反射谱,及其在结晶过程中的变化.用透射电镜研究了Te-In-Sb薄膜的结构和晶化过程.分析了组分对薄膜的吸收系数、介电常数、光学能隙等光学性质的影响.并由此综合评价了Te-In—Sb系统中比较适合作为光盘介质的组成.     

薄膜光学锥形光栅的制备与光学特性分析

为了在光学薄膜中引入连续轮廓的微结构,综合利用薄膜的干涉效应与微结构的折反射、衍射效应,提出一种薄膜光学微结构的制备工艺。基于时域有限差分方法设计了具有可见光波段减反射特性的薄膜光学锥形光栅;采用单点金刚石车削技术,结合纳米压印与电感耦合等离子体刻蚀技术,在SiN_x薄膜中制备出高1.6 μm,周期4.1 μm的锥形光栅;在可见光波段,SiN_x薄膜光学锥形光栅的平均反射率为5.7%,反射率的实验检测结果与仿真计算结果达到很高的一致性;当入射光角度在30°以内,薄膜光学锥形光栅的减反特性表现出对光波入射角度的不敏感性。该制备工艺突破了单点金刚石车削技术的材料局限,将连续轮廓的微结构的直接形成工艺拓展至介质薄膜当中,实现了宽光谱、宽入射角度的减反射。     

Quantum dynamics in a thin film. II. Stationary states

The spectrum of quantum waveguides simulating thin toroidal tubes and thin spherical surfaces is investigated. Asymptotic formulas are obtained and a geometric classification using the so-called Reeb graphs is carried out.     

Effect of an optical negative index thin film on optical bistability

We investigate nonlinear transmission in a layered structure consisting of a slab of positive index material with Kerr-type nonlinearity and a subwavelength layer of linear negative index material (NIM) sandwiched between semi-infinite linear dielectrics. We find that a thin layer of NIM leads to significant changes in the hysteresis width when the nonlinear slab is illuminated at an angle near that of total internal reflection. Unidirectional diodelike transmission with enhanced operational range is demonstrated. These results may be useful for NIMs characterization and for designing novel NIMs-based devices.     

光学薄膜界面互相关特性的确定

本文实验测量了光学薄膜的散射波场分布,根据多层光学薄膜的矢量散射理论,确定了膜层界面的互相关特性.当空间频率较低时,对于膜层层数较少的膜系,膜堆内的各界面是完全相关的;若空间频率较高,则逐渐趋于部分相关模型.实验指出,膜层界面的互相关特性亦与所采用的蒸发技术有关.     

Nonlinear optical properties of a self-organized dye thin film

A self-organized thin film of a cyanine dye is fabricated by the spin-coating technique and is characterized by ultraviolet-visible spectroscopy, infrared (IR) spectroscopy, small-angle X-ray diffraction, ellipsometer,and atomic force microscopy (AFM). The nonlinear optical properties of the thin films are investigated by degenerate four wave mixing (DFWM) technique. The cyanine dye thin film sample exhibits high optical nonlinearities (χ(3) = 2.55 × 10-12 esu), and the mechanism is analyzed by the exciton coupling theory.     

薄膜材料光学参量的测量

介绍了薄膜材料光学参量测量实验的原理和方法以及对GaN膜的测量结果。     

Evaluation of electrical and optical characteristics of ZnO/CdS/CIS thin film solar cell

In this study, device modeling and simulation are conducted to explain the effects of each layer thickness and temperature on the performance of ZnO/CdS/CIS thin film solar cells. Also, the thicknesses of the CIS and CdS absorber layers are considered in this work theoretically and experimentally. The calculations of solar cell performances are based on the solutions of the well-known three coupling equations: the continuity equation for holes and electrons and the Poisson equation. Our simulated results show that the efficiency increases by reducing the CdS thickness. Increasing the CIS thickness can increase the efficiency but it needs more materials. The efficiency is more than 19% for a CIS layer with a thickness of 2 μm. CIS nanoparticles are prepared via the polyol route and purified through centrifugation and precipitation processes.Then nanoparticles are dispersed to obtain stable inks that could be directly used for thin-film deposition via spin coating.We also obtain x-ray diffraction(XRD) peak intensities and absorption spectra for CIS experimentally. Finally, absorption spectra for the CdS window layer in several deposition times are investigated experimentally.