bluuebunny/crossref_metadata_2025 huggingface dataset:
Induced Stresses to Optical Substrates Due to High Energy HR Thin Film Coatings
Authors: VanKerkhove Steven , Smith Douglas
Published: February 2023

High Reflecting (HR) mirrors for the University of Rochester's upgrade to the Omega laser must withstand fluences of up to 3 joules/cm2 at a wavelength of 1054nm1 and reflect 99.5% of the incident energy at both S and P polarization's. A coating multilayer design of Ta2O5/SiO2 on a Pyrex substrate was developed to meet these requirements. The overall wavefront error budget for the Omega Upgrade Laser allocated a surface figure tolerance for these HR mirror components of 1/10 wave at 1054nm. During early production the induced stress due to this HR mirror coating caused deflections of Omega mirror substrates to exceed this tolerance. Solutions to control thin film stress were found for this problem.
Fluorescence of Ta2O5 thin films doped by keV Er implantation
Authors: Rigneault H. , Flory F. , Monneret S. , Berthier D. , Roux L.
Published: February 2023

Optical planar waveguides doped with rare-earth ions offer numerous attractive features for use as amplifiers or lasers in optical communications. Erbium is of particular interest because of its intra-4f transition with a wavelength emission around 1.54µm, coinciding with the low-loss window of standard optical telecommunications silica fiber. In this paper, we report optical properties (refractive index, extinction coefficient, losses on guided propagation) and fluorescence of Er ions implanted into tantalum pentoxide (Ta2O5) planar waveguides made by Ion Plating.
Observations of morphology for homogeneous and inhomogeneous titanium dioxide films deposited by ion assisted deposition method
Authors: Ogura Shigetaro , Takagi Itaru , Kikuchi Kazuo
Published: February 2023

In the previous paper1), we reported the technique to obtain homogeneous and particularly both of positively and negatively inhomogeneous films of TiO2 from the starting material of Ti3O5 by ion assisted deposition method. The degree of the inhomogeneity obtained by this method is shown to be about 0.5, and this value is extraordinarily large. To establish the stable inhomogeneous films of TiO2, including the dynamic behaviour of optical properties of the inhomogeneous films, it is vital to analyse the surface and cross-sectional structures of these films. The structure models, possible to explain these dynamic behaviour, have been proposed and examined1,4). Recent tendency for mass production of optical thin film systems is to adopt ion assisted deposition(IAD) or ion plating(IP) to exclude porosity, which is inherently occouring within the films during deposition, to avoid additional dynamic change caused by the sorption of water vapor to the porosity. In this paper we will observe the surface topology by ultra high resolution scanning electron microscope(UHR-SEM) and the non-contact surface profilometer. It is also the purpose to check the cross-sectional structure of the films, and here we have tried to analyse and compare those of the homogeneous and both of the positively and the negatively inhomogeneous TiO2 films by UHR-SEM.
Comparative study of TiO2-MgF2 composite films prepared by electron-beam coevaporation and reactive ion-assisted coevaporation
Authors: Tsai Rung-Ywan , Hua Mu-Yi
Published: February 2023

MgF2 and TiO2 are the most common used low and high refractive-index coating materials, respectively, for optical applications. However, the characteristics of MgF2 and TiO2 films depend on the fabrication methods. MgF2 and TiO2 thin films deposited by conventional thermal evaporation processes at an ambient temperature typically have inferior optical, structural, mechanical, and chemical properties compared with the bulk materials, which is attributed to the moisture absorption due to the columnar structure and low packing density. Thess problems can be remedied by raising the substrate temperatures or by high energy ion bombardment. It has been shown that TiO2-MgF2 composite films prepared by reactive ion-assisted coevaporation (IAC) do offer the potential of improving performance by optimizing their properties.1 The aim of this paper is to study the optical, structural, and mechanical properties of TiO2-MgF2 composite films prepared by electron-beam coevaporation (EBC) at the substrate temperature of 280 °C. The comparison of the properties on these films with those obtained by reactive IAC is also presented.
Effects of Surface Compression Strengthening on Properties of Sputter-Deposited ITO Films on Automobile Safety Glass
Authors: Huang Daoyang , Ho Fang C. , Parsons Robert R.
Published: February 2023

Indium tin oxide (ITO) films are capable of reflecting infrared lights and are highly transparent. In addition, ITO films have high conductivity and are very stable to the environment. Because of these characteristics, they can be used as heat-resistant and transparent conductive coatings on automobile glass for preventing the solar heat penetration in the summer and for de-fogging and de-icing in the winter (1-3). In order to prevent injuries, automobile safety glass need to be strengthened. However, very little was reported in the literature regarding the effects of strengthening on properties of ITO films on automobile safety glass. Hence, in the following sections we report our study on this important technology issue.
Characterization of composite CaF2-TiO2 films prepared by e-beam coevaporation
Authors: Shiau Sen-Chrong , Tsai Rung-Ywan , Ho F. C.
Published: February 2023

From previous studies on the characterization of MgF2 thin films co deposited with TiO2 films and with ZnSe films (1, 2), we have found that for both types of mixed films, the film hardness was increased, the adhesion to substrates improved, and most interesting, a controllable variation in refractive indices was obtained.
Sol-gel Deposited Electrochromic Coatings
Authors: Ozer Nilgun , Lampert Carl M.
Published: February 2023

Electrochromic devices have increasing application in display devices, switchable mirrors and smart windows. A variety of vacuum deposition technologies have been used to make electrochromic devices. The sol-gel process offers an alternative approach to the synthesis of optical quality and low cost electrochromic device layers. This study summarizes the developments in sol-gel deposited electrochromic films. The sol-gel process involves the formation of oxide networks upon hydrolysis-condensation of alkoxide precursors. In this study we cover the sol-gel deposited oxides of WO3, V2O5, TiO2, Nb2O5, and NiOx.
Antireflection and High reflection coatings for excimer laser applications
Authors: Novopashin V.V. , Levchuk E.A. , Kolodny G. Ya. , Tuyrin V.S.
Published: February 2023

During the last years a grate interest arises to UV-lasers. This
interest due to their applications in various filds of electronics and
medecine. In this paper we present the results of fabricating
dielectric films with high resistance to laser radiation at 193, 248,
266, 355 nm.[1,2]
Quasi–symmetric Electrochromic Device with two kinds of Amorphous Tungsten Oxide Films
Authors: Yong-hong Ye , Pei-fu Gu , Xu Liu , Jing-fa Tang , Hua Guo , Yue-guang Zhang
Published: February 2023

Thin amorphous films of tungsten oxide form the basic for a passive electrichromic device, in which a film is colored blue by simultanous injection of ions and electrons. Tungsten oxide films are usually used as a electrochromic(EC) layer. In this paper, two kinds of amorphous tungsten oxide films are made by thermal evaporation. One shows high color efficiency, and is good for EC layer use. The other shows low color efficiency but high ion injected charge, and is good for counter–electrode(CE), A qusi–symmetry electrochromic device is made by using this two different amorphous tungsten oxide films.
Efficient Oblique Reflective Filters For A 254 nm Imaging System
Authors: Lalezari R. , Gallant R.C. , Everett G. J. , Kriewaldt M. A.
Published: February 2023

An ultraviolet imaging system with a unique and highly efficient spectral filter is described. This filter was designed to have high throughput at the 254 nm wavelength emitted by a low pressure mercury arc lamp and to reject all residual radiation from the lamp up to the cutoff wavelength of the CCD camera used in the particular system (1200 nm).
Tilted Bilayer Membranes as Wave Retardation Plates
Authors: Azzam R. M. A. , Mahmoud F. A.
Published: February 2023

Coherent multiple-beam interference in a tilted parallel-plane thin dielectic slab leads to a differential transmission phase shift Δt between the p and s linear polarizations, hence such a slab (of an optically isotropic material) acts as the simplest possible nondeviating retardation plate1. However, a fundamental limitation of this basic device is that quarter-wave retardation (QWR), i.e., Δt = 90°, is not attainable using a single uncoated slab. Here it is shown that this limitation is lifted if the slab is coated with a thin film of transparent material of different refractive index. All of the reflection and transmission properties of such transparent bilayer membranes, or pellicles, are studied in detail. These membrane retarders are better suited for the IR and require operation at high angles of incidence. Some of the material systems tested for this application include BaF2 and ThF4-coated Ge and a-Si:H layers. A unique design produces dual-QWR in transmission and reflection and uses a BaF2-a-Si:H membrane at 10.6 μm wavelength and 82° angle of incidence. It exhibits reasonable tolerance to small errors or shifts of film thicknesses, angle of incidence, and wavelength.
Infrared Filters and Dichroics for the Advanced Along Track Scanning Radiometer (AATSR)
Authors: Hunneman R. , Hawkins G.J.
Published: February 2023

This paper describes the design and manufacture of the band defining filters and dichroic beamsplitter for the 11 and 12pm infrared channels of the AATSR. The AATSR instrument which is to fly on Envisat-1 polar platform is an improved version of the very successful ATSR-1 flown on Earth Resources Satellite 1 (ERS-1) and its successor ATSR-2 to shortly be launched on ERS-2. The infrared channels are used for the measurement of sea surface temperatures 1 with an accuracy of better than 0.5°C.
Polarization Selective Beamsplitter
Authors: Peifu Gu , Xu Liu , Haifeng Li , Zhidong Zheng , Lanfen Liu , Jinfa Tang
Published: February 2023

The function of the polarization selective beam splitters used for full color display involves two aspects: polarizing light radiation and separating light beam into three primary colors. The properties of these beamspliters have great influence on the brightness, contrast and color distortion of the display system.
Influence of Oxygen on Titanium Oxides Films by Ion Beam Sputter Deposition
Authors: Lee Cheng-Chung , Shen Chan-Han , Hsu Jin-Cherng
Published: February 2023

Titanium oxides were deposited by ion beam sputtering using a Kaufman-type ion source1,2. A beam of argon ions bombarded on a pure titanium target (99.995%) at incident angle 48° from normal. Oxygen gas was fed near the substrate, and its pressure was measured by residual gas analyzer (RGA). The influence of oxygen on titanium oxides films were investigated. The thickness of films were measured by using Dektak surface profiler.
Optical Monitoring of Silver-based Transparent Heat Mirrors
Authors: Lee Cheng-Chung , Chen Shang-Hui , Jaing Cheng-chung
Published: February 2023

We have designed metal-dielectric heat mirrors by using admittance diagram1-2. We find from the admittance diagram that a low loss metal film is necessary in order to have high transmittance for visible light and a high refractive index film is need in order to have high reflectance in IR. We chose silver as the metal and TiO2 as the dielectric.
Sol-Gel Processing of colloid-based optical coatings
Authors: Floch Hervé G. , Belleville Philippe F.
Published: February 2023

It is well established by manufacturers and users that optical coatings are generally prepared by the well known Physical Vapor Deposition (PVD) technology. In the authors' opinion sol-gel technology is an effective and competitive alternative. The aim of this paper is to emphasize on the sol-gel thin film work carried out at Centre d’Études de Limeil-Valenton (CEL-V) and concerning the technology for high power lasers. We will briefly discuss the chemistry of the sol-gel process, the production of optical coatings and the related deposition techniques. Finally, the paper describes the preparation and performance of sol-gel optical coatings we have developed to fulfill the requirements of a future 2-MJ/500-TW (351-nm) pulsed Nd:glass laser. This powerful laser is to be used for our national Inertial Confinement Fusion (ICF) program, to demonstrate at the laboratory scale, ignition of deuterium-tritium fusion fuel. Moreover, the aim of this article is, hopefully, to provide a convincing argument that coatings and particularly optical coatings, are some of the useful products available from sol-gel technology, and that exciting developments in other areas are almost certain to emerge within the coming decade.
Modal Contours For Anisotropic Thin Film Waveguides
Authors: Hodgkinson Ian , Kassam Samer , Hazel Judith , Cloughley Sarah , Wu Qi hong
Published: February 2023

The planar optical waveguiding method which is used extensively for the measurement of the refractive index of isotropic thin films has also been applied to the determination of the three principal refractive indices n1, n2, n3 of anisotropic films.1 As shown in Fig. 1, a prism is used to couple a laser beam into a mode of the film. Scatter in the film provides a mechanism for excitation of neighbouring modes, and the net result is an m-line display as illustrated in Fig. 1(left). The characteristic (Snell’s law) value β = n sin θ is measured for several modes and the principal indices can be determined by matching calculated and experimental modal patterns.
The Application of Nematic Liquid Crystal Interference to Material Science
Authors: Tomilin M.G.
Published: February 2023

The thin layers of oriented nematic liquid Crystal (NLC) applied to an optical quality surface of different materials as a free interference coating, may visualize through polarizing microscope the microrelief or structure defects on the surfaces due to local deformation of coating with high value of optical anisotropy. Nematic interference layers also allow to visualize the distribution of low power electric or magnetic fields upon the surfaces non-observed through optical microscope [1]. These properties are based on physical parameters of NLC molecules which spontaneously reorient locally in unhomogeneous defect zones or external physical fields distributions. On this basis a new universal nondestructive technique to study surface characteristics was developed
NIR- spectroscopy for monitoring water permeability of optical coatings on plastics
Authors: Schulz U. , Kaiser N.
Published: February 2023

The use of plastics for optical applications is limited by physical properties of organic polymers in many cases. Besides the problem of bad scratch resistance, the most plastics tend to absorb and desorb substantial amounts of moisture. Water exchange of the bulk polymer accelerates surface degradation and can destroy the optical performance [1-2]. Considering this, optical coatings on plastics, including those for improving scratch resistance, should reduce water absorption, too.
Color Video Analysis for Microscopic Film Thickness Estimation
Authors: Birnie Dunbar P.
Published: February 2023

It is well known that thin films within a certain thickness range will display interference colors. This is commonly seen for oil films on water surfaces, for thermal oxide on silicon, etc. This behavior is used to technological advantage when fabricating optical filters using multilayers of thin transparent films. It is also the basis for the thermal oxide thickness/color appearance charts that often appear in semiconductor processing textbooks.
Anisotropic Scatter From Tilted Columnar Cerium Oxide Films
Authors: Hodgkinson Ian , Cloughley Sarah , Wu Qi hong , Kassam Samer
Published: February 2023

The spatial distribution of optical scatter or haze from tilted columnar birefringent films is often highly anisotropic, even when the films are illuminated at normal incidence.1,2 During a recent investigation some titania films were found to give asymmetric forward and backward scatter patterns that were visible on a plane white screen to the naked eye. Subsequently the use of the white painted inside surface of a hemispherical shell centred on the sample was found to improve visualization of the spatial distribution of scatter.1
Performances of Mirrors with low losses and high laser damage thresholds
Authors: Schmitt Bernard , Dufour Françoise , Piombini Hervé , Henry Roger
Published: February 2023

For its laser applications, the C.E.A requires visible broadband optical components with very high characteristics in laser damage thresholds and low total losses. The level of performances reached having a direct impact on costs of developed laser systems, the compromise between the laser damage thresholds and total losses must be the best one.
Determination of Refractive Index Profiles by Combining Visible and IR Ellipsometry Measurements
Authors: Van Nguyen V. , Brunet-Bruneau A. , Fisson S. , Frigerio J.M. , Vuye G. , Wang Y. , Abelès F. , Rivory J. , Berger M. , Chaton P.
Published: February 2023

The determination of refractive index profiles in transparent layers, like every inverse problem remains a difficult task. The chance to get a realistic solution depends of course on the magnitude and shape of the profile and on the distance over which it is spread out. Two classes of problems can be identified: non intentional gradient resulting for example from the microstructure of the evaporated films (columnar growth in dielectric films) DI, or the adsorption of a polymer solution onto a solid wall[2], and intentional gradients designed for specific applications. In the second case, the profile deduced from optical measurements can be compared with the target after taking into account the errors introduced during the deposition process. The results that we present in this paper concern compositional gradients in silicon oxynitride films.
Ellipsometry of light scattering from thin film multilayers
Authors: Deumié C. , Giovannini H. , Albrand G. , Akhouayri H. , Amra Claude
Published: February 2023

Many studies are devoted to the study of light scattering1 in multilayer optics, and enable to improve our knowledge of microstructural parameters such as interface roughnesses and bulk inhomogeneities inside the stacks. However these studies are mainly based on the intensity of the scattered light, while phase measurements may provide additional and precious information when analysing the scattering data.
Characterization of Surface Particulate on Large Optics For Laser Fusion
Authors: Rigatti A. L. , Smith D. J. , Lund L.D. , Glenn P. , Glenn J.
Published: February 2023

A unique mapping instrument which locates and classifies the size of particulate contaminants has been built to quantify optical surfaces on substrates as large as 14 inches by 27 inches. The idea of a defect mapping system (DMAP1) was originally investigated as an evaluation tool in the fabrication of liquid crystal devices. Removal of surface particulate is critical to the manufacture of high laser damage resistant LC devices.1 During operation of Omega, a high-peak power laser system, random particles on an optical surface are vaporized and contamination is left behind. The major failure mode for LC devices is the decomposition of the LC fluid layer due to the heating of extrinisic impurities trapped within the cell. Use of this new surface characterization equipment will not only benefit LC production but it will be important in the evaluation of cleaning procedures prior to coating optics.
Optical Coatings For Document Security
Authors: Phillips Roger W.
Published: February 2023

Optical coatings that display color shifts with viewing angle are ideal candidates for document security devices since the average person can detect the color shift and such shifts readily defeat color copiers, printers and cameras. Documents made using these instruments do not have the telltale color shift of the original and thus can be readily identified as being counterfeit. The optical signature in its final product form must also be immune to simulation and origination. Furthermore, it must be able to withstand all the rigors arising from normal handling and machine verification.
Union of thin-film optics and diffractive optics: improving diffraction gratings with optical interference coatings
Authors: Li Lifeng
Published: February 2023

Both diffraction gratings and optical interference coatings are used in a wide range of applications. While the basic theory of thin-film optics is well covered in many optics text books and many books on the design, fabrication and application of optical coatings have been published, the treatment of diffraction gratings in optics text books goes little beyond presenting the grating and to date only three books on diffraction gratings have been published. The book edited by Petit1 describes the electromagnetic theory of gratings. The book by Hutley2 concentrates on the physics of gratings. Complementing the above two, the recently published book by Loewen and Popov3 aims at the applications of gratings. In addition, a volume in SPIE’s milestone series, edited by Maystre4, contains many important papers in all aspects of gratings up to 1992.
High-Efficiency Diffraction in Spiders
Authors: Hegedus Zoltan S.
Published: February 2023

Many animals in the insect/spider world exhibit strong metallic colours [1]. Such colouration is usually called structural, because the effects are caused by diffraction of light on semi-regular structures at the scale of the wavelength. The surface of the C. thalassina, when observed in an electron microscope shows well developed almost regular grooves, Fig. 1. On a large scale (sub mm) the grooves are wavy but they maintain a remarkably constant sub-micrometre period. The periodicity is near 0.46 pm and the depth is estimated to be 0.15 μm.
The Fabrication of Rugate Filters by Reactive Sputtering
Authors: Lewis K L , Blacker R S , Bennett R , Simpson J , Pitt A M
Published: February 2023

The reactive sputtering technique provides an attractive approach for the fabrication of rugate filters. Such complex filters usually require a great deal of care in process control, to the extent of integrating some measured characteristic of the product such as optical reflectivity into the control algorithms. The general acceptance of rugate filters as commercial products has been hampered by these complexities of process control and by the difficulties of transitioning lessons learned in small scale research facilities to large scale box-coaters. Significant advances have recently been made in the development of planar magnetron sources and their associated power supplies. The technology provides for benefits in source stability, high deposition rates, high uniformity and under the correct conditions, allows sufficient ion bombardment of the growing film to achieve full densification at temperatures close to ambient.
Characteristics of SiOxFy Thin Films Prepared by Ion Beam Assisted Deposition
Authors: Lee F.J. , Hwangbo C.K.
Published: February 2023

As low refractive index materials in visible wavelength SiO2, MgF2, and Na3AlF6 have been used in the optical thin film coatings. While MgF2 and Na3AlF6 films have lower refractive index than SiO2 films, their mechanical properties are not as good as SiO2 films. On the other hand, in the semiconductor industry fluorine-doped SiO2 (SiOxFy) films prepared by the CVD method have been developed as an inorganic low-dielectric constant material.[1] In this study, we fabricated SiOxFy films by ion beam assisted deposition (IBAD) to utilize them in the optical coatings as a low index material with a better mechanical property and investigated the optical, mechanical, chemical properties of SiOxFy films.
Operation of a Gridless Ion Source for Ion Assisted Deposition
Authors: Sainty Wayne G
Published: February 2023

In a commercial optical coating environment, the significant benefits of the gridless end-Hall ion source have been exploited, resulting in a new design.
Ion-Assisted-Deposition using a High-Output End-Hall Ion Source
Authors: Fulton Michael L. , Cabrera Robert
Published: February 2023

Over the last ten years considerable effort has gone into the development and use of Ion-Assisted-Deposition (IAD) in the manufacturing of optical thin-film coatings.1-4 During the last 6 years a collaborative effort has finally culminated in producing a “High-Output” Mark II ion source. Compared to the standard 5 Amp Mark II the new source raises the anode current limit from 5 to 15 Amps and the voltage from 170 to 275 Volts. This higher operating limit has opened a huge new parameter space in which to investigate the materials and processes involved in the production of thin-film optical filters.
Radical Activated Chemical Vapour Deposition of Oxides
Authors: Bennett R.H. , Simpson J. , Lewis K.L.
Published: February 2023

Traditional chemical vapour deposition processes, as widely used in the semiconductor industry, involve the introduction of a vapour phase organometallic precursor material to the reaction chamber, where decomposition of the vapour to form a solid film is triggered by heating the substrate. CVD methods for fabrication of optical thin film devices are becoming increasingly popular and there is a continuing drive towards plasma based CVD systems which promote deposition at lower substrate temperatures, allowing film growth on less temperature tolerant substrates.
Properties of AIN thin films deposited by various techniques
Authors: Atanassov George , Lee Cheng-Chung , Dimitrova Valentine , Dai Yisheng
Published: February 2023

AIN material is well known with its high band gap, electroinsulating and piezoelectric properties, chemical stability, hardness and high decompoition temperature [1]. AIN thin films find large application in microelectronics and optoelectronics. They are good thermal conductors and resistant to thermal shocks [2], So far they do not find large application in optical coatings due to the technological difficulties in their production and large compressive stress. The films are subjected to oxidizing during heating under ambient air, which leads to reducing their refractive index and change of their mechanical and other physical properties [3], Additional big problem so far is the higher extinction coefficient of AIN, which normally exceeds 10-3 and make it unacceptable for many optical applications. Nevertheless, AIN is a prospective material for deposition of multilayer stacks of type Al2O3/AlN or index profile coatings from evaporation or sputtering of metal Al and alternative changing the reactive gases in the vacuum chamber. Deposition of AIN thin films with high refraction index, low extinction coefficient and small mechanical stress still seems a challenging task.
Emission pattern of real vapor sources in high vacuum
Authors: Villa F.
Published: February 2023

It has been known for a long time that vapor sources in high vacuum behave following closely the Knudsen's laws[1] if the hypothesis of his theory are well fulfilled. The characteristics of many sources used on PVD methods like thermal evaporation, electron beam gun, sputtering, etc. commonly depart from a Knudsen's theory[2-3], however a proper modification of the hypothesis of this model can explain and model the experimental emission pattern of this vapor sources.
Fractal Surfaces and Multiscale Polishing
Authors: Deumié C. , Amra C.
Published: February 2023

Roughness is well known to be bandwidth dependent [1,2]. As a consequence, a surface may be superpolished for applications at visible wavelengths, but highly rough when illuminated with X-rays. Therefore it has become of relevant interest to predict the spectral variations of roughness. These variations must be taken into account in any normalization rule. Moreover, they permit to know at which wavelengths specular fluxes start to vanish before they are turned into diffuse fluxes.
Scattering of light from a film with a random rough surface on a metallic substrate
Authors: García-Llamas Raúl , Márquez-Beltran Cesar , O’Donnell Kevin
Published: February 2023

In a series of papers, the first in 1994, Sánchez-Gil et al [1] and in 1997 Madrazo and Maradudin [2] studied the scattering of electromagnetic waves from a wave guide film on a perfect conductor with a random rough surface. They found the enhanced backscattering and satellite peaks in the incoherent part of the mean differential reflection coefficient (DRC) as a function of the scattering angle when the system supports several guided waves modes.
Phase Detection of Roughness Correlation Within A Stack: Angle Resolved Ellipsometry of Light Scattering
Authors: Deumié C. , Giovannini H. , Amra C.
Published: February 2023

While most scattering studies are currently based on the intensity of the scattered waves, relevant additional information can be found in the complex amplitude of these waves, characterized by a phase term. In this context first results were presented at the previous Tucson Meeting that concerned a technique based on the angle-resolved ellipsometry of light scattering [1].
Colour-Separating Multilayer Systems Used for TFT-LCD Projectors
Authors: Gu P.F. , Zhang Y.G. , Zheng Z.R. , Li H.F. , Liu X. , Tang J.F.
Published: February 2023

The projection display system using TFT-LCD technology will be the wave of the future for large screen displays. It has the advantages of compact in design, large display area, high quality of output image and lower cost. In such a projector, it is the combination of both the electronic and the optical technology. It should be emphesized that the optical system is one of the most important parts for determining the quality of output image, such as brighness, comtrast ratio, colour fidelity and illumination uniformity.
Transfer of information relating to the optical properties of a multilayer
Authors: Baumeister Philip
Published: February 2023

There are many instances in which rays are traced through an optical coating. Suppose that a ray impinges upon an optical coating at nonnormal incidence. The coating may alter that ray in the following ways: (1). A radiant reflectance of less 100% attenuates the reflected ray. (2). The phase shift upon reflection alters the phase of the reflected ray. (3). Any loss due to absorption or transmission attenuates the ray. (4). The phase shift upon transmission alters the retardance of the ray. (5). Effects (1) to (4) alter the state of polarization of the ray.
Sputter-Deposited Electrochromic Films of Tungsten Oxide: A Study of the Effects of Varying the Target-Substrate Distance
Authors: Lee W. J. , Fang Y. K. , Huang Daoyang , Ho Fang C.
Published: February 2023

Electrochromic properties of transition metal oxides have been extensively studied in recent years due to their potential application as " smart " optical-switching window materials.1,2,3,4 In particular, tungsten oxide outperforms most of other transition metal oxide films and thus draws most attention from researchers.5 Tungsten oxide film can be prepared by many methods, including electron-beam evaporation, thermal vacuum evaporation,2 chemical vapor deposition, sol-gel deposition, and sputter deposition. Among these methods reactive sputtering is most suitable for large area applications such as automobile glass and architecture building glass.
Optical Interference Filters in Thermophotovoltaic Applications
Authors: Jarefors Kenneth , Broman Lars , Marks Jorgen
Published: February 2023

A thermophotovoltaic generator of electricity consists of an emitter of electromagnetic radiation and a photovoltaic cell. The emitter is heated to a temperature typically in the range 1500 K to 2000 K. Since the radiated photons in the spectrum from a terrestrial emitter have much longer wavelength than the sun's, PV cells optimized for solar applications are less well suited to TPV applications. A solar cell bandgap is typically 1.2 eV or above; the figure given is for XSi-cells (crystalline silicon cells). The TPV cell bandgap is a compromise between several factors including optical optimum and mechanical stability. Popular candidates are GaSb (Eg = 0.78 eV) and InxGa1-xAs (Eg between 0.6 and 0.8 eV) thin film cells.
Thin film luminescence under UV illumination
Authors: Begon C. , Rigneault H.
Published: February 2023

Visible luminescence of different substrates and thin films materials is studied under nanosecond pulsed UV radiation (335nm). Specific spectra are found to be an intrinsic characteristic of the various coatings materials. Radiative decays are also measured and found to be in the nanosecond time scale.
Worst-case performance of multilayer coating designs
Authors: Noe Tony D.
Published: February 2023

Before manufacturing a multilayer coating, it is important to know how the coating performance (e.g., reflectance, transmittance, etc.) will be affected by manufacturing errors. If the performance is very sensitive, it may mean that the coating is not manufacturable or that it will need to be manufactured using a more accurate process. A survey of various methods is given by Macleod [1] and Liddell [2].
Temperature-Invariant Infrared Filter
Authors: Fan Bin , Zhang Fengshan , Zhang Suying , Zhu Lingxin
Published: February 2023

Lead telluride (PbTe) and zinc selenide (ZnSe) are Important infrared coating materials. Their spectral characteristics are highly temperature dependence. The temperature coefficient of refractive index of PbTe is about -2.0 × 10-3/K, that of ZnSe is about 4.8 × 10-5/K. The central wavelength of the filters composed of PbTe and ZnSe usually shift toward longer wavelength with a decrease in temperature[1]. Seeley et, al[2] took advantage of negative temperature coefficient of PbTe to design filters which are relatively temperature-invariant. But for the most cases, it is difficult to manufacture temperature-invariant filters of PbTe and ZnSe.
Dielectric Thin Films to take up the microcavity challenges?
Authors: Rigneault H. , Robert S. , Amra C. , Begon C. , Gérard J. M.
Published: February 2023

Spontaneous emission control for luminescent species located inside multilayer dielectric thin films is investigated theoretically in the framework of classical and quantum electrodynamics. Theory is compared to experimental results concerning rare earth ions implanted inside Ta2O5/SiO2 microcavities. We show that although the planar cavities can control the radiation pattern of sources, these structures are unable to affect significantly the atomic lifetime. The first attempts to etch 3D microcavities are presented.
Coatings on Plastics
Authors: Cormia R. L.
Published: February 2023

Vacuum coated plastics, and more specifically, sputter coated flexible webs of polymeric are the subject of this review paper. While vacuum coating of flexible webs has been a commercial reality for over 50 years, it is only since 1979 that webs have been sputter coated using planar magnetron sputtering. After presenting a brief history of the December 1972 Chapin invention of the planar magnetron, and the development path for application of planar magnetrons to coating of large areas, this paper will chronicle the experiences of this author in the creation of a useful technology for the production of products based upon the deposition of metals and dielectrics in one continuous process onto a flexible polyester web.
Effect of interphase on the properties of optical filters fabricated by PECVD on polycarbonate
Authors: Bergeron Adam , Poitras Daniel , Martinu Ludvik
Published: February 2023

Plastic substrates take a major place in the optics industry today1. They are less fragile than glass and can be easily molded in any shape. However, considerable effort is needed to improve the quality of optical coatings on such substrate, particularly to increase their adhesion and scratch resistance. These difficulties are mainly due to the softness and low surface energy of the polymer surfaces. Plasma deposition is an attracting approach to deposit good quality optical filters at a high rate and a favorable cost. Various pretreatments can be applied in order to increase the adhesion of coatings on plastics, such as predeposition of a hard layer,2 or surface modification by plasma pretreatment.3 Due to a synergistic effect of ions, photons and free radicals with exposed polymer surfaces, PECVD on plastics has been found to create a physically thick “interphase”.3–5 In this work, we study this interfacial region between silicon-compound films and a polycarbonate (PC) substrate. Evidence of the presence of an interphase will be demonstrated by spectroscopic ellipsometry (SE) and spectrophotometric measurements, and its impact on the performance of optical filters will be shown.
Characterizing UV induced polymer degradation with spectroscopic ellipsometry
Authors: Bungay Corey L. , Tiwald Thomas E. , Woollam John A.
Published: February 2023

Polymers are susceptible to altered chemistry from UV radiation. The absorption of UV photons can promote breakage of important functional groups and structural bonds, such as C=C and C=O [1]. When an organic molecule absorbs UV radiation, it will be excited into higher energy states and possibly dissociate bonds. Dissociated radical species can then participate in additional reactions. Changes in chemistry may affect optical properties, which can have serious effects for polymers used in optical systems.
Evaluation of the solutions for the 1998 design problems
Authors: Baumeister Philip
Published: February 2023

Two problems were proposed: Dual band antireflection and a bandpass filter.
Absorbing and scattering centers in subthreshold irradiation processes
Authors: Gatto A. , Roche P. , Commandré M. , Dijon J. , Berger M. , Garrec P. , Pellé C. , Ravel G.
Published: February 2023

Absorbing defects are suspected to play a part in laser damage of thin films especially in the UV spectrum1,2. To improve the coating technology, it seems to be very useful to get more information on the localized defects and their relation to damage threshold: the size and the nature of these defects are important questions. Simultaneous mapping of absorption and scattering together and their correlation give specific information about the nature of defects3. Furthermore during their life, UV optical components have to withstand millions of high intensity pulses and can be damaged by long term subthreshold irradiation. Localized losses can play an important part in these phenomena. The present work tries to elucidate the role of absorbing and/or scattering defects in titania and silica films deposited by DIBS on fused silica substrates and irradiated with increasing numbers of shot at subthreshold fluences.
Evaluation of spectral properties of multilayers consisting of slightly inhomogeneous layers
Authors: Tikhonravov Alexander V. , Trubetskov Michael K. , Voronov Andrei V. , Smith Douglas J.
Published: February 2023

1. Inhomogeneous films have been the subject of detailed study for many years.1,2 Multilayers consisting of slightly inhomogeneous layers may be considered as a particular case of inhomogeneous films. This class is of special practical interest because layers of many optical coatings are slightly inhomogeneous.
Needle optimization for general merit functions
Authors: Noe Tony D.
Published: February 2023

Needle optimization [1, 2, 3, 4] is a powerful technique for finding good starting designs, which traditional local optimization methods can then refine into useful coating designs. Because modem coating designs may require the use of unusual merit functions, it is important to know when the needle method can be employed successfully. This paper shows a new formulation of the needle optimization method and explores several general merit functions.
Anisotropic Protective Coating for Brewster-Angle Windows
Authors: Surdutovich G.I. , Vitlina R.Z. , Baranauskas V.
Published: February 2023

Usually any anti-corrosion protective coating worsens to some extent the optical properties of the object. This is also related as well to Brewster-angle windows since the null reflectivity at the Brewster angle is a property of a flat interface between two lossless dielectrics, which can never be obtained with an isotropic film-covered substrate. It is possible, however, to design some specialized anisotropic coatings deposited onto the Brewster angle window which sustain exactly the position of the Brewster angle and a true zero of the reflection factor.
Bistable Optoelectronic Devices in GaAs
Authors: Lau K.Y. , Yariv A.
Published: February 2023

Bistable switching devices occupy a central role in the area of signal processing. Electronic switching devices (electrical in - electrical out) commonly known as Schmidt trigger are key elements in the general area of analog and digital signal processing by electronic means. It seems inevitable that optical computing and signal processing systems will eventually incorporate some form of optical bistable switching elements. Purely optical bistable devices (optical in - optical out) have, through investigations in recent years, made very substantial advances in terms of switching speed and optical power requirements. In order to extend the range of problems that optical computing systems are capable of handling, it has been suggested that future optical computing systems may not be purely optical in nature but rather an amalgam of optical and electronic processing elements in order to take advantage of the best of both worlds. In this respect, bistable optoelectronic devices that are capable of switching by optical and/or electrical signals, and have their outputs available in both optical and electrical forms, may play a unique and useful role in these hybrid systems. Recent advances in these kinds of bistable devices based on interaction of optical (lasers, detectors) and electronic (transistors) devices monolithic integrated on GaAs substrates will be described in this paper. Switching speeds in the sub-nanosecond regime (as short as 50ps) and optical switching powers in the 10mW/cm2 range have already been demonstrated in these devices. The purpose of this presentation is to familiarize researchers in the field of optical computing with new possibilities and venules of investigations brought about by these recent advances.
Optical Window Addressable Memory Processing
Authors: Condon D. J. , Reichenbach M. C. , Tarasevich A. , Rhodes W. T.
Published: February 2023

An electro-optic approach to the selection of the closest match between an object described by a feature vector and a set of known feature vectors is described. The problem is formulated as parallel vector-matrix multipliers and a summing operation of the form: Typical problems usually do not call for an exceptionally rapid update of the stored information, while the rapid sorting operation is generally a strong requirement. These conditions can be satisfied with currently available technology. An implementation is described in which feature vector data is stored on a liquid crystal device utilized as a window addressable memory. A description of breadboard hardware is given. Preliminary test results support the overall feasibility of the approach.
Optical Boltzmann Machines
Authors: Ticknor Anthony J. , Barrett Harrison H. , Easton Roger L.
Published: February 2023

Optical systems for calculating the cost function and a random number distribution in a Monte Carlo reconstruction are described.
Concept of Array Processing with Optical Integrated Circuits Controlled by External Optical Signals
Authors: Ishihara S. , Yajima H.
Published: February 2023

The application of optical integrated circuits to optical computing has been discussed in the literature; for logic operations[1~3], for residue arithmetics[4~6], for polynomial processors[7], and so on. The optical integrated circuits are suitable particularly for optical array processing because the elementary devices can be easily duplicated and arranged in regular way with so-called step-and-repeat process. Until recently, those integrated circuits are usually controlled by external electric signals (Fig.1 a); which cause the input bottleneck problem as well as electro-magnetic interferences from both the environment and control signal wires themselves. In this paper, the concept and advantages of optical array processing with optical integrated circuits whose functions can be controlled by external ‘optical’ signals[8](Fig.1 b) are discussed.
Versatile Two-Dimensional Optical Circuit Arrays
Authors: Warde C. , Kottas J.
Published: February 2023

We are investigating several classes of versatile, alloptical, open and closed loop circuits that are based on two novel devices: a microchannel spatial light modulator (MSLM) and a laser beamlet array generator (BAG). The MSLM is illustrated in Eig. 1 and is described in detail elsewhere. 1-3 Essentially, it consists of a sandwich of photocathode material, a microchanneJ. plate (MCP), an acceleration grid and a thin electro-optic crystal. The electro-optic crystal is coated on the side lacing the MCP with a dielectric mirror and on the other with a transparent electrode. This entire assembly is enclosed i n of a r e Hz ) and the an evacuated tube. The important and the MSLM that make it well suited for its low halfwave exposure ( 5 0 storage characteristics, the abib111y to wr same wa ve1e n g t h. importance because it opt leal circuits.
Outer Product Expansions: Approximate Singular Value Decompositions Of Ill Conditioned Matrices
Authors: Gruninger John , Caulfield H.J.
Published: February 2023

It is possible to express a matrix as a weighed sum of outer products of column and row vectors. The set of column vectors forms a basis for the columns and the set of row vectors forms a basis for the rows. The number of column (row) vectors required to span the columns (rows) of the matrix is defined as the rank of the matrix. If the elements of the matrix have uncertainties due to measurement errors and/or computer representations, the determination of rank can be difficult. We define pseudorank as that number of columns (rows) vectors required to reproduce the matrix to within the uncertainties of measurement and reproduction. Matrices that occur in image analysis and pattern recognition are often of very high dimension but have low psuedorank. For such matrices, an outer product expansion provides a significant data compression. Below a technique for finding truncated outer product representation of such matrices is described. The determination of approximate singular value decompositions and pseudoinverses follows directly.
Space Integrating Acousto-Optic Matrix-Matrix Multipliers
Authors: Wagner K. H. , Weverka R. T.
Published: February 2023

Space integrating pipelined matrix-matrix multipliers using multichannel Bragg cells and parallel output detector arrays are proposed as an appropriate optical implementation of systolic arrays.
Optical Computing — An Overview
Authors: Goodman J.W.
Published: February 2023

The field of optical computing finds itself at a convergence of two different technological streams. One stream flows from the field of analog optical information processing, while the other flows from the field of nonlinear optical devices. Both streams are attempting to reach the same destination, namely a useful computer based on optical technology.
Parallel Interfacing of Integrated Optics with Free-Space Optics
Authors: Lohmann Adolf W.
Published: February 2023

There exist two distinct optical technologies with potential for data processing: integrated optics (IO) and free-space optics (FSO). The IO techno logy is well suited for performing optical nonlinear interactions and electro-optical control operations. As a planar technology, IO can implement one-dimensional parallelism quite naturally, but not so well two-dimensional parallelism. The FSO technology on the other hand, is very well suited for two-dimensional parallelism. But in terms of nonlinear interactions FSO is lagging behind IO.