bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of Ring Tool Misalignment Using an Imaging Method
Authors: Xie Tong , Greivenkamp John E.
Published: February 2023

The Opticam computer-controlled optical surface generator1 uses a cylindrical grinding geometry. The radius of curvature of the generated surface is determined by the radius of the ring shape diamond-impregnated cutting head and its tilt angle. The edge of the ring cutter will coincide with the part vertex when the machine is aligned. When the cutter axis is not properly aligned with the part axis, the generated surface will deviate from its desired shape.
Fabrication of Aspherical Ultraprecise Surfaces using a Tube (FAUST)
Authors: Fähnle O.W. , van Brug H. , van der Laan C.J. , Frankena H.J.
Published: February 2023

A novel fabrication technique for the generation of rotationally symmetric aspherical surfaces has been developed in a cooperation between the two upmentioned institutes at Delft. A machine tool based on this method is currently being prototyped. In this paper we will describe the characteristics of this method. FAUST (Fabrication of Aspherical Ultraprecise Surfaces using a Tube; Patent pending) is a line contact method for the generation of rotationally symmetric optical surfaces. It employs a selfcorrecting process and enables the use of loose abrasive ductile grinding [Gol91] and subsequent bowl-feed polishing [Win92] for the generation of both convex and concave aspherical surfaces of revolution.
Does Polishing Involve Fracture?
Authors: Lambropoulos J. C.
Published: February 2023

Izumitani [1982, 1986] has discussed four theories of glass polishing. These theories are briefly summarized below since they point out that an important glass mechanical property, the fracture toughness, has not been included to date in the interpretation of polishing.
Absolute Ritchey-Common Test for Circular Flats
Authors: Parks Robert E. , Shao Lianzhen , Evans Chris
Published: February 2023

The Ritchey-Common test is often used to test diagonal plane mirrors used as beam steering devices in front of large telescopes and several papers have been written about how to analyze the circular wavefronts resulting from these tests that have a near circular pupil.1,2 In this paper we address the problem of analyzing the oval shaped wavefront that results when a circular flat is tested in a Ritchey-Common configuration so that we can find the absolute figure of the flat. The procedure will be described in terms of Zernike polynomials but the method can be used for pure phase map data such as that obtained from phase measuring interferometers.
The Rapidly Renewable Lap: Models and Performance
Authors: Evans Chris J. , Parks Robert E. , Roderick David J. , McGlauflin Michael L.
Published: February 2023

The Rapidly Renewable Lap (RRL) uses a textured substrate over which thin films are slumped (Figure 1). The substrate provides the geometry of the lap and a localized texture, depending on the film thickness, properties, and how it is deformed over and adhered to the substrate. Abrasives, added to the film, lap or polish without touching or changing the substrate geometry. Depending on process parameters, the RRL gives brittle or ductile lapping and polishing.
Frequency Converter Design and Manufacturing Considerations for the National Ignition Facility*
Authors: Hibbard Robin L. , English R. Edward , De Yoreo Jim J. , Montesanti Richard C.
Published: February 2023

The National Ignition Facility (NIF), being constructed at Lawrence Livermore National Laboratory (LLNL), comprises 192 laser beams, Figure 1. The lasing medium is neodymium in phosphate glass with a fundamental frequency (1ω) of 1.053 µm. Sum frequency generation in a pair of conversion crystals (KDP/KD*P) produces 1.8 MJ of the third harmonic light (3ω or λ =0.35 µm).

On NIF the frequency conversion crystals are part of the Final Optics Assembly (FOA), whose two principal functions are to convert the laser light to 3ω and focus it on target. In addition, the FOA provides a vacuum window to the target chamber, smoothes the on-target irradiance profile, moves the unconverted light away from the target, and provides signals for alignment and diagnostics. The FOA has four Integrated Optics Modules (IOM), Figure 4, each of which contains two 41 cm square crystals are mounted with the full edge support to micro radian angular and micron flatness tolerances.

This paper is intended to be an overview of the important factors that affect frequency conversion on NIF. Chief among these are angular errors arising from crystal growth, finishing, and mounting. The general nature of these errors and how they affect frequency conversion, and finally the importance of a frequency conversion metrology tool in assessing converter performance before opto-mechanical assemblies are installed on NIF will be discussed.
Comparison of diamond-machining and replication methods for producing high-quality metal mirrors
Authors: Ahmad Anees
Published: February 2023

A number of optical systems for commercial, military and space applications are subjected to very high dynamic loads and large temperature changes during operation and storage. In such applications, metal mirrors offer a number of cost and performance advantages as compared to mirrors made out of ceramic or glass materials. By making the mirrors and support structure from the same or similar metals, the differential thermal expansion and thermal gradients can be greatly reduced. In case of mirrors of complex shapes, such as off-axis aspherical or cylindrical, making them from suitable metals offers significant cost advantages because other low-cost high volume fabrication methods can be employed. Metal mirrors of an-open back design can also be light-weighted resulting in a significant overall system weight reduction.
Versatility of the differential rotationally-shearing interferometer for testing the aspherical surfaces
Authors: Páez Gonzalo , Scholl Marija Strojnik
Published: February 2023

The rotationally-shearing interferometer has been proposed as the instrument that may be used to record optical or infrared signal from an extra-solar planet.1 Also, its capacity to detect only the rotationally asymmetric aberrations has made it ideal for the asphericity testing of a glass sphere. The intensity patterns of the rotationally-shearing interferometer have been investigated previously for the specific angles of 902 and 180 degrees3,4. We present the simulated interferometric patterns for the tilt, astigmatism, coma, and their sum, as obtained in a rotationally-shearing interferometer for small and large shearing angles. The intensity patterns are calculated using the for a two-beam interference.
The Fabrication and Testing of Optics for EUV Projection Lithography1,2
Authors: Taylor John S. , Sommargren Gary E. , Sweeney Donald W. , Hudyma Russell M. , Gullikson Eric M.
Published: February 2023

Extreme UltraViolet Lithography (EUVL) is a leading candidate as a stepper technology for fabricating the “0.1 µm generation” of microelectronic circuits. EUVL is an optical printing technique qualitatively similar to Deep UV Lithography (DUVL), except that 11-13nm wavelength light is used instead of 193-248nm. The feasibility of creating 0.1µm features has been well-established using small-field EUVL printing tools, and development efforts are currently underway to demonstrate that cost-effective production equipment can be engineered to perform full-width ring-field imaging consistent with high wafer throughput rates. Ensuring that an industrial supplier base will be available for key components and subsystems is crucial to the success of EUVL. In particular, the projection optics are the heart of the EUVL imaging system, yet they have figure and finish specifications that are beyond the state-of-the-art in optics manufacturing. Thus it is important to demonstrate that industry will be able to fabricate and certify these optics commensurate with EUVL requirements.
Cylindrical Micro-Fabrication for Optical Fiber Ferrules by ELID-Centerless Grinding
Authors: Ohmori Hitoshi , Li Wei , Moriyasu Sei
Published: February 2023

The development of the micro-fabrication of structural components such as ceramics, optical glass, alloy steels etc., is increasingly required with the rapid growth of production in the recent years. The ELID (Electrolytic In-Process Dressing) grinding technique is a new grinding process using rigid metallic bond diamond wheels with the assistance of a special pulse electrolytic in-process dressing method.
Roof-Angle Error Measurement Using an Imaging Method
Authors: Suzuki Takamasa , Greivenkamp John E.
Published: February 2023

Measurement of the roof-angle error of prisms is a traditional task in optical measurement. Some established measuring devices, such as interferometers1) and autocollimators, are commonly used. Interferometers are expensive equipments. The autocollimator is simple to use, but it takes time to measure and is not suitable for automatic analysis.
Preliminary performance data from a high spatial frequency resolution 24-inch interferometer
Authors: Wilkins P. R. , McBurney M. S. , Novak E.
Published: February 2023

The National Ignition Facility is a next generation inertial confinement laser which will need approximately 7,000 large, square aperture optics with a clear aperture of approximately 430 mm on a side. The optics utilized in the laser required a unique set of wavefront specifications because of the extremely high fluences and nonlinear processes that affect the wavefront intensity evolution at these extreme power densities. The optical wavefront specification for these large optics is subdivided into specific spatial frequency regions, the lowest part defined in terms of a RMS wavefront gradient and the higher spatial frequencies limited to not exceed a maximum Power Spectral Density (PSD) defined in greater detail elsewhere.1 In order to verify that these spatial frequency wavefront specifications have been met, the NIF Program has contracted to Veeco Process Metrology (formerly Wyko) a 24-inch phase modulating interferometer capable of extremely high spatial frequency resolution to measure PSD over an operational range of 0.03 to 1.25 mm-1.2 This instrument is a standard Fizeau configuration interferometer with a linearly polarized 650-nm DFB diode laser source and a 1024 x 1024 pixel CCD detector. The optical imaging system has two fixed zoom settings, the lowest corresponding to a spatial viewing area of 431 x 431 mm square centered within the 24-inch diameter fused silica transmission sphere. The high spatial frequency zoom setting provides a 100 mm x 100 mm square aperture with a diffraction limited imaging lens designed to have an MTF > 0.9 at 0.4 mm-1 and MTF > 0.6 at 1.25 mm-1.
Fibre-based Shearing Interferometer
Authors: van Brug Hedser
Published: February 2023

In interferometry, two major problems exist. First, optical components can change the phase distribution, and second, the fringe density that can be too high to be resolved by the picture elements on a CCD camera.
Surface Smoothing Effects of Thin Film Deposition
Authors: McNeil J. R. , Wei L. J. , Al-Jumaily G. A. , Shakir S. , McIver J. K.
Published: February 2023

Surface microroughness and associated light scatter characteristics are important issues in the development of high quality optical components. Similarly, the effects of thin films deposited on an optical component need to be considered. When the film material is metallic, light scatter is due to surface microroughness; dielectric coatings can have light scatter contributions from surface as well as bulk effects (e.g., film microstructure).
Ion-Beam-Assisted Deposition of Optical Films
Authors: Netterfield R.P.
Published: February 2023

Substantial modification to the optical properties of vacuum deposited thin films can be made by bombardment of the growing film with ions. The packing density of evaporated dielectric films can be increased from approximately 0.75 to unity thereby producing films which have reproducible, stable properties. The ion-bombardment can also produce changes in the crystal structure and orientation of the films. Enhanced reaction rates and incorporation of the impacting gas in the film are also associated with the process.
Nonpolarizing edge filters, II
Authors: Thelen Alfred
Published: February 2023

Nonpolarizing edge filters at oblique incidence became recently important for demultiplexers for fiber communications1. By abandoning the concept of detuned Fabry-Perot interference filters for the design and applying classical Herpin equivalent layer theory, the number of usable structures can be greatly expanded and closed equations for aligning the edges in all cases can be derived.
Notch (narrowband-rejection) Filter at 10.6 μm Wavelength
Authors: Seeley J.S. , Hunneman R. , Whatley A.
Published: February 2023

Design theory, manufacture, and performance are discussed for a "notch" filter. Notches are necessarily those minus–filters (Thelen 1971), structurally tapered to compensate gross dispersion adjacent to the notch wavelength. Alternatively, compensation can be provided without tapering by a single HERPIN-period at each interface: we find this to be both practicable and adequate, but quite sensitive to refractive index. For the notch, per se, we prefer the particular non-quarterwave stack (described by Thelen) which has one layer index identical to the substrate. The accompanying index is not restricted and, whatever its value, bandwidth is easily varied by adjusting thickness ratio in the stack. Substrate antireflection is provided at the outer surface, and we find that the two-layer half/quarter (or W-type) coating is best to compensate notch dispersion (we assume because the constituent half/quarter indexes straddle the substrate index).
Optical coatings with radially variable reflectance
Authors: Piegari A. , Emiliani G.
Published: February 2023

Radially variable mirrors can be of interest in various applications but they offer greet advantages expecially when employed in laser resonators.
Optical Characteristics of Oxide Materials Deposited at Low Temperature and High Temperature Using Ion Assisted Deposition
Authors: Williams Forrest L. , Boyer L. L. , McNeil J. R. , McNally J. J.
Published: February 2023

Although heating substrates during deposition to temperatures of 250°C or higher often improves film properties, this precludes the use of conventional techniques to deposit thin films onto substrate materials that degrade in high temperature environments. Ion assisted deposition (IAD) is a technique that can improve the performance of thin films produced by physical vapor deposition, even when depositing onto heated substrates.1-3 IAD can increase film packing density and improve film stoichiometry compared to conventionally deposited coatings, resulting in optical thin films having higher values of refractive index, less optical absorption and scatter, better adhesion, improved environmental stability and greater abrasion resistance.
Experimental Study of Substrate Temperature
Authors: Yen Yi-hsun , Shao Jian-xin , Xu Pei-zhong
Published: February 2023

Substrate temperature is one of the most important processing parameters for optical coating deposition, especially in infrared range in which most of high refractive index coating materials are narrow gap semiconductors. The properties of the coatings deposited with these materials are strongly dependent on the substrate temperature.[1]
Evaporative Property of ZrO2-TiO2 Material
Authors: Shuming Pang
Published: February 2023

The evaporative property of ZrO2-TiO2 mixture has been studied. The refractive index of ZrO2-TiO2 film has a linear relationship with the ratio of mixture. The gradient index film can he obtained on certain ratio of mixture. Distribution of Zr atoms on the inner surface of the melting pit is given. It proves that zirconium appears the fractional effect during the evaporation of ZrO2-TiO2 mixture.
High-Resolution Transmission Electron Microscopy of Thin Films
Authors: Eyring LeRoy
Published: February 2023

The high-resolution electron microscope has been used successfully to study the structure and morphology of thin films including interfaces at near-atomic resolution. Recently the technique has been expanded to study the dynamics of thin film transformations and reactions in real time. These techniques possess enormous potential for those who wish to obtain atomic-level information of value in characterizing thin-film deposits and the changes they undergo with a variety of treatments. Four illustrations are given here.
Analysis of Diffraction Anomalies in Multilayer-Overcoated Gratings
Authors: DeSandre L. F. , Elson J. Merle , Schwartz C.
Published: February 2023

In recent years, there has been considerable interest in the problem of diffraction from multilayer-overcoated diffraction gratings. A dielectric multilayer is commonly used on high-power optical elements. Beam sampling may be necessary to monitor the phase and shape of the wave front; however, ordinary beamsplitters frequently cannot survive this intense power level. To overcome this difficulty, a multilayer-overcoated, low-efficiency grating (where the grating amplitude is a few percent of the wavelength) is utilized that diffracts a small fraction of the incident energy for beam diagnostics while achieving enhanced specular reflection of the high-energy beam. Anomalous diffraction effects may result at specific angles of incidence resulting from the incident beam coupling into guided waves supported by the multilayer coating.
Acoustic Microscopy on Infrared Coatings
Authors: Gunkel Claus W.
Published: February 2023

The aim of this paper is to present very first results of acoustic microscopy on optical films, e.g. for infrared applications in the spectral region between 8 - 12 micrometers. It will be pointed out, that the acoustic microscopy is a useful tool to get informations from beneath the front surface of those optical coatings.
New Approach to Design and Production of Inhomogeneous Optical Coatings*
Authors: Bertram R.W. , Ouellette M.F. , Tse P.Y.
Published: February 2023

Increasingly demanding requirements are being placed on optical interference coatings and in many cases, accurate and reproducible depositions of large numbers of multiple layers are required to fit within the stringent demands of industry. In order to meet some of the more severe requirements, Cametoid Limited has carried out a program to develop inhomogeneous optical films. The objectives of the program were to derive the technical knowledge and capability to produce advanced optical coatings using the method of inhomogeneous films, both by design and refinement and by computer controlled production. This paper presents the technique used and results obtained.
Ellipsometric Measurement of Transverse Kerr Magneto-Optic Effects
Authors: Biricik V. W. , Nakatsukasa F. R.
Published: February 2023

Ellipsometry is a powerful technique for the experimental determination of optical constants of thin film materials. In this paper, a novel technique for accurate measurement of magneto-optic effects of the transverse Kerr effect is described. For thin film applications, magneto-optic effects manifest themselves as first order perturbations, making it difficult to accurately determine the magneto-optic constants of a given material.
Stabilization of the Optical Properties of Thin Film Systems
Authors: Furman Sh.
Published: February 2023

The level of stability of interference coatings, such as narrow-bandpass or edge filters, determines the effectiveness and the life time of many precision optical instruments. A considerable number of papers are devoted to the study of the mechanism of the change with time of the optical properties of interference coatings (the aging effect) and of the conditions ensuring their stabilization.
Detailed knowledge of optical coating design techniques may be superfluous to produce usable coatings
Authors: Baumeister Philip
Published: February 2023

The goal is to incorporate layers with producible thicknesses and refractive indices into an optical coating such that prescribed characteristics are met. These characteristics include the spectral radiant reflectance R, radiant transmittance T, and differential phase shift upon reflection Δ. In the global search mode,1 the computer selects the layer thicknesses and refractive indices needed to produce the desideratum. The foregoing process is often exceedingly consumptive of computer time. For that reason, a more widely used approach is that a starting design is fed to a computer code that improves it through optimization.
An Economical Exhaustive Search Procedure for Filter Design by Merit Function Minimization
Authors: Greiner H.
Published: February 2023

To find a minimum of the merit function describing the performance of an optical interference filter by exhaustive search, the following problem has to be solved: a set of m layer types which can be combined to form the filter is given. To identify a combination realizing an absolute minimum of the merit function by exhaustive search, the value of the merit function of all possible layer combinations comprising L layers has to be calculated and the one with the lowest value to be retained (for more details cf. ref. 1,2,3). Here we want to describe an implementation of the scheme which allows for considerable savings in computing time.
Fabrication and Operational Characteristics of A Gridless Ion Source and Preparation of SiO2 Thin Films
Authors: Hwangbo C.K. , Song S.K. , Park D.Y.
Published: February 2023

It is well known that ion-assisted deposition(IAD) has changed the optical, mechanical, and chemical properties of optical thin films. In a large chamber where ion beam should cover a large substrate area, a gridless ion source may be suitable because of its high ion current density, large divergence of ion beam, and low energy ion beam which leads to the low sputtering-out rate of growing films. Also, it is simple in fabrication, operation, and maintenance compared to a gridded ion source.
A Method for Reducing the Optical Absorption of Reactive Ion-Plated Metal-Oxide Thin Films
Authors: Zarrabian S. , Grogan A. , Hu X.-Q. , Lee C. , Guenther K. H.
Published: February 2023

For most films produced by condensation from the vapor phase (physical vapor deposition, PVD) their physical and chemical structure and hence their optical properties deviate from those of the bulk material of nominally the same composition.1 The extent of this deviation depends upon the particular deposition process.2 Reactive Low Voltage Ion Plating (RLVIP) produces high density thin films that exhibit long term stability.3 However, because of the deposition conditions, optical absorption can be a significant problem.4 For many demanding optical applications, such as in laser systems, it is necessary to minimize the absorption of the deposited thin films. In this paper, RLVIP and conditions leading to thin films with some undesirable residual optical absorption are summarized. We will also describe experiments where the addition of small amounts of nitrogen gas to the plasma process environment reduced the optical absorption of tantala films made by RLVIP.
Low Voltage Ion Plating Technique for the Deposition of ZnS, MgF2 Films
Authors: Liu X. , Zhen Y.F. , Zhang Y. , Gu P.F. , Tang J.F.
Published: February 2023

Low voltage ion plating technique has become more and more interest in the deposition of thin films with very high packing density and good adhersion properties. Current works in the world are concerned mainly on the films of oxides [1], [2], the films were prepared by evaporating correspondent metals or suboxides materials in a plasma cloud, and with a reaction of oxygen ions to form a correct stoichiometric oxide films.
Anisotropy in thin films: modelization and measurement of guided and non guided optical properties. Application to TiO2 films
Authors: Flory F. , Endelema D. , Pelletier E. , Hodgkinson I.
Published: February 2023

The main purpose of the work presented here is to study the anisotropic behavior of dielectric material in thin film form.
Using the Protected Gold Surface as a Reference Mirror for the Relative Reflectance Measurement
Authors: Wang Ran-Hong Raymond
Published: February 2023

A protected gold mirror was used as a reference mirror for the measurement of the reflectance between 600nm and 1700nm of samples in a double beam spectrophotometer. The results showed that the measurements were more accurate compared to those using an aluminum mirror or gold mirror as the reference. The FTIR reflectance curve indicated that the protected gold mirror shows almost zero absorption at the wavelength between 2.5um and 16um. This allows the protected Au mirror to be used as an ideal reference mirror with a range from 0.6um to 16um. Furthermore, abrasion testing (50 rubs by cheesecloth) caused no damage of the coatings on the protected Au mirror, which allows for regular cleaning.
Measurement of Birefringent Coatings by Envelope and Waveguide Methods*
Authors: Horowitz Flavio , Mendes Sergio Brito
Published: February 2023

Spectrophotometric and prism-coupler experimental data on thermally- deposited dielectric films are analyzed by Envelope and Waveguide Methods. A detailed comparison for Lead Fluoride and obliquely deposited Cerium Oxide coatings is shown.
Rugate Filter Deposition by the OMVPE Technique
Authors: Sankur H. , Southwell W. , Hall R. , Gunning W.J.
Published: February 2023

Organometallic vapor phase epitaxy (OMVPE) is a deposition technique that is increasingly applied to large scale manufacturing of electronic devices. This technique can produce single crystalline, high purity epitaxial layers with good thickness and composition controllability and can achieve high deposition rates (>10 nm/sec). For optical coatings, the crystalline nature of the layers ensures the absence of defects and therefore enhanced reliability and environmental stability.
Pulsed Plasma Deposition of Optical Filter Structures.
Authors: Sheach K. , Heinecke R.
Published: February 2023

In conventional plasma deposition systems, partial dissociation of the active gases is achieved by exposure to a continuous low power plasma (<5 Wcm-2). The free radicals so produced diffuse to solid surfaces and react thermally to produce a deposit. This is an efficient process in the production of passivating layers and rudimentary structures. In the fabrication of high quality and sophisticated optical elements such as reflection stacks, rugate filters and etalons, this process had been proven to be highly dependent on such factors as temperature, thermal gradients and gas distribution. Thus complex feedback monitors are normally required, in order to allow fluctuations in deposition rate to be corrected in order that filters be successfully deposited.
Amorphous Silicon and Silicon Nitride Films by Plasma-Enhanced CVD as Coating Materials
Authors: Tsai Rung-Ywan , Kuo Lee-Ching , Ho F. C.
Published: February 2023

It is well known that plasma-deposited silicon and silicon nitride thin films provide great characteristics for optical coatings in various applications (1-5). Since films prepared by plasma-enhanced CVD are homogeneous, durable, and also reproducible, it is very appropriate to design a multilayer stack which consists of alternating a-Si and a-SiNx layers. We present our study on this topic in the following sections.
Amorphous diamond?
Authors: Craigie C.J.D.
Published: February 2023

Diamond is a material of exceptional properties. It is hard, transmissive from the near UV into the IR, has a high thermal conductivity, a wide electronic band gap, and is generally considered to be chemically inert. From a thin film coating standpoint its low thermal expansion coefficient provides adhesion difficulties. If adhesion problems were solved, rigidity would make stress induced cleavage a problem.
The influence of Substrate Temperature on the Infrared Optical Constants of Silicon Monoxide Evaporated Thin Films.
Authors: López Fernando , de Frutos José
Published: February 2023

Optical properties of vacuum evaporated thin-films are highly influenced by the obtaining conditions of the layers [1] inside the vacuum chamber.
Optical and Durability Properties of Bi2O3, Cr2O3, HfO2, Ta2O5, Y2O3, and ZrO2
Authors: Traylor Jennifer D. , Pawlewicz Walter T.
Published: February 2023

The data in this paper were compiled from information collected from over 10 individual coating runs to provide the optical designer optical constants for six oxide thin film materials over the 0.6 – 12.0 µm wavelength region. Data are included for bismuth oxide (Bi2O3), chromium oxide (Cr2O3), hafnium oxide (HfO2), tantalum pentoxide (Ta2O5), yttrium oxide (Y2O3), and zirconium oxide (ZrO2). In addition, the durability of each film has also been examined.
Optical Properties of CeOxFy Thin Films Produced by Reactive Sputtering
Authors: Shu-ying Zheng , Stjerna Bertil , Granqvist C.G.
Published: February 2023

The purpose of our work is to observe the optical energy gap shift for amorphous thin films of cerium oxide produced by addition of CF4 to Ar and O2 gas mixture during rf sputtering of Ce target. It has been expected that the refractive index of cerium oxyfluoride in thin film form decreases as the CF4 concentration increases. Such bandgap- and index- controllable coating materials may be useful for both energy efficiency and optical multilayer devices.
The Effect of Composition on the Properties of Magnetron Sputtered Vanadium Oxide Films
Authors: Lewis K L , Pitt A M
Published: February 2023

The vanadium oxide system is well known for its multiphase behaviour. Many compositions are known, ranging from VO0.2 to V2O5. Several of these materials exhibit semiconductor-metallic phase transitions at temperatures between 10 and 400K, the most well known being found in the case of vanadium dioxide at 341K. A large number of studies have addressed the properties of thin films of VO2 using material deposited by a number of different techniques, but there is no systematic study reported of the sensitivity of the phase transition to composition in the range close to x=2.0. This work seeks to address this issue using material deposited by reactive sputtering using an RF planar magnetron source under ultra-clean (UHV-type) conditions. The problems posed in the use of reactive sputtering for the deposition of such oxide films arise because of the affinity of the metal target for the reactive gas used during sputtering which results in a highly non-linear process characteristic as discussed by Berg [1] and others. For the deposition of materials in their highest oxidation states (eg alumina, V2O5) etc), this doesn't usually present too much difficulty, since it is only necessary to provide sufficient reactive gas to overcome the level of poisoning at the target surface. In the case of vanadium oxide however, the control of composition is of paramount importance in achieving the optimum film properties.
Optimizing Birefringence In Columnar Coatings - A Problem For The Nanoengineer?
Authors: Hodgkinson Ian
Published: February 2023

When thin film materials such as titania and zirconia are deposited at an oblique angle on to a substrate a tilted columnar (TC) microstructure develops. Electron microscope observations of thin film sections show that the angle between the columns and the substrate normal is determined by, and somewhat less than, the deposition angle. In fact the tangent rule,1 which relates the two angles, was discovered after some of the earliest electron microscope observations on fractured thin film sections.
Efficient Refinement of Inhomogeneous Optical Coatings
Authors: Tikhonravov Alexander V. , Trubetskov Michael K. , Zuev Ilya V. , Verly P.G.
Published: February 2023

The most common optical thin film design technique is certainly refinement. It is used successfully to generate conventional homogeneous multilayers as well as inhomogeneous, or graded index, systems [1]–[3]. The latter have been found to be useful not only for their unique optical properties, but also as an intermediate stage in the design of conventional multilayers [4]. Another successful approach in inhomogeneous thin film design is based on the use of Fourier transforms [4]. It is sometimes classified as a synthesis technique because, contrary to refinement, it requires little knowledge of a suitable starting point. Typically, it converges quickly and provides useful insight into the problem. However, its accuracy tends to be limited in regions of high reflectance, due to approximations made in the theory. The lack of the speed of standard refinement techniques and/or their reliance on a good starting design are limitations in design problems involving a large number of parameters. Inhomogeneous systems often fall in this category. Special implementations are needed to design such systems [5]. In this work, we describe an efficient algorithm for the design of inhomogeneous films. This algorithm is based on the exact theoretical formulas.
Application of the quadratic programming approach to the design of optical coatings
Authors: Tikhonravov Alexander V. , Popov Konstantin V.
Published: February 2023

A general approach to the synthesis of optical coatings is connected with the optimization of the merit function estimating the difference between actual and target spectral characteristics [1,2]. The merit function is typically non-convex and has a great number of local minima These features make more difficult optimization of the merit function with the help of standard optimization routines. The reduction of the exact non-convex optimization problem to an approximate problem of quadratic programming allows to get out of the difficulty. The quadratic programming problem has an unique solution and can be easily solved due to its convexity. This idea was successfully applied to the design of antireflection (AR) coatings at normal light incidence [3]. In present paper it is generalised for the case of AR coatings at oblique light incidence. The quadratic programming approach provides fast algorithm for the synthesis of AR coatings in wide spectral and angle of incidence ranges.
Design of double reflecting interferential mirror
Authors: Dinca Andreea , Trifan M. E. , Lupei V. , Dinca M. P.
Published: February 2023

The double reflecting interferential mirror presented here are designed to work at λo = 1.064 μm in a medical YAG:Nd laser system at 45° oblique incidence, in unpolarized light.
Implementation of a Numerical Needle Method for Thin Film Design
Authors: Sullivan Brian T. , Dobrowolski J.A.
Published: February 2023

There is a need for different thin film design techniques. Different methods are often required for the solution of different types of problems. A very powerful thin film design procedure, called the needle method, has been developed by Tikhonravov et al.1-8 This method allows new layers to be added to an existing multilayer solution. Hence, it can be used both to refine a starting design that is a good approximation of the desired performance or to synthesize a solution from the start. This technique can be used for oblique angles of incidence, any polarization and with absorbing materials.
The Influence of the Small Losses in Layers of the Thin-Layer Periodic Structures on its Characteristics.
Authors: Kozar' A.V. , Putrina Ye.V.
Published: February 2023

Under Thin-layer Interference Structures (TIS) [1,2] we'll understand antireflection systems with specific optical and structural properties, to the fundamental of which we can attribute the invariance of amplitude characteristics and total optical thickness of the structure on the number of periods and an opportunity of synthesis of such antireflection structures with layers' thicknesses significantly smaller than λ/4.
A Model for Calculation of the Mask Function in Thin Film Coating
Authors: Ling Kow-Je , Shao Kungchi , Lee Chao-Kuo , Lee Jin-Su
Published: February 2023

Thin film coating has found wide applications in optical systems. One of the main requirements an optical thin film must meet is its uniformity. To achieve the demanded uniformity, conventional efforts include special design of the vacuum chamber configuration [1], use of the masks [2], etc. Masks have also been utilized to coat non-uniform films [3]. In principle, a film of arbitrary thickness distribution can be made with an appropriate mask. Usually the shape, the size and the position of the mask are determined empirically. We presented a model to calculate the film thickness and/or the mask function.
Surface roughness characterisation of Au thin film by Spectroscopic Ellipsometry, Grazing x-ray reflectance and Scanning Tunnelling microscopy
Authors: Boher Pierre , Stehle Jean Louis , Houdy Philippe
Published: February 2023

Gold thin films of various thicknesses have been evaporated on silicon and aluminium nitride substrates in the same conditions in order to test the substrate influence on the surface roughness and physical properties of the films.
Absorption Changes in Single Films of Titanium Dioxide and in Titanium Dioxide/Silicon Dioxide Multilayers
Authors: Song Dar-Yuan , Macleod H. Angus
Published: February 2023

Titanium Oxide film produced by reactive electron beam evaporation typically have a columnar microstructure1,2,3,4,5. The optical performance of such films often varies due to the absorption of water vapor. Since water is transparent in the visible region it might be expected that the changes there would be reasonably free of absorption. We report here two methods that have been investigated where significant changes in absorption occur. When the environmental changes cab be reversed, the absorption is also reversible.
Antireflection Coating for Diffractive Optical Elements (DOE)
Authors: Wang Ran-Hong Raymond , Weed Cheryl , Licherdell Bernie J.
Published: February 2023

The antireflection coating of diffractive optical elements (DOE) using IAD (ion assisted deposition) and conventional deposition process will be presented and compared in this report. Results showed that the coating surfaces were damaged and cracked using IAD process with 30 ev ion energy for multilayered and single layer design. However, the single layer convention cold deposition process on DOE was achieved successfully without damaging the surface or changing the transmission wavefront, which was found to be .134 λ before and after coating for the DOE standalone doublet component. On the multi-level phase DOE, the transmission wavefront was .078 λ and 0.094 λ before and after coating respectively. As observed the surface properties of DOE coating were highly related to deposition temperature, evaporation parameter, and coating tooling.
Diamond Coated Copper Optics
Authors: Wagal S.S. , Spence J. H. , Jacobs T. L. , Pearson W. M.
Published: February 2023

With the use of increasingly high power CO2 lasers for material processing applications, parabolic copper mirrors are replacing transmitting optics because of their ability to withstand higher power without sustaining damage. Since copper optics are quite expensive, a protective coating of Molybdenum is presently used to increase the life of these delicate copper optics. SI Diamond Technology has found that copper optics coated with Amorphous Diamond Coating (ADC) have a longer lifetime, and perform better than the same optics coated with sputtered Molybdenum.
Study and Fabrication of V2O5 in Electrochromic Devices
Authors: Yue-guang Zhang , Hua Guo , Yong-hong Ye , Xu Liu , Pei-fu Gu , Jin-fa Tang
Published: February 2023

There is growing interest in the development of materials and devices that can be used for electrochromic "smart windows".[1] Up to today, most of EC devices include a counter-electrode(CE) layer. This CE layer should have such characteristics: the mixture conductor of ions and electrons. In transparent EC devices, it also should have little absorption. In our Lab, we use V2O5 as CE layer.
Smart Windows Based on Electrochromic Coatings
Authors: Hua Guo , Yong-hong Ye , Yue-guang Zhang , Xu Liu , Pei-fu Gu , Jin-fa Tang
Published: February 2023

Recently, smart windows encompassing optically switching electrochromic materials have become the focus of a great number of studies owing to their potential application in automobiles and buildings for improved energy management.[1][2] The optical modulation occurs via the reversible formation of an intermediate compound upon the insertion or extraction of ions and electrons.
A Four–layer Solid–state Electrochromic Device
Authors: Yong-hong Ye , Pei-fu Gu , Xu Liu , Jing-fa Tang , Hua Guo , Yue-guang Zhang
Published: February 2023

Many researches have been performed on the electrochromic devices for various applications. The phenomenon of electrochromism is reversible color change in a material caused by an applied electric field or current. Such devices typically have a five–layer construction. We report a novel four–layer electrochromic device in which the ion storage layer and the ion conductor layer were replaced with a film of AI2O3.
A metal oxide approach for production of selectable absorption, enhanced contrast, anti-reflection coatings for the display market
Authors: Laird Ronald E. , Wolfe Jesse D. , Carniglia C.K.
Published: February 2023

Anti-Reflective (AR) coatings are widely used to reduce unwanted reflections from cathode ray tubes and flat panel displays. Enhanced contrast anti-reflective (ENCORE) coatings produced using one or more absorbing layers in the coating design, are used to improve the image contrast to the viewer. Typical absorbing materials being used in the market today are nitrides of titanium (TiN) and zirconium (ZrN). Problems are encountered using these materials because they result in high absorption levels, and do not give visually neutral transmission.
Inhomogeneity control for titanium dioxide films by ion assisted deposition method
Authors: Takagi Itaru , Ogura Shigetaro
Published: February 2023

Because of the porosity existing within homogeneous films deposited by conventional electron beam gun, they are well known to have spectral shifts after deposition (aging effect). Inhomogeneous films also show dynamic changes such as spectral shifts and stress changes induced by water sorption during and after film deposition. The related structure models for both of homogeneous and inhomogeneous films, which explain these behaviours have been proposed and examined(1). To overcome these effects, various ion based processes such as ion assisted deposition(IAD)(2), and ion plating(IP)(3), have been extensively used in recent years.
Shift free interference coatings deposited with plasma ion assisted deposition
Authors: Zöller A. , Götzelmann R. , Matl K. , Cushing D.
Published: February 2023

The temperature stability of optical coatings becomes more and more important. Especially for telecommunication applications the requirements are very stringent. Since the number of channels of wavelengths increases and the wavelength distance between the channels decreases, it becomes more and more difficult to separate one wavelength channel from the other [1].
Process-Related Thickness Variations in Spin-On Interference Filters
Authors: Birnie Dunbar P. , Manley M. , Zelinski B. J. J. , Melpolder S. M.
Published: February 2023

Optical interference filters can easily be fabricated from high and low index transparent coatings using a number of different processing routes. One inexpensive method for depositing oxide coatings is through spin-on chemical routes [1-3].
The role of interfaces and bulks in the energy balance of a thin film multilayer
Authors: Amra Claude
Published: February 2023

Optical coatings have sub-micrometer thicknesses that cause interfaces and bulks to play an equivalent role in their optical energy balance. At low-loss levels for instance, both absorption and scattering may originate from interface and bulk effects, including geometrical and chemical aspects such as roughness, inhomogeneity, transition layers and impurities… Moreover, these imperfections may result from random or discrete processes that require different characterization tools. At last the tools of characterization should provide multiscale parameters (from the macroscopic to the microscopic) in order to predict the balance of a multilayer under optical power at any wavelength.
Multiscale roughness in optical multilayers
Authors: Deumié C. , Albrand G. , Richier R. , Cathelinaud M. , Amra Claude
Published: February 2023

In the last Tucson meeting, we showed that the macroscopic roughness spectra measured with light scattering at visible wavelengths were perfectly extrapolated at high spatial frequencies by microscopic roughness spectra measured with Atomic Force Microscopy1. These results have been largely confirmed by numerous experiments2,3 and allow us today to characterize thin films microstructure from a macroscopic to a microscopic scale.
Antireflection and high reflection coatings for excimer laser applications
Authors: Novopashin V.V. , Levchuk E.A. , Kolodgy G. Ya. , Tyrin. V.S.
Published: February 2023

During the last years a grate interest arise to uv-lasers. This interest due to their applications in various fields of electronics and medicine. In this paper we present the results of fabricating dielectric films with high resistance to laser radiation at 193, 248, 266, 355 nm [1].
Optimized grating coupler for second-harmonic generation by ZnS thin films.
Authors: Akhouayri H. , Enoch S.
Published: February 2023

Second-harmonic generation and others quadratic effects have attracted a great interest in the past few years. The renewal of these experimental and theoretical studies is essentially focused on cascaded χ(2) effects. Our aim here is to concentrate on corrugated Zinc Sulfide thin film and take the advantage of the strong confinement of the resonantly excited guided waves. Surprisingly, dielectric thin films have not been intensively studied for their nonlinear optical properties as was be done for polymer thin films.
Mechanical stress of TiO2 and MgF2 thin films and their multilayers deposited by plasma ion assisted deposition in Leybold APS vacuum system
Authors: Atanassov George , Turlo James , Fu Ji Kai , Dai Yi Sheng
Published: February 2023

To explain the tensile behavior of the crystalline dielectric and metal films, today mostly the grain boundary model is applied [1]. According to the model, the interactions across the grain boundaries in the polycrystalline dielectric films play a vital role in the development of film stress. Lattice relaxation forced by the energetic interaction between grain boundaries presents an elastic deformation, which expresses itself microscopically as observable mechanical stress. When two grains are attracted by van-der-vaals force to each other across the gap formed in the deposition process a local tensile stress field arises. If the gap is small enough so that repulsion between the grains takes place then compressive stress field may arise. Ion bombardment during thin film deposition enforces densification processes in the films by reducing the gaps, which consequently results in less tensile and even compressive stress. Absorption of residual gases by the film in the vacuum chamber or in air can play a vital role in the stress development, causing a reduction of the surface free energy and hence the tensile stress with possible transformation to compressive stress.
Reduction of light scatter from reactively sputtered oxide films by ion bombardment
Authors: Reicher D. W. , Sobczak J. , Black J. P.
Published: February 2023

Reactive D.C. magnetron sputtering is a physical vapor deposition method that produces films which are optically and mechanically superior to evaporated films in several respects.1,2 This technique has the advantages of a higher deposition rate and fewer deposition parameters than ion beam sputtering. In this investigation it will be shown that by ion bombardment during deposition, the scatter and absorption of zirconia, and the scatter of silica films can be decreased. A decrease in scatter from zirconia/silica high reflectors was also observed.