bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic and Magneto-optical Properties of TbFeCo/Pt and TbFeCo/NdCo Multilayers
Authors: Itoh Y. , Suzuki T.
Published: February 2023

The optimization of novel materials for short wavelength magneto-optical recording is key for future high density recording. TbFeCo amorphous films currently used exhibit a substantial reduction in Kerr activity with decreasing wavelength [1], and therefore, it is desirable to enhance it by adding some element. Polarized Pt atoms are known to enhance the magneto-optical effect at short wavelengths, as demonstrated in Co/Pt multilayers [2]-[4], NdFeCo films also show the increase of the Kerr rotation angle at such wavelengths [5], [6], Accordingly, TbFeCo films containing Pt or Nd are potential candidates for future short wavelength recording media. However, very little systematic studies have been carried out to examine the effect of Pt in rare-earth transition-metal (RE-TM) amorphous films [7], [8]. And Nd-TM alloy has a problem that the films generally show in-plane magnetization, although the high perpendicular magnetic anisotropy must be taken into consideration in practical use. In order to achieve high Kerr activity at short wavelengths with a high perpendicular anisotropy, multilayers such as TbFeCo/Pt and TbFeCo/NdCo were fabricated. The present study aims to understand the roles of Pt and NdCo layer in TbFeCo on both magnetic and magneto-optical properties.
New layer structure of phase change optical disk free from the initialization process
Authors: Ogawa S. , Takeguchi K. , Morimoto I.
Published: February 2023

Phase change media have to be initialized prior to recording. Initialization for phase change optical disks involves crystallization of as-deposited amorphous recording films. An initialization-free technology will lead to a low production cost which is very important for commercializing phase change optical disks. Several methods had been proposed for reducing the process time for initialization.1) For Ag-In-Sb-Te recording materials, an initialization-free procedure had been proposed by Takahashi et at. in 1997.2) The other alternative recording material GeSbTe has a higher recording speed than that of the Ag-In-Sb-Te. To our knowledge, no work has been reported on an initialization-free technology for the phase change optical disk with a GeSbTe recording layer. In this paper, we propose a new layer structure of phase change optical disk free from the initialization process.
New concept of phase change recording free from the initialization process
Authors: Ogawa S. , Takeguchi K. , Morimoto I.
Published: February 2023

A five-layered phase change optical disk, which has a thin metal layer between the substrate and the lower dielectric layer, has been proposed by Kobori et al (1) and Nishimura et al (2). The light absorbance in a recording layer is able to be controlled by using the five-layered structure, so as to improve overwriting jitter at high linear velocity. The thickness of the lower dielectric layer of the five-layered disk was designed so that the reflectivity of the amorphous state (Ra) was higher than that of the crystalline state (Rc), thereby the absorptivity of the crystalline state (Ac) can be kept larger than that of the amorphous state (Aa). But the low reflectivity of the initialized state, that is crystalline state, causes servo instability.
A New Model For Optimization Of Erasure Time In Reversible Optical Memories Including Shape Factor, Temperature and Mass Effects On Incubation Time In Various Nucleation Processes
Authors: Nagpal Swati , Bhatnagar P.K. , Pathak Pankaj
Published: February 2023

Work is in progress for improving the switching times of erasable as well as DOW type of optical memories. As it has been already established that the erasure time (a→c) is dominated by incubation time (τ), hence τ needs to be explored more in depth [1]. In the present work the mass, molecular diameter and density effects have been shown in addition to the temperature effects. The earlier calculations could only estimate the value of τ using arrange of critical radii values [2,6], whereas the present model can be used to calculate the exact values of critical radii using shape factor calculations for grain boundary, grain edge and grain comer nucleation separately. Knowing the material parameter of a system, one can calculate variation of x with temperature, mass or composition.
A Monolithic Confocal Optical Pick-up Device
Authors: Narui H. , Doi M. , Nakao T. , Sahara K. , Matsuda O.
Published: February 2023

To obtain a small and reliable optical pick-up capable of being mass-produced, it is important to integrate optical components in a small packaged device. Recently several authors reported hybrid integrated optical pick-up devices, using a micro-prism and holograms [1]. However there are few reports of monolithic optical pick-ups [2]. Based on the novel optical device previously reported [3], and we fabricated a monolithic optical pick-up in combination with a plastic lens and an actuator.
New types of the optical mask to suppress the adjacent track crosstalk
Authors: Ooki Hiroshi , Otaki Katsura , Ishii Koichiro
Published: February 2023

To achieve a narrower track pitch, say ,0.85 μ m which is proposed for 5.2Gbyte/130mm MO, suppression of the adjacent track crosstalk (ATC) will be one of the key technology for the optical memories. Several methods have been proposed for the suppression of the ATC such as land/groove recording. Dobashi 1) et.al. have proposed one method to reduce the ATC by inserting a shading band in the optical path. Shimano 2) et. al. have also reported that optical filterings are effective to reduce the ATC without degradation of the signal amplitude of the center track. Although their filters can indeed reduce the ATC from the long marks such as 6T,7T and 8T, the ATC relatively increases after the insertion of the filters with regard to short marks such as 3T and 4T. In this paper, we propose new types of the optical mask which can reduce the ATC from the long mark signals with suppressing the increase of the ATC from the short mark signals to negligible level.
Hologram Fixing in Lithium Niobate by Laser Heating
Authors: Haskal Haim M. , Sy Maida , Fiddy Michael A.
Published: February 2023

Volume holographic storage in photorefractive crystals has been the subject of intensive research over the past decade under government and industry sponsorship. Three-dimensional memories hold the promise of combining very large capacities (>1Tbyte) with very high data rates (>1Gbit/s) and very short access times (<1ms).
Reduction of cross erase in phase change media
Authors: Okubo Shuichi , Kubogata Masayuki , Okada Mitsuya
Published: February 2023

The reduction of cross erase in phase change media is crucial to the achievement of land/groove recording with a track pitch of less than 0.6 μm. The method of cross erase reduction that we report here have succeeded without the use of deep groove substrates [1].
Flat Lapping Revisited*
Authors: Brown N. J.
Published: February 2023

This paper is an updating and continuation of an earlier paper, Annular Lapping of Precision Optical Flatware. Restricted to precision lapping and to machines that can move parts in pure translation across a viscoelastic medium, it will discuss: the availability, cost, and cost effectiveness of the process; the pure translation principle; and behavior of the viscoelastic medium; current thinking on control; the new generation or large laps in planning; and near flat spherical lapping. It is geared to extending the technology with particular emphasis on large parts.
Fabrication Technology for Advanced Space Optics
Authors: Hamill Doris
Published: February 2023

When it is finally launched in 1981, the Space Shuttle will provide relatively easy access to the hard vacuum of space. From there we will have an optically stable medium through which to look up at the stars to satisfy our scientific curiousity, or down at the earth to satisfy our defense needs. But exploiting this new optical platform poses unparalled challenges for optical fabrication technology. Mirrors must be capable of operating in a thermally hostile environment. They must be as light as possible to meet launch vehicle weight constraints, yet stiff enough to hold their figure once released from gravity's influence. The field of view requirements will demand that mirrors be highly aspheric. Mirrors which exceed the Space Shuttle's four meter diameter capacity will have to be sent up as segments and assembled in orbit. What is more, defense requirements will mandate that the normally leisurely pace of optical surfacing be significantly accelerated.
Use of Tangent Mounts for Diamond Machining Optics
Authors: Arnold J. B. , Steger P. J. , Yoder R. C.
Published: February 2023

A fundamental requirement for precision diamond machining is the use of a proper part support technique. Various fixturing techniques have been used during diamond machining to minimize or duplicate the strain that the part will be subjected to during use. These techniques include: three-point support, one-point support, potting, collet chucking, and vacuum chucking. During the production of a 15-inch-diameter reflaxicon, its two components, a ring axicon and center axieon, were assembled in tangent mounts and supported using a vacuum chuck. The tangent mount reduced the fixturing strain by increasing the distance the strain must propagate through, and by increasing the rigidity of each component relative to the spindle fixture. Non-flatness error of approximately 40 μin (1 μm) in the support flange of the tangent mount resulted in less than 2 μin (.05 μm) distortion in the optical surface.
The Problems and Pitfalls of Buying Optical Coatings
Authors: Loveridge Ronald C.
Published: February 2023

Optical coatings have long been considered a rather elusive product to characterize and understand. The types of coatings available are legion. Their complexity and the vast number of factors that affect the final product produce an air of mystery that cause some individuals to consider optical coatings as a rather expensive "black art". Coating engineers are thought of as modern day wizards who have traded their black cauldrons for gleaming coating chambers.
On-Site Manufacturing of a Large Mirror Blank
Authors: Lewis William C.
Published: February 2023

Coming's association with astronomical telescope mirror substrates began in 1931, when attempts to make the 200" blank for Mt. Palomar of fused natural quartz had proven unsuccessful, and Corning was approached about attempting to make it of one of their still relatively new PYREX® brand glasses. The rest is history.
Fabrication of a Large Off-Axis Paraboloid
Authors: Parks R.E. , Crawford R.C.
Published: February 2023

We discuss the fabrication and testing of a 1.4 meter off-axis parabola made as an off-axis section. This approach, though non-conventional, is justified on the basis of cost. Although the approach looks very cost effective, the fabrication of the off-axis paraboloid is still a difficult task. An approach is discussed which will lead to the easiest possible fabrication technique. We then proceed step by step through the entire fabrication process stressing those areas of fabrication and test which have been particularly fruitful and also pointing out those areas in which we have had difficulty.
Computer Controlled Polisher Demonstration
Authors: Jones Robert A.
Published: February 2023

A recent effort was conducted to demonstrate the efficiency of the computer controlled polisher process. A computer program was written which predicts the surface figure progress for each polishing cycle. A 1.8 meter lightweighted glass mirror was polished for four cycles using the prediction program to provide an estimation of expected surface figure improvement. The polishing activity improved the mirror surface from an RMS figure error of 0.16 waves to 0.04 waves. Even though this figure improvement lagged the predicted results due to metrology uncertainty, the rapid error correction demonstrates the computer controlled polisher to be a highly valuable manufacturing tcol.
Integration of Thin Film Coatings Into Optical Systems
Authors: Matteucci John , Baumeister Philip
Published: February 2023

Some factors that influence the choice of thin film coatings in an optical system are summarized.
Affordable Interferometers
Authors: Bacevic John
Published: February 2023

Summary not available
A study on the vee block refractometer
Authors: Campitelli Enrique J.
Published: February 2023

The vee block (Hilger-Chance) refractometer1,2 is to be preferred in the optical shop because of its good precision, because it measures the bulk and not the skin refractive index, and for the little work needed in the preparation of the sample. The latter is its most important feature.
Interferometric Standards for the Optics Shop
Authors: Loomis John
Published: February 2023

Summary not available.
Cleaning a Spatial Filter Lens in its Assembly
Authors: Guntram S.
Published: February 2023

Summary not available.
Methodology of Determining Price for Manufacturing Optical Systems
Authors: Lepman R. D.
Published: February 2023

Summary not available.
Working With Beryllium
Authors: Piccolo Stephen K.
Published: February 2023

Beryllium metal and all of its industrially used compounds have been documented as causing disease.
Precision Radius and Spacing Measurement Using Interferometric-Gauge Bar Techniques
Authors: Slomba A.F. , Davis J. J.
Published: February 2023

A technique is described for measuring the absolute radius of curvature of spherical optical surfaces by using a calibrated gauge bar and interferometry. A description of test arrangements, experimental considerations, and results of a particular measurement are presented. Accuracies of the order of a few parts per million are practicable when the technique is used.
On Making Dual-Function Telescope Pairs: An Application of Computer-Directed Polishing (Without the Computer)
Authors: Vandermeer H.W.A. , Valleli P.A.
Published: February 2023

Two sets of identical Cassegrainian telescope pairs have been manufactured for a space navigation device. A simplified wear program was utilized to grind and polish the primary mirrors which proved to be beneficial. For final aspherizing, however, the calculation process for residual errors proved to be too time consuming and could not handle asymmetric errors. New tooling techniques were tried and found to be advantageous. The master opticians and engineers gained new insight into the computer directed polishing process. The optical system configuration and design requirements are described.
Optics for a "Far-Afield" Environment
Authors: Nitchie Francis R.
Published: February 2023

Factors involved in installation, use, and maintenance of optics in "remote" locations and adverse environments are discussed in terms of what should and shouldn't be designed and built to make life easier for those who are destined to use and maintain them. Factors requiring consideration include, but are not limited to, distance from competent assistance, the limited competence of locally available assistance, the limited quantity and nature of test and handling equipment at many field sites and the less-than-ideal environment in which many systems must survive and produce hopefully ideal results.
Piezo Stepping and Fine Positioning Control for Optical Instruments and Processes
Authors: Gee Anthony E.
Published: February 2023

Where an optical component is to be automatically positioned either during fabrication or in a working instrument, an active optical-mechanical interface is required. For direct electro-mechanical displacement control to within sub-micron accuracy, piezo-electric actuators may be utilised and their range extended by 'microstepping' action.

An arrangement is described in which piezo-electric actuator elements are employed for step generation and for fine automatic feedback control between steps. Prior to each step the residual error correction in the fine control element is transferred to the stepper element thereby accommodating cumulative corrections of errors of run.
Coating and Metrology of a 90° Phase Shift Coated Cone
Authors: Guha J. K. , Southwell W. H. , Mickish R. A. , Martin J. L. , Johnson C. , Bobb M. , Ready H. , Chambers J.
Published: February 2023

A diamond turned aluminum cone was coated with a multilayer dielectric coating which was designed to produce a 90° phase shift at 10.6 μm between the S and P components on reflection.
The Advantages and Pitfalls of Diamond Single-Point Machined Optics
Authors: Decker D. L.
Published: February 2023

Diamond machining can be an expeditious production method and can yield superior optical surfaces for some applications. However, diamond-machined surfaces are not equivalent to conventionally polished surfaces, and only by understanding the distinction can effective use be made of either method of fabrication. Diamond single-point machining is a "capital-intensive" fabrication method involving super precision, air-bearing, numerically controlled lathes. For the production of axisymmetric aspheric surfaces, this method offers a deterministic approach, and for sufficiently large quantities can be cost effective.
Optical Phase-Measurement Microscope for Surface Analysis
Authors: Koliopoulos Chris L. , Wyant James C.
Published: February 2023

An interferometric microscope system is described which can be used for surface structure analysis. The system is based upon an optical phase modulation technique, described below, which obtains surface heights at each detector point to a precision of a few Angstroms, with a lateral resolution of approximately 2 microns. The system is comprised of a Mirau interferometer mounted on a standard microscope, a linear 256 element CCD array, a Z-80 microprocessor which controls the data acquisition and phase measurement calculations, and an HP-85 micro-computer. At the operator's option the HP-85 can subtract average height, tilt, and focus from the surface height data; generate a surface profile, a histogram of the surface height distribution, and form the autocovariance of the surface profile. The operator can select hardcopy of the plots on thermal paper or x-y plotter output.
Lateral Distortions and Focal Shifts in a Projection Optics System
Authors: LaCoste Francois
Published: February 2023

In the 1;1 microlithography projection mask aligners described by Markle(1) and Offner(2) (see Figure 1), as little as an eighth of a wave figure error on one of the mirror surfaces can introduce over half a micron lateral image distortion, causing unacceptable misregistration of the wafer patterns. Such a figure error can also shift the image focal plane by over four microns, causing a reduction in the useful depth of focus. Because of the geometry of the projection optics, it is difficult to measure the surface figures with sufficient accuracy to predict the distortions and focal shifts. An instrument was built to measure the distortions of the projection optics with an accuracy of 0.06 microns per site. Routine measurements at a large number of sites along the annular field permitted the identification of typical signatures in the distortion curves. In an attempt to correlate these signatures with mirror fabrication problems, typical mirror figures were modelled with a modified optical designers program. It will be shown that an equivalent surface figure can be calculated from the distortion data by a deconvolution operation. The process is used to predict the focal plane shifts (see Figure 2). The method by which these dummy surfaces are calculated, the effects of the type of polynomial approximations on the predictions, and the choice of the location of the surface will be discussed. The calculated shifts will be compared to the measurements, and the benefits for the manufacturing process will be discussed.
Scatter Evaluation of Supersmooth Surfaces
Authors: Stowell W. K. , Orazio F. D. , Silva R. M.
Published: February 2023

Producing optical components with surface smoothness adequate for ring
laser gyros has been a problem for nineteen years. Part of the
difficulty has been measurement techniques. There are few techniques
in use that have the sensitivity to determine the quality of very low
topography surfaces and even fewer which can characterize uncoated
surfaces. The high accuracy ring laser gyro requires optical surfaces
of lower topography than is usually produced except in specialized
laboratories. New measurement techniques are required before the
polishing techniques can be refined to the degree necessary for these
gyros.
Optical Materials and Health Concerns
Authors: Port Eugene A.
Published: February 2023

The health concerns with the materials that are used in the coating industry are a reflection of the health concerns that have occured throughout all of industry. Let's take a look at where much of this concern is coming from.
Gradient Index, Fiber and Integrated Optics
Authors: Moore Duncan T.
Published: February 2023

Modern optical research has led to developments which are dependent on traditional areas of optics. Modern manufacturing techniques for optical fabrication have included the addition of aspheric surfaces and gradient index components. In addition, conventional optical methods can be used to design guided wave optics devices and fiber optics components. Each of these represents a change for the lens designer and introduces an additional complication for the optical fabricator. Each of these topics will be discussed in some detail.
High Volume In-Process Testing of Spheric Surfaces
Authors: Gallagher Merle G.
Published: February 2023

During the last decade, production technology for aspheric lens manufacturing has greatly expanded, resulting in an increased requirement for interferometric lens testing capability. One solution has been the development of a Dual Beam Interferometer Testing Station coupled to a computer data evaluation center.
Producing a Prototype Photographic Lense for the Routine Testing for Eye Defects in Very Young Children
Authors: Glece Hill R. F. , Walter S. D.
Published: February 2023

A photographic system evolving from Foucault's test, utilizing a ring - flash light source to detect eye abberations or squints, suitable for unskilled users.
Joint Logistics Command Adhoc Group Study on Precision Optics Products Base
Authors: Winner Clark , White Rod
Published: February 2023

Summary not available
Novolac As Stain Protective Film During Optical Glass Fabrication
Authors: Hed P. Paul
Published: February 2023

Stains on polished surfaces are troublesome because they occur after the polishing process is complete. Sometimes the stains become apparent only after thin film deposition, when the additional coated material makes them visible. The major cause of staining and dimming is dihydrogen oxide (i.e., water), the same liquid that is almost indispensable for glass polishing. Because water and aqueous solutions are present during most phases of optical fabrication, polished surfaces should be coated with proper protective film at all times. In addition to being water resistant, the protective film should be rigid enough and not too acidic. Flexible films will cause blocked elements to shift during polishing while acidic films, such as some pitch or rosin mixtures, will contribute to staining.
Chemical Treatment of Silicate Glasses for Producing Anti-Reflection Surfaces
Authors: Wirtenson G. Richard , Thomas Ian M. , Brown Norman J. , Wilder John G.
Published: February 2023

This paper will present a brief summary of the developments in progress for chemical AR treatments of BK7 and SiO2 at Corning Glass, Schott Optical, Westinghouse and LLNL in support of the LLNL Laser Fusion Program. Details of several of these processes are tied up with patent applications or are at some point considered proprietary, but sufficient information can be revealed to show the trends of the work in progress and the potential for specific applications.
Lapping & Polishing with an Actively Stressed Lap
Authors: Angel J. R. P. , Parks R. E.
Published: February 2023

A method is proposed for polishing fast aspherics with a lap whose shape is continuously changed under computer control as it moves over a rigid mirror blank. The required changes of radius, astigmatism and coma in a circular lap are made with edge bending levers and tensioning members with screw actuators.
Results of a Survey on the Needs For Optical Standards
Authors: Olson Valerie F.
Published: February 2023

The Standards Committee of the Optical Society of America came into full "standing" committee status in 1980. Subsequently, a long range plan for committee activities was drafted. This plan included an initial assessment of the community's perception of the need for uniform optical standards. It was decided that a useful mechanism would be to survey the various segments of the industry such as users, manufacturers, government labs, industry and academia by means of a questionnaire.
Scratch and Defect Measurement
Authors: Baker L R
Published: February 2023

The stringent performance requirements of a number of systems involving optics and electronics in, for example, mass information storage, high power laser optics, aspheric surface generation, integrated optics and solid state circuitry, have tended in recent years to accentuate the need for rigorous control of surface quality. The effect of a surface imperfection, such as a scratch or dig or even surface contamination, can be either cosmetic, as would be the case with a spectacle lens or the front component of a camera lens, or functional if it resulted in a reduction in the useful life or power output (1) of, say, a high power laser system or reduced the yield of devices produced from a semi-conductor wafer.
Standardization of Radii of Curvature in Lens Design
Authors: Kreischer Cody B.
Published: February 2023

Research was performeddetermine the feasibility of using standard radii of curvature in lens design. This research served as the basis for a Master's thesis at the Optical Sciences Center, University of Arizona, with Prof. Robert R. Shannon acting as thesis advisor. Condensed results of this study are given here.
Interferometric Lens Testing to λ/40 at λ=0.442μm
Authors: Berman Joann , Hunter George C. , Truax Bruce E.
Published: February 2023

This paper describes the construction of an interferometer system capable of measuring precision (λ/10 peak-to-valley) microlithographic lenses in transmission. The project required special hardware and Zernike analysis software.
Fabrication and Testing of the Nova 77 cm F/4 Focus Lens
Authors: Meckel Julius
Published: February 2023

As the optical industry is changing, based on the demands of our ever moving technology and responding to these new requirements, innovation and the development of greater control and entirely new fabrication and test techniques are necessary for any successful organization. Optical fabrication techniques formerly left entirely to the skill and personal innovation of the optical craftsman are now moving away from traditional practices and are getting more engineering attention than ever before. The emergence of readily available electronic technology in convenient numerical control devices and the use of the laser as a light-source in test applications, have brought about an, as yet slow, but definite revolution. This does not by any means curtail the role of the optical craftsman, quite to the contrary, he now has at his disposal more control and more metrology to better apply his masterly skills to achieve the sophisticated accuracy demands imposed so routinely on our industry today. Aspheric surfaces, only a few years ago, applied refractively only in illumination systems, are now moving rapidly into universal optical applications. Designers are enjoying more freedom in being able to utilize this tool with the confidence that the more sophisticated optic they design can indeed be manufactured. The application presented here is an attempt to show current manufacturing approaches for a high accuracy single element aspheric focus lens for the LLNL laser fusion program.
Cooperation Between the Lens Designer and Lens Manufacturer
Authors: Muffoletto C. Verne , Goodell John B.
Published: February 2023

The lens manufacturer and lens designer should communicate throughout the entire lens manufacture cycle which includes design, fabrication, testing, delivery and often, post-delivery. In the early design stages the designer must attempt to choose reasonably available optical materials which have suitable chemical, physical and optical properties, and which are workable. The manufacturer should not be forced to work with configurations requiring inordinately tight tolerances. An example is two extreme lens shape factors which balance each other in almost unstable equilibrium.
Data Reduction for Phase Shift Interferometry
Authors: Ai Chiayu , Wyant James C.
Published: February 2023

Phase-shift interferometry (PSI) techniques have been widely used in modern phase-measurement instruments. The PSI technique is based on varying the phase difference between two beams in a known manner, and deriving the initial phase using three or more intensity measurements. The most common way to vary the phase difference between two beams is to apply a voltage to a piezoelectric (PZT) transducer upon which the reference mirror is mounted. The voltage applied is a ramp voltage or a step voltage with equal period and equal increment.
Absolute Measurement of Flat Mirrors in the Ritchey-Common Test
Authors: Küchel F.M.
Published: February 2023

The absolute determination of the shape errors of an optical flat is a classic problem in the interferometric measuring technique. The use of the surface of a liquid as a flatness reference is only practicable in exceptional cases /1/. Various authors have therefore proposed further solutions /2,3,4/ in which, however, the error curve is either only obtained along a section (with the traditional three-flat method) or in terms of a polynomial approximation, e.g. by Zernike polynomials. In the measurements of high spatial resolution made possible by electronic phase shifting interferometry, preference should be given to a local interpolation method over the global polynomial interpolation in order to ensure that the original information density of the raw data is also retained in the subsequent evaluation.
An Overview of the Fabrication Process
Authors: Fantone S. D.
Published: February 2023

This presentation is concerned with the general process of optical fabrication and serves as an introduction to the talks which follow. The intent is to provide a basic understanding of the approaches which are used to fabricate the wide variety of optical materials available today.
Optimum Distribution and Tolerance of Axial Point Supports for Structured Telescope Mirrors
Authors: Wan D. S. , Angel J. R. P.
Published: February 2023

Gravity will produce non-negligible deformation in large mirrors when it is acting in the direction of optical axis. An optimum support pattern can be found to minimize the self weight deformation. The approach of this problem provided the support pattern has adequate symmetry can be obtained from the solution of Nelson and Lubliner1 in which the mirror is assumed as a thin circular flat disk. For mirrors with internal honeycomb structure the support points are constrained by the symmetry of structure and cannot be placed in rings, as is usual for large mirrors. Given a particular structure alternative symmetrical placements of the supports were explored, and solutions obtained for the fraction of weight supported by each point to get the minimum deformation. Figure 1 shows the deformation of an optimum supported honeycomb mirror with the rib pattern shown by Angel and Woolf2. The support efficiency is 2.07 × 10−7 which is close to an ideal triangular grid with the same number of support points. Scaled to an 8-m diameter and 60 cm thickness disk it corresponds to surface rms deviation of .006μm. To study the force tolerance we choose errors of the force at each support point according to a Gaussian distribution function. Figure 2 shows the deformation of this kind of support in which the standard deviation is 0.055% of the nominal force. The support efficiency degrades to 5.08 × 10−7 in this case. For comparison, Figure 1 and Figure 2 have the same gray level.
Ion Beam Figuring for Rapid Optical Fabrication
Authors: McNeil J.R. , Wilson S.R. , Barron A.C.
Published: February 2023

The application of ion beams to figure optical surfaces has been examined for a number of years by several groups of investigators. The technique is generally intended to perform final figuring on surfaces which are several optical waves from what is desired. However, until recently the technique has not offered promise to be an efficient, practical method to figure optics.
Comparison of Bare Silver and Bare Silver on Copper Mirrors
Authors: Kimura W.D.
Published: February 2023

Bare silver provides one of the highest reflectivities possible in metal mirrors at visible wavelengths. However, its widespread usage is hampered by its tendency to quickly tranish upon exposure to air. One recent effort to improve the durability of bare silver mirrors has been to include a copper underlayer beneath the silver.1 Reflectance measurements have demonstrated the improved durability of the silver on copper mirrors, but these measurements have been at normal incidence. This paper compares the absorptance properties of bare silver and bare silver on copper mirrors at angles of incidence from 0° to 89° for both s- and p-polarizations.
Surface roughness of Al-coatings measured by sub-Å sensitive total integrated scattering technique
Authors: Mattsson Lars
Published: February 2023

Quantitative determination of light scattering and surface roughness of Al-films is of primary interest for several reasons. The scatter in reported optical constants of Al-films is often attributed to surface roughness /1/ although no quantitative roughness measurements have been performed. Further, aluminium coatings are extensively used on gratings and mirrors. Applications of these elements are in many cases critically dependent on the scattering level, as in raman spectroscopy and astronomical optics.
Status of International Optical Standards Activities
Authors: Parks Robert E.
Published: February 2023

The International Standards Organization through its Technical Committee 172, Optics and Optical Instrumentation, has been actively working on drafts of optical standards since 1979. In particular, Subcommittee 1, Fundamental Standards is working in the areas of OTF testing, optical drawing standards and environmental testing. Draft proposed standards are presently being published about the theory and practice of OTF tests for copier and 35mm photographic lenses as well as many facets of environmental testing of optics. The optical drawing standard work is about two years behind the other areas but draft proposals will be published in early 1988. Public comment is encouraged and welcomed. Particularly significant is the standardization work relative to optical surface imperfections or beauty defects. Agreement was reached to use a quantitative photometric micro-image comparison device1 to grade scratch type defects and to relate the scratch photometric appearance to chrome on glass line width standards. While it will take several years experience with this method to fully assess its practicality and general utility, initial indications are that the method is clearly superior to qualitative comparison or defect area (DIN) based inspection methods.2
Versatile, High Accuracy Scan Lens Test Bench
Authors: Richard Wayne M. , Parker Glenn A.
Published: February 2023

A scan lens test bench must be adaptable to the wide range of sizes, formats, and wavelengths of scan lenses manufactured today. In addition, it's metrology must be capable of accurately measuring angles and distances for verification of scan linearity. All of the above were carefully considered in the design and fabrication of this bench. Fringe counting interferometry is employed for monitoring linear and angular motions. Attached to a fringe counter via a tangent arm, a flat mirror, pivoting at the test lens' entrance pupil location, is used to accurately deflect the input beam to the desired scan angles within a few seconds of arc. Since the beam deflection is produced with the pivoting mirror, the laser and beam expander optics are stationary. Therefore, virtually any laser and beam expander can be adapted to the setup. This simplifies the selection of desired wavelengths and input beam sizes. Adapter plates facilitate mounting of lenses having a wide range of sizes. Long precision linear slide motions are used to accommodate larger format lenses. The design, fabrication, alignment, and use of this test bench will be discussed.
Float Polishing Of Optical Materials To Produce Super-Smooth Surfaces
Authors: Namba Yoshiharu
Published: February 2023

The demands of super-smooth surfaces have increased gradually in both advanced science and technology fields, for example, mirrors for ring laser gyros, mirrors and windows for high power lasers, UV optics and X-ray optics. The float polishing technology was invented for finish electronic materials ultrafinely without plastically deformed layer [1-3]. Magnetic heads for VCR need the flat and smooth surfaces of small edge radii without damaged layer at the gape opposing faces. More than one hundred million VCR heads have been produced using the float polishing in Japan.
New Optical Glasses for the 80's
Authors: Izumitani Tetsuro
Published: February 2023

Recent data on optical glasses are discussed for the following areas: • New fluorophosphate optical glasses • Molding technology for optical lenses • Glasses for opto-electronics: laser glass, fluoride and chalcogenide glass fibers, GRIN lenses and chalcogenide optical memories.
Fine Grinding Lenses with a Generator
Authors: Duckett Bruce
Published: February 2023

Fine grinding lenses with a generator offers many advantages over diamond pellet or loose emery grinding in certain applications. The advantages and disadvantages of this process are discussed.
Rapid Fabrication of One Meter Ultralightweight Glass Mirror Substrates
Authors: Wangsness P.A.A. , Cannon J.E.
Published: February 2023

To date, most methods of fabricating 1 meter and greater lightweight glass substrates have required extensive labor to achieve the thin ribs necessary for full thickness, low density blanks.1 In this paper progress on the Gas-Fusiontm process tpwards lighter and larger blanks is discussed. Full thickness blanks of 80%-90% lightweighting are discussed. Originally funded by NASA and Discussed in several paper presentations, 2,3 continued research has been internally at Hextek, with additional funds from Ball Aerospace Systems Division. Ribs as thin as 1mm have been achieved in 30cm blanks, producing core densities as low as 6%. The process involves fusing cut tubing between two plates of the same glass by heating in the furnace. At the appropriate temperature the glass is soft enough to achieve a complete welding of the contacting surfaces, eliminating the need for frit bonding required of lower temperature bonding procedures. The Temperature is raised further and a pressurizing gas is distributed among the now sealed tubes. Complete expansion of the tubes produces straight walled fibs with large.fillets and contact surfaces between the ribs and the faceplates. One meter blanks made with the Gas-Fusion^ process require less than two weeks to produce.
ISO Standards for Optical Glasses
Authors: Loomis T. J.
Published: February 2023

Working Group 1 on optical glasses has been working on standards for the hardness of glass and its resistance to weathering and chemicals.
Injection Molded Optics - A State of The Art Review
Authors: Fantone Stephen D. , O'Hagan Terence D.
Published: February 2023

The paper reviews the capabilities and manufacturing methods used to fabricate precision injection molded optics and describes their advantages and limitations.
Coherent Heterodyne Scatterometer
Authors: Gacusan L.Z. , Kwiatkowski S.L. , Sullivan B.J. , Snyder J.J.
Published: February 2023

An instrument has been developed that measures the magnitude of the Bidirectional Scattering Distribution Function (BSDF) employing coherent optical heterodyne detection at 633nm in a Mach-Zehnder interferometer configuration. In preliminary measurements, instrument performance agrees with theoretical predictions and is characterized by diffraction limited resolution, 15 decades of dynamic range and shot noise limited sensitivity. The scatterometer is constructed from readily available components and the instrument configuration can be adapted to measure scattering from objects in transmission or reflection. In the scatterometer, the beam from a commercially available stabilized 3mW He-Ne laser is split into two beams: a scattering beam and a local oscillator beam. The frequency of each beam is individually shifted by separate acousto-optic modulators operating at different drive frequencies. The scattering beam is directed to the target whose orientation is adjustable. The scattered light and the local oscillator beam are combined and directed onto a photodetector where the resulting heterodyne signal is the frequency difference between the two beams. The RF power of the heterodyne signal is proportional to the optical power that is scattered from the target and is polarization-and mode-matched to the local oscillator beam. The combination of shot-noise-limited sensitivity of a heterodyne detector and milliwatt saturation levels of typical photodetectors provides the large dynamic range necessary for accurate measurements of BSDF. Moreover, characteristics inherent to coherent detection systems permit measurements with diffraction limited angular resolution and yield information of the polarization content of the scattered light. Results of BSDF measurements of various surfaces and materials will be presented.
Fabrication of an Optical Heterodyne Profilometer
Authors: George M. C. , Jagannath H. , Reddy B. R. , Perera Gerard M. , Venkateswarlu Putcha
Published: February 2023

An optical heterodyne profilometer was fabricated for the measurement of surface roughness. Briefly, when two beams of slightly different frequencies are reflected from two different points on the surface, the phase of the resulting sinusoidal interference signal is related to the height difference between the two points, whose absolute value is estimated by comparing it with the phase of a reference signal, but no reference surface is involved.1
Systematic Error Sources and Absolute Calibration on Digital Wavefront Measuring Interferometer
Authors: Yucong Zhu , Guoguang Yang , Taihuo Dong
Published: February 2023

A novel digital wavefront measuring interferomater has been developed in our group. TV camera and microcomputer are used to measure the intensities in the interference pattern and synchrously detect the phases by Fourier series method.
Rotational Interferometry for High-Resolution Angle Measurement
Authors: Howard Timothy L.
Published: February 2023

A high-resolution incremental angle encoder based on optical interferometry is described. The basic concept employs a Michelson configuration where one arm of the interferometer is directed tangentially to a reflector moving about the axis of rotation. The resulting optical path difference encodes angular motion as a linear translation of the interferometer fringe pattern, which can be detected and processed by conventional electronics. This instrument possesses a large angular range and very high angular precision which can be adjusted through the length of the lever arm. Design parameters and tradeoffs, error sources, limitations, and results of performance measurements are presented.
The Status of the FAR and APOMA
Authors: Leshne Robert H.
Published: February 2023

The precision optics base prior to the formation of APOMA in 1986 was a fragmented industry composed of optics manufacturers without unified or coherent representation to deal with the problems plaguing the industry.
Optician Training: An Academic/Industrial Partnership
Authors: Novak Robert F.
Published: February 2023

An overview is presented of successful optician training programs in the Rochester area where both Academia and Industry develop and deliver the material together.
Use of a CNC Mill in an Optical Shop
Authors: Grindel Manfred W.
Published: February 2023

The CNC milling machine, previously thought to be restricted to machine shop use, can be an effective device for the shaping of various optical materials to a variety of configurations using the correct cutting speeds and diamond grit cutters.
Update on CNC Curve Generators
Authors: Nielsen Bruce E. , Clarke Fred W.
Published: February 2023

The application of numerical controls and computers to machine tools is today a common place in general industry, and we do not suggest our work in their application to a curve generator represents any sort of a technological breakthrough. But in the optical industry the trade-off of costs and benefits have seemed to preclude consideration of expensive electronics except in the "corporate giants" end of the industry.
Problems with Polishing and its Quality Assessment
Authors: Fiedler K. H.
Published: February 2023

The matching of tool and workpiece is known to play a vital part in the reproducible manufacturing of plane and spherical precision optics. Whereas with viscoplastical polishers (pitch) the decisive matching is achieved virtually automatically through the relative speed and pressure distribution in the mutual contact during the polishing process, an accurate preadjustment is absolutely essential if thermoplastic polishers are used for the replica polishing technique.
Fabrication of 32" F/3.8 Lightweight Mirror
Authors: Janeczko Donald J. , Chapman Rod
Published: February 2023

A lightweight mirror (gas-fusion bonding process) was fabricated. Blank fabrication, curve generation, grinding, polishing, tools, handling, coating and cleaning will be discussed.
Superpolishing Sapphire
Authors: Weis O. , Hader B.
Published: February 2023

We discuss superpolishing of a-cut sapphire which leads to a residual roughness less then 0.05 nm rms. There remains no damage layer. Polishing time is typically 15 to 30 minutes. The flatness is determined mainly by prepolishing. Curved surfaces can also be polished by this method. The lowest roughness is achieved, if removal rates are low, i.e. about 10 nm/min which corresponds to about half an atomic layer per second.
Current Developments in Surface Figure Metrology
Authors: Greivenkamp John E. , Palum Russell J.
Published: February 2023

This review paper will examine the current state of optical testing for surface figure metrology. We will look at recent trends in commercial instruments as well as new developments in the technology of optical testing. This discussion will include topics such as software versatility and processing speed, high-speed data collection, new processing algorithms, long-trace optical profilers, larger data arrays, interfaces between interferometers and design programs, and aspheric testing. We will include our most recent results from our work in sub-Nyquist interferometry for measuring aspheric surfaces. The talk will conclude with a brief discussion of the current and future challenges that are facing the optical testing community.