bluuebunny/crossref_metadata_2025 huggingface dataset:
Specialized Interferometric Testing Techniques
Authors: Horwitz Joann
Published: February 2023

With higher and higher demands put on the performance of optical systems today, there has been a trend toward using nonspherical surfaces in these systems. Optical metrology is given the responsibility for testing these surfaces. Fortunately, many of these surfaces can be tested in a straightforward manner. Most conic sections fall into this category. By using the geometric properties of these surfaces of revolution, it is possible to test them with conventional interferometers with little extra special equipment. The geometry for these surfaces determines the test configuration and what accessories are required to do the testing. The geometry and actual testing configuration will be covered in detail. It is also to the metrologists' advantage that even if a nonspherical surface is not a conic, the departure from the near conic is small and the asphere can be tested as a conic section. There are mathematical means for finding the near conic. When the departure is on the order of waves, the surface can be tested as the near conic and the results evaluated using standard automatic reduction techniques. With the advent of more sophisticated measuring techniques and data reduction systems, wavefront departures approaching 12 waves can be automatically evaluated. These new techniques also permit the automatic testing and evaluation of surfaces that are nominally a plane or sphere but are so badly aberrated that the interference pattern is complex. As with any optical testing, care must be taken to properly configure and align the test set up. With the proper attention paid to these points, a reasonably noncomplex fringe pattern nearly free of alignment errors can be obtained and evaluated.
Infrared Materials - Germanium
Authors: Adams J. H. , Thomas D. W.
Published: February 2023

A brief history of Germanium usage is reviewed and its properties of interest to the infrared community are discussed.
Cutting and Grinding Coolants
Authors: Vollaro Charles
Published: February 2023

Just as in convential maching and grinding, seldom is consideration given to the fluid to be used in conjunction with diamond tools.
Inspection of Diamond Tools
Authors: Baker Philip
Published: February 2023

This paper will discuss the existing techniques used to qualify precision single point diamond tools that are used to machine non - ferrous metals to microinch tolerances.
Single Point Diamond Turning Machine for the Small Optics Shop
Authors: Thompson Dan
Published: February 2023

Summary not available.
Shaping Methods and Cost Trade-Offs
Authors: Plummer John L.
Published: February 2023

Because of a worldwide sluggish economy many manufacturers of optical instruments are searching for ways to reduce cost of their products. This talk will attempt to deal with this subject by examining some potential tolerancing trade-offs which have proven successful in reducing manufacturing cost without adversely affecting optical performance.
The Modular Technique of High-Speed Precision Lens Fabrication
Authors: Munroe J. Clyde
Published: February 2023

Industry demands in this country are always towards more cost conscious and competitive production. Lens fabrication is no different.
Ask My (or Your) Calculator Anything
Authors: Palmer Eric M.
Published: February 2023

Over the past five years I have written several programs for hand-held programmable calculators. Most of these programs have dealt with specific technical questions in the fields of optical design and optical fabrication. I have collected these programs in a notebook which is divided into ten sections by catagory. Section names and the individual program titles within each section are given in Table I. No attempt has been made to cover the field of optics or any subtopic thereof. None of these programs were originally written with the idea of publication or sale. I display them as a group on this occasion as a modest example of what can be done to take advantage of the tremendous computational power that has been bequeathed to each of us by the inventors of the pocket calculator.
Statistical Techniques for Process Control
Authors: Wood Don
Published: February 2023

Manufacturing processes can often be analyzed as a sequence of independent operations where the quality of the finished product is some function of in process quality characteristics for each operation. Objectives in analyzing a process should be to determine the important variables, how they affect the process, the correct values to optimize the process, and the tolerances required for the process to remain in control. These objectives can be most effectively accomplished by the construction of quantitative process models. The initial cost is usually quickly amortized by lower unit cost and increased product quality.
Influence of the Substrate Surface on the Performance of Optical Coatings
Authors: Guenther Karl H.
Published: February 2023

In the production of optical elements, surface layers can be created on optical glass in various ways, particularly if we are dealing with sensitive glasses of low acid or alcali resistivity. Basically, any exposure of a glass surface to a wet or a humid environment can cause a surface layer, although different mechanisms may be determining its thickness and composition. In the production of optical elements, their surface can be endangered before coating by polishing, cleaning, general handling and even by storage. The first two cases will be discussed in general and illustrated by examples. It is shown that all of these surface layers - independent of how they originate - alter the optical properties of subsequently deposited thin film interference coatings, particularly of antireflection coatings, in a much disturbing manner.
Polarization and Phase Effects in Coatings
Authors: Scott Marion L.
Published: February 2023

Thin film interference coatings are a commonplace addition to surfaces polished in a modern optical fabrication facility. These coatings can have a dramatic effect on the optical performance of the optical component to which they are applied. In this presentation, I intend to concentrate on those effects which are related to polarization of the incident beam or the phase shift difference on reflection (retardation).
Aspheric Component Fabrication
Authors: Capiotis Gust
Published: February 2023

I would like to describe the fabrication, testing and coating techniques used at Pennsylvania Optical Company to produce an unusual Optical Component illustrated in Figure 1.

Glass types FD7 or SF7 are required for this component. These materials have moderate stain resistivity. Normal use of this glass type for conventional lens fabrication would probably be relatively trouble free; however, because of the many operations and handling during the coating operations considerable cosmetic problems are encountered. On-going diligence is required to keep quality at an acceptable level. Investigations reveal that pressure, polishing speed and polisher material selection will influence latent scratch control. Considerable studies have been made on this topic by major optical glass manufacturers.
Optical Surfacing Center Using Computer Controlled Machinery
Authors: Atkinson Leland G. , Moore Duncan T.
Published: February 2023

The optical fabrication process has been traditionally labor intensive. With the advent of computer controlled machinery in the past decade steps have been taken to automate the optical fabrication process in specific cases. High speed fabrication facilities exist in most large optics companies for production of spherical surfaces with a few rings of power and irregularity. These facilities still require a great deal of labor intensive set up to initially produce the desired surface and then subsequent monitoring of the surfaces to determine if the surfaces are within the tolerance band. The subject of this work is to determine to what extent it is feasible to automate the set up and quality control using computer controlled machinery. The types of parts which are being considered are spherical surfaces on glass workpieces with diameters of from one half to three inches. Almost any radius of curvature surface can be produced.
Computer Controlled Polishing and Testing of Glancing Incidence Mirrors
Authors: Wright Geraldine A. , Fleetwood Charles M. , Thomas Roger J.
Published: February 2023

Controlling the polishing and testing of glancing incidence mirrors with a computer allows them to be fabricated with a precision that is not practical to achieve by hand. At the Goddard Space Flight Center we are automating the fabrication of Wolter telescopes for use in the extreme ultraviolet.
Determination of Thickness and Composition of Multielement Coatings on Computer Disks Using Energy Dispersive X-Ray Fluorescence
Authors: Wheeler B. , Thomas C. , Gedcke D. , Welco A.
Published: February 2023

Manufacturing of multielement coated disks for the computer industry generally demands close tolerances of both the com position and the thickness of the plated or coated material on the substrate alloy. Since these types of materials are opaque to the visible spectrum, the most convenient and reliable method for these determinations fall into the non-destructive technique of x-ray fluorescence.
Infrared ION Implanted GaAs Optics
Authors: Mentzer M. A. , Hunsperger R. G. , Bartko J. , Zavada J. M. , Jenkinson H. A.
Published: February 2023

Free carrier compensation by ion implantation is an important fabrication technology for the formation of infrared optical waveguides for a variety of applications. Gallium arsenide is a very attractive substrate material for optical fabrication since it is transparent out to the far infrared. In addition, GaAs, together with its related ternary and quarternary compounds, has many of the optical and electronic properties necessary for integration of optical devices into sensing and signal processing circuits. This will afford the ultimate merger of the VLSI electronics and GaAs optoelectronics, as well as the monolithic integration of microwave electronic devices such as gunn diodes and Schottky gate FET's, with GaAs optical components. Experiments were performed to characterize the influence of various H+ implantation parameters on the carrier compensation process and to relate the resulting optical effects to electronic changes. The design techniques utilized are applicable from 1 to 12 micron operating wavelengths and may be utilized in a variety of specific device applications.
Bidirectional Distribution Surface Finishing
Authors: Stover John
Published: February 2023

Summary not available
The Effect of Surface Errors on Optical Performance
Authors: Elson J. M. , Bennett H. E.
Published: February 2023

Surface irregularities range in lateral dimensions from those usually associated with optical figure error through values associated with zonal errors to those usually described as microroughness and extending to submicron dimensions. Typically, the irregularities are a small fraction of a wavelength in height so that physical, not geometrical, optics must be used to calculate their contribution to optical performance. The total integrated scatter (TIS) from irregularities is given by the expression (4πδ/λ)2, where λ is the wavelength and δ is the rms roughness of the surface. TIS is defined as the total reflectance of the surface minus the specular reflectance, i.e., the fraction of the total reflected light that is scattered into a hemisphere. The amount of scattered light is proportional to the mean square of the heights of the surface irregularities. No upper limiting value of lateral dimensions of the surface irregularities appears in this scalar theory, although, for normal incidence, the scattering becomes virtual when the lateral dimension ℓ of the irregularities becomes less than λ. The more closely spaced the irregularities are, the larger is the angle into which light is scattered. When ℓ ≈ λ, as is true for zonal irregularities, the scattered light is very close to the specular direction (typically a few minutes of arc), and, for still larger lateral dimensions such as are associated with figure errors, its main effect is to decrease the on-axis intensity of the focused beam. It follows that if near-angle scattering is of primary importance, as for example in a system projecting a light beam, the most important surfacing parameters may be zonal and figure errors. Large-angle scattering may also be important but becomes of particular concern for an imaging system such as a telescope where light may enter the optical system from large off-axis angles, strike the optical component, and be scattered into the focal plane. When large-angle scattering is important, the height of the more closely spaced irregularities beomes critical. A calculation of the effect of microirregularities having a range of autocovariance lengths on the performance of a typical mirror telescope will be given to demonstrate the possible degradation effects of both near- and large-angle scattering. Vignetting effects that occur when the mirror is illuminated at off-axis angles are also considered. (It should be pointed out that we are discussing scattering of light into the optical path by the optical components themselves. No arrangement of baffles will have any effect on this type of scattered intensity. Programs such as APART or GUERAP are designed to prevent light scattered from the mounting system from reaching the focal plane, not light scattered directly into the focal plane by the components themselves.)
Non-Contact Precision Surface Measurements
Authors: Lange Steven R.
Published: February 2023

An instrument capable of making precision surface measurements, including RMS roughenss, autocovariance and power spectrum, in a non-contact mannner is described with measurements presented on super-polished optical glass and diamond turned samples.
Surface Evaluation Techniques for the Optics of the Future
Authors: Bennett Jean M.
Published: February 2023

A key to improving the performance of optics and optical systems is to reduce scattering and absorption losses in thin film coatings and in the underlying substrates. Scattering can be measured by collecting the light scattered into a hemisphere (total integrated scattering, or TIS) or as a function of angle. The scattering can be related via scalar or vector scattering theories to the root mean square roughness and other statistical properties of the samples. Surface roughness can be measured by a noncontact heterodyne interferometric technique or a diamond stylus profiling instrument. If the optics are too large to fit into the measuring instruments, replicas can be made of parts of the surface and analyzed using one of the above techniques. Subsurface damage produced by the polishing process can in some cases be determined by a light scattering technique. Absorption in substrates and coatings can be distinguished from absorption at air-film or film-substrate interfaces using adiabatic calorimetry. The techniques to be described can measure absorption in parts per thousand, scattered light in parts per million, and surface roughness down to nearly atomic dimensions. Examples of some of the higher performance optics made possible by the sensitive evaluation techniques will also be given.
The Specification of Optical Surface Quality Using the Finish-Function Relationship
Authors: Church E. L.
Published: February 2023

The quality of an optical surface depends on a number of factors, the most important of which is its surface topography. This paper is concerned with the problem of measuring and specifying the topographic finish of homogeneous, isotropic mirrors; an area of considerable practical interest.
Design and Construction of High Speed Optical Generators
Authors: Plummer John
Published: February 2023

This paper will discuss design parameters and construction of computer controlled diamond generating machines which have the capability of producing close tolerances of center thickness sphericity and sub-surface fractures. Slides of some recently developed machines will be shown.
Fabrication of Micro-Optics
Authors: Schubert Klaus
Published: February 2023

Micro-Optics has existed for quite some time. However, no one manufactures these on a production basis. This article will show some methods on how to make small lenses and prisms on a production basis fr the raw glass to the finished product.
Ultra-Precision Flat Polishing
Authors: Leistner A J
Published: February 2023

The technique of Teflon polishing developed at this laboratory for producing ultra-flat surfaces and some of the results achieved with it are described.
Design Parameters for Diamond Tools
Authors: Taurone Dom T.
Published: February 2023

A typical diamond wheel marking shows these variables: The six variables that make up a diamond wheel all have an affect on the grinding operation. Each must be carefully chosen in order to achieve the optimum (1) rate of stock removal, (2) surface finish, (3) edge chipping, (4) wheel life and (5) cost of grinding.
Sub-Nyquist Interferometry
Authors: Greivenkamp J. E.
Published: February 2023

The primary limitation of conventional phase-shifting or heterodyne interferometry (PSI) is its inability to measure the profile of surfaces or wavefronts with large departures from a best-fit reference sphere. The surface must have limited asphericity. The reason for this limitation is that the current phase-shifting algorithms will only correctly reconstruct the wavefront if the change of the wavefront between adjacent measurement points is less than a half wave. This requirement arises from the need to remove 2π phase discontinuities that result from the inverse tangent in the data reduction algorithm for PSI. These statements are equivalent to saying that the maximum permissible fringe frequency in the interferogram is the Nyquist frequency of the sensor (there must be two samples per fringe). Fringes at higher spatial frequencies are aliased by the sensor. Attempts by others to overcome this limitation, which restricts the degree of asphericity permitted on the measured surface, have included using detector arrays with more elements, longer wavelengths, computer-generated holograms and null lenses, or two-wavelength techniques.
Backprojection Reconstruction of Laser-Drilled Cooling Holes1
Authors: Tan H. L. , Viscito E. , Allebach J. P. , Delp E. J.
Published: February 2023

Automated laser drilling of cooling holes in jet engine parts is an important part of the aircraft engine manufacturing process. Proper hole placement and shape is critical to attaining required cooling function without sacrificing structural integrity. Due to variability in the laser drilling process, each hole must be inspected individually. A video camera coupled with a precision, computer-controlled manipulator such as that used to position the part for the drilling of each hole, offers the potential for an accurate, high speed inspection system.
A New Algorithm for Rapid Automatic Reduction of Test Interferograms
Authors: Angel J. R. P. , Wan Der Shen
Published: February 2023

The automatic reduction of single test interferograms is typically done by ridge following algorithms. The effect of this approach is to smooth high frequency structure in the surface, on a scale less than the fringe separation. We have developed a new algorithm that involves no smoothing and is very fast. The result for any individual interferogram contains errors of ± λ/20 in the wavefront, but when reductions of many interferograms with random piston errors in phase are combined, these errors average out. This method will be especially valuable for the metrology of very large telescope mirrors, when seeing in a large test tower is likely to give as large errors as the algorithm error, and vibration is likely to compromise phase shifting analysis methods. Preservation of high spatial frequency information is especially valuable for telescope mirrors, whose tolerance is of order 0.02 waves rms surface error on a scale of 5 cm.
In-Process Metrology, Handling, and Cleaning
Authors: Chen Gih-Horng
Published: February 2023

An overview will be presented to describe the practice of in-process metrology, handling, and cleaning in optical fabrication. Standard shop practice will be reviewed with emphasis on the recent process development in fabricating state-of-the-art optics.
Introduction
Authors: Brown N. J.
Published: February 2023

Summary not available.
Production Blocking Techniques
Authors: Johnson Kris W.
Published: February 2023

Production blocking of lenses and prisms is unfortunately an area that tends to have the back seat to how well you can generate a block, or the details of effective pellet lapping. Of course, all the processes take second fiddle to high speed polishing. Everyone recognizes, in theory, that production fabrication of precision lenses is not how well any one operation works, but the effective marriage of the entire process.
The Large Optical Generator: Status and Goals
Authors: Kuhn William P. , Ketelsen Dean , Parks Robert E. , Kittrell Cary
Published: February 2023

The Large Optical Generator (LOG) is a numerically controlled vertical milling machine. The LOG was designed for the generation of rotationally symmetric monoliths of upto 8-m in diameter or off-axis segments of surfaces upto 15-m in diameter. The LOG machine has an 8-m diameter capacity, 5-m horizontal travel and 1.5-m vertical travel and positioning to 1 micron on the horizontal and vertical axes.
A Simplified Analysis of Polishing Large Aspheric Surfaces
Authors: Angel J. R. P. , Cheng A. Y. S. , Brown D.
Published: February 2023

Astronomical telescopes of the future need large paraboloidal mirrors as fast as f/1. Machines for numerically-controlled generation of such aspheric surfaces are now available. However, polishing fast aspherics at close to diffraction limited performance remains a difficult problem. We have analyzed the capabilities and limitations of different polishing tools. These include small rigid laps, flexible and soft faced laps and actively stressed laps. We apply to each a criterion for successful fine grinding and figuring, namely that a lap should be able to accomodate to the surface to within a certain accuracy, about 0.3μm for figuring. This leads directly to stringent size limitations for rigid laps that are rotated or radially stroked. Laps that conform to changes in curvature by bending under the polishing pressure must be adequately flexible. Formulae for lap thickness to meet the above criterion are derived. The effect of small errors of lap fit are in general largely averaged out, except at the mirror edges where overhang droop always tends to produce the same error. Lap thickness to keep the systematic error low, say below λ/10, are derived as a function of the amount of overhang. Finally actively stressed laps are analyzed to determine the combined bending effects of moment actuators and polishing pressure. A lap with 24 computer-controlled edge moment actuators is now being built. It will offer very substantial advantages for steep aspherics, provided that the applied bending moments are controlled accurately enough, about 0.1% for an f/1 mirror soon to be polished. For secondary mirrors and Schmidt plates, a tool which bends under edge moments produced by levers and springs is proposed.
Microcomputer Controlled Polisher for Axisymmetric Aspherics
Authors: Small Donald W. , Hoskins Steven J.
Published: February 2023

Polished aspheric surfaces are used in many military and space applications to improve system performance while allowing reduced size, weight, and complexity. However, the high cost of manufacturing aspheric surfaces is a major obstacle to their more extensive use. Our goal in developing a microcomputer controlled polisher was to improve on traditional labor-intensive manufacturing techniques by automating the polishing process and improving its efficiency. We also wished to make the process easier for moderately skilled opticians to use on a routine basis. In this way we hoped to reduce the cost of fabricating axisymmetric aspheric surfaces.
A new bi-aspheric molded glass lens for single lens pick-up system
Authors: Tanaka Yasuhiro , Nagaoka Yoshitomi , Ueda Masaaki , Itoh Masashi
Published: February 2023

We have developed a bi-aspheric lens, intended for a compact disc (CD) player pick-up, which is manufactured by a high precision glass molding process and has been mass-produced. The lens realizes a single-lens system for a CD player pickup, that has function of both an objective lens and a collimator lens, while conventional system use 4 or 5 spherical lenses. The lens has a small size (5.0 mm diameter X 4.2 mm thickness) and has weight of only 300 mg. With the small lens we have also developed a very small size CD player pick-up, having a height of 13.3 mm, much shorter than 18.5 mm height of our former one. The off-axis wave-front aberration at an image height of 150 microns has been designed to be 0.035 wave rms. Such performance should be considered excellent, where a relative local shift between a laser diode and a lens is avoidable due to a tracking, a focusing and a set up error. The observed on-axis transmitted wave-front aberrations of the molded lenses are less than 0.03 wave rms.
Spin Casting a f/1.75, 3.5 Meter Honeycomb Blank of Borosilicate Glass
Authors: Goble L.
Published: February 2023

At Steward Observatory, we are developing a process which will create honeycomb telescope mirror blanks of borosilicate glass. These castings which weigh approximately 25 percent of the solid alternative and have deep, up to f/1, curvature in the front faceplate are formed by spinning molten glass in an open mold. We have undertaken a development program to make a giant 8-meter diameter telescope mirror with this process. Three mirrors at 1.8-meters have been cast using a prototype furnace.1 We are nearly ready to cast the first 3.5-meter mirror using this method. Two years of activity in preparation have built a new facility including much of the casting furnace for the large 8-meter mirrors, Figure 1. The turntable, bearing, rotation drive system, slip ring, and electrical power supply are sized and completed for 8-meter mirrors. The furnace, refractories and electrical heaters are a subset in which up to 5-meter mirrors can be cast. The furnace hearth will be expanded later to reach the circular 10-meter diameter walkway shown. The furnace lid shown hanging on the wall and the mirror castings are moved within the facility using a built-in 40-ton bridge crane. Systems testing of the furnace and assembly of the mold required to shape the mirror will continue during the summer and then casting of the 3.5 mirror in October.
"Loading" and Selectivity Flow Dependence of Plasma Assisted Etching/Deposition Processes*
Authors: Zarowin C. B. , Bollinger L. D.
Published: February 2023

The loading and selecting flow dependence predicted by a theory (1) of plasma assisted chemical vapor transport processes are confirmed experimentally. These are applicable to reactive ion or plasma etching and plasma assisted chemical vapor deposition. The central predictions confirmed by these results are: 1 - the selectivity flow dependence can approach infinite selectivity at certain "low" flows; 2 - the loading flow dependence is linearly increasing at "low" flow, in agreement with earlier loading behavior, but, in addition, is also exhibits a flow dependence which increases from zero at zero flow to a maximum and decreases to zero loading at infinite flow. This flow dependent selectivity and loading is shown to be a very sensitive test of the validity of the theory (1) predicting this behavior.
Measurement of Surface Contour using a Pencil Beam Interferometer
Authors: Swain D. M. , Brooks L. D.
Published: February 2023

A novel surface slope measuring interferometer, the heterodyne pencil beam interferometer (HPBI), has been designed, fabricated and is being tested. The HPBI was designed to measure a wide variety of optics including concave and convex aspheres as well as optics with non-circular shapes. The HPBI system presented is a scalcable design ultimately capable of measuring optical surfaces several meters in diameter. A detailed mechanical and optical analysis and tradeoff study was performed to ensure the high performance of the HPBI. An algorithm was developed to convert slope data to a surface profile contour map. Details of these features will be discussed. Sample output from typical measurements will be presented.
Mid-Frequency Roughness Measurements on Optical Surfaces
Authors: Bristow Thomas C. , Bouzid Ahmed , Bennett Jean M.
Published: February 2023

Microroughness for profile lengths of 1 mm or less can be measured with several very sensitive mechanical contact and optical noncontact instruments.1-5 These instruments are sensitive enough to measure roughnesses of less than 1 Å rms. Lateral resolutions vary from a few tenths of a micron for a mechanical contact type instrument1,2 to one or more microns for optical non-contact profilers.3-5 The best polished optical surfaces have microroughnesses of less than 10 Å rms, and values of 1 - 2 Å rms have been measured for specially polished samples of Zerodur, silicon carbide, and sapphire2. On the other hand, optical figure measurements are routinely made on samples ranging from diameters of a few centimeters to several meters. Flatness of a few hundredths of a wavelength of visible light can be achieved in the best cases. For example, an rms figure error of one hundredth of a wavelength at a wavelength of 5000 Å is 50 Å.
A Nodal-MTF Bench For Evaluation of Optical Systems
Authors: Fantone Stephen D.
Published: February 2023

Nodal benches1–4 have long been used to characterize optical system performance. The chief feature of a nodal bench is the nodal bearing which rotates the lens over its nodal point for off-axis evaluation. When this is done, there is no displacement of the image in the paraxial image plane. Any image displacement noted as the lens is rotated over its rear nodal point is a direct measurement of distortion. Parameters such as * Equivalent, Back, and Flange Focal Lengths, * Blur Spot Size, * Field Curvature, * Distortion, * Lateral Color, * Aerial Image Resolution, and * Spherical Aberration can be directly measured on a nodal bench. Visual examination of an image is many times the most effective way to judge optical quality and to diagnose lens defects.
Elastic Emission Machining and Finished Surface Properties
Authors: Mori Yuzo , Yamauchi Kazuto , Endo Katsuyoshi
Published: February 2023

In Elastic Emission Machining (EEM), ultra fine powder particles having diameters of much smaller than 1.0 micron are employed. They are transported to the work surface by utilizing the flow of fluid. When they contact with the work surface, atomic removals take place through the atomic interactions between these two surfaces. Mechanism of EEM is similar to the chemical etching, in other words, chemical activities of the solid surfaces are employed in EEM instead of etchant in chemical etching. So that not only in geometrical sense but also in crystallographical one, excellent properties can be expected. Finished surfaces are examined by some methods for example, photoluminescence method or scanning tunneling microscope. Obtained results firmly show the superiorities of the surfaces after EEM.
Computer Design and Fabrication of Optical Surfaces
Authors: Windebank Robert , Cooke Frank
Published: February 2023

Computer Design of Surfaces from Desired Image Output and Source Position and Size. The Programs Calculate the Surface Topography to Direct Input Rays to Required Output Positions. Rays are Presented on Screen and Calculated Data on Printer. When Design is Approved Program Directs Data to New Computer Controlled Milling Machine Using Diamond Tools. Different Programs Allow Computer To Figure Surface or Use Fixed Surface and Show Variable Image from Variable Source Position. Applications Include Rear View Mirrors and Headlights for Automobiles, Heads-up Displays and Streetlights. Surfaces Need Not BE Surfaces of Revolution or Any Conventional Surface. Fabrication Machine Has 5 Axes and Can Hold Cutting Tool at Normal to Surface at All Times. The Directly Connected Machine is Addressable to Around 4×10-6 Inches and Has a Cutting Volume of 10 x 10 x 5 Inches. A Large Range of Materials Can Be Utilized Including Those For Glass Replication and Molding i.e. Production Molds for Large Volume Low Cost Items . A More Advanced Machine Under Construction Will Have Work Space of 48 x 24 x 24 Inches and Metrology to Values of Better than 2 X 10-6 Inches in the X, Y and Z Axes. Surface is Around 35 A. RMS and Contour to 1 Wave at 6328 A.
Off-Axis Parabolas, Techniques for Small Shops
Authors: Hardin Larry C.
Published: February 2023

A metal off-axis parabola is fabricated using simple machine tools when CNC equipment planned for the job fails to perform.
ISO Organization and international Optical Standards
Authors: Walter Hermann
Published: February 2023

ISO, the International Organization for Standardization, was established in 1946. Today ISO has 90 members; those are the national standards institutions of the respective countries. The scope of ISO work comprises standardization in all technical fields with the exception of electric and electronic engineering, which is handled by the International Electrotechnical Commission (IEC). ISO's administrative center is the ISO Central Secretariat located in Geneva/Switzerland. The technical work of ISO is allocated to Technical Committees (TC's), each being assigned a particular technical field. Depending on the complexity of the technical field, a TC can divide its tasks and allocate the parts to Sub-Committees (SC's). A SC, in turn, can subdivide its tasks and allocate them to Working Groups (WG's), the WG being the smallest and most specialized unit in the ISO structure. Each of the TC's and SC's has a secretariat which is provided by one of the member organizations of ISO. At present, the technical structure of ISO consists of 164 Technical Committees, 644 Sub-Committees and 1551 Working Groups. The TC of prime interest for the optical community is probably TC 172 "Optics and Optical Instruments", comprising 9 SC's and 17 WG's. The work of TC 172 will be discussed in more detail.
The Metrology Crisis and the Optics Industry
Authors: McGee Walter J.
Published: February 2023

Recent presentations by the National Standards Educators Association have exposed the presence of a dimensional metrology crisis within our American industrial institutions that has not been recognized by management, the military customer, or the quality czars. This technical report focuses on those aspects affecting the design, manufacture, and qualification of optical system components. Although the crisis stems primarily from the lack of industrial acceptance and proper use of the national geometric dimensioning and tolerancing standard ANSI Y14.5M-1982, the failure of quality assurance departments to detect those errors gives implications that the crisis extends far beyond metrology itself. The revelation of the metrology crisis and its blistering impact on the multitudes of industries will be felt among those who cry for "QUALITY". This cry is being offset today with a new cry - "ACCOUNTABILITY". There can be no quality without accountability. Those who hold responsibility of confirming adherence to all design, manufacturing, and inspection requirements must be held accountable that they truly understand the content of those requirements.
Thermal Wave Imaging of Crystallographic Defects in Silicon
Authors: Smith W. Lee , Rosencwaig Allan , Willenborg D.
Published: February 2023

Thermal wave modulated optical reflectance is now the basis for a number of industrial optical inspection functions (1). We recently demonstrated that this method is capable of imaging crystallographic defects, such as dislocations and stacking faults, beneath the polished surface of silicon wafers (2). In this technique two lasers are employed in a pump-probe configuration. The pump beam, from an Ar+ laser, is acousto-optically modulated and focused to a 1-micron spot on the surface of the Si wafer. Absorption of these 2.5 eV photons perturbs the local electron-hole (or plasma) concentration and the temperature, both of which alter the optical reflectance (R) of the Si surface. A second, HeNe laser is employed to phase-synchronously probe the magnitude of the change in reflectance (ΔR), thus yielding the modulated optical reflectance (ΔR/R). Since subsurface damage or defects alter the plasma diffusion through recombination effects, the defects or damage can be detected with modulated optical reflectance measurements. We shall briefly review the metrology accomplishments of this new field of semiconductor optical inspection. We then describe modulated reflectance imaging of Si samples to illustrate detection of subsurface (a) stacking faults, (b) dislocations, (c) stress-induced slip, and (d) post-anneal implant damage.
Implementation of Sub-Nyquist Interferometry for Measuring Aspheric Wavefronts
Authors: Greivenkamp John E. , Palum Russell
Published: February 2023

Our efforts to modify a commercially available phase-shifting interferometer into a full sub-Nyquist interferometer capable of measuring highly aspheric wavefronts are discussed.
Unconventional Polishing
Authors: Jacobs Stephen D.
Published: February 2023

Obscure methods for optical polishing will be described, including magnetic field-assisted polishing, dry ice "snow" polishing, and high pressure etching/polishing.
The Single Point Diamond Turning (SPDT) Of Optical Surfaces For Visible Wavelength Applications
Authors: Gerchman Mark Craig
Published: February 2023

Recent advances in machine tools for single point diamond turning have significantly improved the quality of machined surfaces available. The most recent generation of SPDT machines are producing optical surfaces suitable for many visible wavelength applications. This presentation will examine the quality of current SPDT surfaces and compare them with reasonable criteria for visible wavelength surface specifications.
Methods of Cleaning Optical Surfaces
Authors: Hammer M.D.M.
Published: February 2023

A variety of methods for cleaning optical surfaces have been developed. substrate, coating, temperature, accessibility and circumstance all effect the selection of the optimum approach for cleaning of these optical components. A survey of several of the programs within the Hughes Aircraft Company, El Segundo Optical Engineering and Manufacturing facility, has turned up a broad range of cleaning techniques each individually tailored to the program specific requirements.
Improving the Accuracy of Retardance Measurements by a Compensation Technique Using HE-NE and ND:YAG CW Lasers
Authors: Bukhshtab Michael , Essex Douglas , Sacone Steven
Published: February 2023

Spectrophotometric, attenuation and compensation techniques were used for measurements of retardance in crystal quartz waveplates. The repeatability of compensation measurements is better than λ/2,000 for two wavelengths, 0.6328 and 1.0641 μm. This has been achieved by excluding multireflection images, precise orientation of all polarization components, fine adjustment and uniform irradiation of the optical elements of this dual wavelength, double channel measurement setup.
The Manufacturing and Testing of the W.M. Keck Observatory Primary Mirror Segments at Itek Optical Systems
Authors: Johnson Kris W. , Pitts Thomas G.
Published: February 2023

The manufacturing and testing of the segments for the W.M. Keck Observatory Primary Mirror is a coordinated effort in balancing production manufacturing with state of the art large mirror fabrication. The basic concept of production manufacturing is to reduce the manufacturing steps to their fundamentals by putting the quality into the machinery and fixturing allowing as little recurring manhour input as possible. The state of the art large mirror fabrication, on the other hand, usually involves the minimum in machinery and tooling as possible and using as much human skill input as necessary. The manufacturing and testing conducted at Itek is the result of the compromises that ensues when drawing that fine line between two very broad concepts.
The Keck Telescope Alignment Camera
Authors: Chanan Gary A.
Published: February 2023

We will present preliminary data from the Keck Telescope Alignment Camera, a wavefront sensor which provides information about the alignment, figure, and relative phasing of the thirty-six segments which make up the Keck primary mirror.
Spin-casting of a 6.5-m Honeycomb Sandwich Mirror for the MMT Conversion
Authors: Hill J. M. , Angel J. R. P.
Published: February 2023

1. Introduction The Steward Observatory Mirror Lab has recently completed the spin-casting of the largest structured mirror ever made, a 6.5-m f/1.25 honeycomb sandwich mirror of borosilicate glass. This mirror will be installed in the Multiple Mirror Telescope operated by the University of Arizona and the Smithsonian Institution, replacing the six 1.8-m mirrors that currently make up the MMT and thereby doubling its collecting area. The casting of this mirror represents the final step in development of technology to produce 8-meter-class lightweight mirror blanks. The honeycomb sandwich structure provides improved mechanical and thermal performance compared to solid blanks. The sandwich is ten times stiffer than the same mass of glass in a solid meniscus, leading to lower deformation under wind forces and lighter telescope structures. Ventilation of the honeycomb with air at ambient temperature reduces the mirror’s thermal time constant to less than an hour, allowing the mirror to accurately track the changing ambient temperature and reduce mirror seeing. Most of the large mirrors to be cast at the Mirror Lab will be extremely fast, in the range f/1.14 to f/1.25. For larger telescopes there is added incentive to keep focal lengths short, in order to minimize enclosure costs and wind-induced motion of the secondary mirror. The MMT Conversion has a particular need for short focal length: the new telescope must fit in the existing enclosure, designed for six 1.8-m f/2.7 mirrors, with only minor modifications.
Interferometric metrology for a 6.5-meter F/1.25 paraboloidal mirror
Authors: Burge James H.
Published: February 2023

Optical tests have been designed and analyzed for the interferometric testing of the highly aspheric 6.5-meter F/1.25 primary mirror which was recently cast at the University of Arizona to upgrade the Multiple Mirror Telescope (MMT.) An infrared interferometer using a CO2 laser, a null corrector, and a pyroelectric vidicon will test the surface during loose-abrasive grinding. Precision metrology for the testing of the polished surface will use a visible Shack-cube interferometer co-aligned with a BK7 null corrector, a HeNe laser source, imaging optics, and a CCD array. Both the infrared and visible systems have been carefully designed to give excellent performance in terms of wavefront correction, alignment sensitivity, imaging of the mirror to the detector, diffraction effects, ghost reflections, and ease of use.
Large Mirror Blank Fabrication
Authors: McGill Carol L. , Spangenberg-Jolley Julie
Published: February 2023

Corning has been selected to manufacture the mirror blank for the Subaru (JNLT) telescope. Corning will use proven materials and technology to produce this blank.
Polarization Effects in the AXAF Circularity/inner Diameter Station (CIDS)
Authors: Zweig D. A. , Convertito P. , Patterson J. S.
Published: February 2023

The effect of misalignment in the polarization control optics of the CIDS is examined. The analysis is used to evaluate current and improve future performance.
Component and System Metrology of a 10X Schwarzschild Camera for Soft X-Ray Projection Lithography
Authors: Himel Marc D. , Tichenor Daniel A. , Jewell Tanya E.
Published: February 2023

It has been shown that high-resolution imaging at soft x-ray wavelengths is possible.1 Experiments performed using a 20:1 reduction Schwarzschild camera show that 0.1 µm features can be fabricated using soft x-ray projection lithography (SXPL), but this system is impractical for lithography for several reasons including its small field of view (25 µm × 50 µm). This paper discusses our metrology efforts in testing both the individual mirrors and alignment of a 10× Schwarzschild camera that has a 0.4 mm diameter field of view.
An Update on Progress in Ion Beam Figuring
Authors: Wilson Scott R. , McNeil John R.
Published: February 2023

Results are presented from continuing research in Ion Beam Figuring (IBF). Theoretical aspects include a model of the ion beam figuring process for optics with a large amount of sag. Experimental aspects include results of aspherization of plane and f/1 spherical reflective optics. An update on the process characterization of various interesting materials (including silicon carbide) will also be presented.
Fabrication Challenges of Multi-focal-length Superachromatic Telescopes
Authors: Willey Ronald R.
Published: February 2023

There are many challenges associated with the design and construction of telescopes to have diffraction limited performance over the range from 400 to 900nm. The general applications of the system described are for television, film, and visual observation of objects from 300 meters to infinity with a 300mm aperture and focal lengths of 500, 1000, 2000, and 4000mm. The systems are designed to perform well at temperatures from -20 to 40 degrees Celsius and maintain high boresight stability when used as a tracking telescope. A sealed and purged instrument is essential for long term durability of the perforamnce. The figure shows the optical schematic of the system.
The Effects of Material Properties and Process Parameters on Surface Quality During Microgrinding of Glass
Authors: Lambropoulos John , Cumbo Michael J. , Jacobs Stephen D.
Published: February 2023

Recently, the Center for Optics Manufacturing at the University of Rochester has collected data on the deterministic microgrinding of glasses [Golini and Czajkowski, 1992; abbreviated as GC]. The system used is called OptiCAM and the glasses studied were SF7, F7, K7, BK7, SK7, and KzF6. The process parameters were the tool speed, the infeed rate, and the average diamond particle size. The measured parameters were the subsurface damage and the surface roughness. At the same time, the relevant material properties, the hardness and the fracture toughness, for the same glasses were measured by micro-indentation techniques [Cumbo, 1992].
Opticam PM Machine Design
Authors: Liedes Jyrki , Pneumo Rank
Published: February 2023

Rank Pneumo has worked with the Center for Optics Manufacturing and the Center's Manufacturing Advisory Board to design a multi-axis prism grinding machine. The Opticam PM is a three axis, high precision CNC reciprocating grinder. It is designed for the automated manufacturing of glass prisms. Unique features of the design incorporate electrolytic in-process dressing1 of the finishing wheel, a frictionless hydrostatic reciprocating cylinder, and machine resident metrology to provide RQM (Real-time Quality Management).
Features and Operation of the OPTICAM SMd
Authors: Bechtold Michael , Mandina Michael
Published: February 2023

The Opticam SMd (derivative) is a vertical spindle, multi-axis, computer numerically controlled (CNC) optics machining center. The SMd is a first generation derivative of the Opticam SM and its design complements and advances the industry modernization thrust at the Center for Optics Manufacturing.
Efficiency in Optical Testing of Large Optics
Authors: DeFranzo Carole L.
Published: February 2023

Itek Optical Systems is a leader in the production of large optics. This paper describes the process optimization used by Itek to generate a highly efficient and cost effective optical test system for high volume large optics.