bluuebunny/crossref_metadata_2025 huggingface dataset:
The Mechanics of the Machine-Tool-Workpiece System
Authors: Brown Norman J.
Published: February 2023

This paper is presented as a tutorial on lapping machine mechanics. Its purpose is to summarize what is known about conventional lapping machines with a minimum of mathematics. While this deprives it to some extent of the latitude and concise precision of formulae, it can reach a wider audience and treat several topics that can at present be formulated only with great difficulty.
Cleaning of Optics
Authors: Karow Hank H.
Published: February 2023

In order to develop an effective and reliable cleaning process for optics, one should follow series of logical steps. The usual practice of trial and error may lead to a useable process but it is frequently neither the most effective nor the most reliable solution.
Present State of Phase Measuring Interferometry
Authors: Horwitz Joann
Published: February 2023

This paper addresses the present state and trends in phase measuring interferometry from the user's point of view. Phase measuring interferometry extends the capabilities of interferometric testing. While phase interferometry has been used since the late sixties, it is only with the technical advances of the past few years that it has emerged as a practical tool for general use.
Lateral Shearing Interferometry of a Pulsed Laser Wavefront
Authors: White W. Travis
Published: February 2023

Using an adjustable air gap between two glass discs as a shearing plate, we have measured the aberrations of a frequency-tripled Nd:glass laser to within approximately λ/2 over the central 70% of the beam diameter. To estimate accuracy, we compared our method of lateral shearing interferometry to Twyman-Green interferometry, using a well-collimated He-Ne laser as a light source.
Problems of Fabrication of Fast Reflector Optics, for Instrument
Authors: Glecehill R. F. , Walter S. D.
Published: February 2023

Over sagging of plate glass to fabricate a low cost high curve folded reflector for a prototype obsidian dating instrument.
Large Optical Components for 10.6 μm Lasers
Authors: Sollid Jon E. , Reichelt Walter
Published: February 2023

This talk will discuss the Los Alamos experience in obtaining large components (up to 18 inches in diameter) for use in the four generations of carbon dioxide lasers built over the last ten years for inertial confinement fusion research. Topics of interest are single point diamond turning and large sodium chloride crystal production. The first of the four large laser systems was referred to simply as "67," since it was housed in Building 67. Next was a dual beam modular system called Gemini. The third was Helios and the last in the series was Antares, only recently completed (October ’83). Each system will be described and the lessons learned from each discussed. The primary contributions to the state of optical art probably came in two areas: single point diamond turning and large salt crystal production.
Review of Phase Shifting Interferometry
Authors: Wyant James C.
Published: February 2023

While phase shifting interferometry (PSI) techniques are not new, they date back at least to the 1950's1 and 1960's2, there is currently much interest in the use of PSI techniques for interferometric optical testing. This interest is at least partly due to the availability of both one-dimensional and two-dimensional solid state detector arrays and microprocessors.
Use of an Infrared Interferometer
Authors: Stahl H. P. , Koliopoulos Chris L.
Published: February 2023

The efficient manufacture of modern optical components requires a fast, accurate, easy to use and interpret testing procedure. To meet this need a prototype, next generation, infrared phase shifting interferometer, operating at 10.6 microns, was developed at the Optical Sciences Center for use during both the grinding and polishing stages of manufacture. This paper will present some of the applications for an infrared interferometer including uncoated optics both fine ground and polished, reflective optics, and aluminium tooling plate.
Optical Standards: A Discussion of the Work of the OSA Standards Committee
Authors: Silverstein Elliot M.
Published: February 2023

PURPOSE OF THIS PAPER: This paper is being presented to acquaint members of the optical community with the goals of the Standards Committee, and with current efforts of the committee toward achieving these goals. It is the intent of this and the accompanying papers to develop an interest among optical practitioners, designers, and manufacturers in the development and improvement of optical standards, and to encourage their active participation in the overall process of planning, writing, and commentary that will result in standards that meet the needs of the optical community.
Optical Drawing Standards
Authors: Parks R. E.
Published: February 2023

Efforts in the preparation of standards for optical components and instruments have been under way for several years at the international level. The International Standards Organization (ISO) has formed a Technical Committee on Optics and Optical Instruments (TC 172). The German Institute for Standardization, Deutsches Institut für Normung e.V., (DIN), acts as the host standards group or Secretariat for TC 172. The inaugural meeting of TC 172 was held in Pforzheim, West Germany in June, 1979. Within TC 172 there are nine subcommittees (SC) dealing with various aspects of optics as detailed in Table 1. Eleven nations participate actively in TC 172 while seven (France, W. Germany, Japan, The Netherlands, Switzerland, United Kingdom and the United States) are active in the work of SC 1, Fundamental Standards. The balance of this paper is concerned with the work of this subcommittee.
The Scratch Standard Is Not a Performance Standard
Authors: Young Matt
Published: February 2023

A British Prime Minister, Lord Palmerston, once remarked that only three people had ever understood a certain political situation: One was dead, the second was insane, and the third, Palmerston himself, had forgotten. The more I study the scratch and dig standards, the closer this remark hits home. I worry, however, that since I have not forgotten, I may be mad.
A Method for the Evaluation of Subsurface Damage
Authors: Anderson David S. , Frogner Michael E.
Published: February 2023

When a glass surface is abraded there is produced a surface damage layer consisting of two somewhat independent components: a relatively rough and pitted surface structure and an underlying system of fractures. To reveal the subsurface system of fractures acid etching has been used to open up the fractures for measurement.1,2 This method, however, is unreliable to varying degrees due to non-uniform etching rates at the top and bottom of the fracture. Moreover, most information on the structure of the fractures themselves is lost in the process. We have developed a method which also uses acid etching but uses specially prepared substrates that reveal very clearly the structure and depth of the fractures. Figure 1 depicts how the substrates are prepared.
Monitoring Aspherization with a Spherometer
Authors: Parks R. E. , Lam S. S. , Crawford R. C.
Published: February 2023

During the aspherization of a 1.8 m diameter, f/2.7 paraboloidal mirror, we used a bar type, two ball spherometer to quantitatively monitor the surface figure both in the ground and polished states. Parallel tests with a knife edge showed that we could have used the spherometer right up to the point the mirror was ready for final figuring against a null lens. We discuss the spherometer design, its use and the reduction of the sag data.
Specifying Fused Silica for Large Optics
Authors: Helm John B. , Miska Herbert A.
Published: February 2023

While there are currently four suppliers of Fused Silica to the U.S. market, this paper deals with material produced by the Corning Glass Works because that is what the authors are familiar with. Fused Silica is a synthetic, amorphous glass manufactured by a flame hydrolysis process. It differs from more conventional optical glasses in that it consists of nearly 100% pure silicon dioxide and therefore features exceptional transmittance in the ultraviolet as well as a very low coefficient of thermal expansion. While conventional optical glasses are manufactured by melting batches of the correct mineral constituents, fused silica is made by a chemical process in which silicon tetrachloride, natural gas and oxygen are combined in a burner and droplets of pure SiO2 are caused to precipitate.
Polishing Optical Parts with a Diamond Pad
Authors: Qiming Xin , Parks Robert E.
Published: February 2023

We did experiments recently to try to develop a method of polishing optical parts with a diamond pad.
Surface Profiling With Optical and Mechanical Instruments
Authors: Bennett Jean M. , Bristow Thomas C. , Arackellian Kevork , Wyant James C.
Published: February 2023

Two types of interferometers and a mechanical stylus-type instrument have been used to make surface profile measurements on the same samples. All had comparable height sensitivities, of the order of 1 Å rms, but different lateral resolutions. The Optel profilometer1 is based on the principle of the Nomarski differential interference contrast microscope in which two beams of light separated by 0.3 μm are measured by two detectors. Values of the surface slope are calculated from the detector signals; integration yields a surface profile. The Wyko heterodyne profilometer2 is based on the Mireau interferometer. One light beam is reflected from the sample while a second beam is diverted by a beam splitter to a reference mirror located between the microscope objective lens and the sample. A 1024 element linear diode array measures the phase of the interference fringe pattern which is then transformed into a surface profile. In the Talystep instrument3 a 1 μm radius diamond stylus contacts the surface with a 1-2 mg loading that is light enough not to damage the surface. The vertical motion of the stylus as it moves across the surface is converted into a digitized electrical signal that directly gives the surface profile. Results of measurements made on different types of surfaces using the three instruments will be compared to show repeatability, height sensitivity, and lateral resolution. Special features of each instrument will also be discussed.
Multi-step Universal Optical Component Tray
Authors: Hartmann Rudolf
Published: February 2023

Optical components such as lens elements require progressively better protection during their processing to prevent chipping, rubbing, or other damage. Shallow trays with foam or paper lining and cardboard separators are commonly used, but as optical surfaces are polished and coated, the parts become very delicate and can easily be damaged as they slide, particularly on their convex surfaces, on flat tray bottoms. Polished and/or coated optical components are often individually wrapped in tissue paper and/or sealed in bags for protection between final process/inspection steps, but wrapping, unwrapping, re-wrapping, etc. are very time-consuming and costly, and the parts can be easily dropped and damaged.
Current Performance of X-Ray Mirrors for Astronomy
Authors: Van Speybroeck Leon P.
Published: February 2023

Summary not available.
Fabrication and Testing of the Primary Mirror for the William Herschel Telescope
Authors: Brown D. S.
Published: February 2023

The primary mirror for the W.H.T. has an aperture of 4.2 metres, and a focal ratio of f/2.5. The mirror blank is of glass ceramic (CER-VIT) with an edge thickness of 0.55 metre. While the mirror focal ratio and thickness are fairly conservative, the performance specification for the mirror is novel. The form of specification used is now generally accepted as providing a useful means of describing the performance of ground based telescopes, but as yet there is no operational experience with a large mirror made to a specification of this form. Before work started on the mirror it seemed probable that some changes in both working and testing methods would be needed if the quality requirements of the specification were to be achieved and demonstrated. This paper deals mainly with those aspects of fabrication and testing which were most affected by the form of specification.
Neutral Ion Beam Figuring Of Large Optical Surfaces
Authors: Wilson S. R. , McNeil J. R.
Published: February 2023

In the quest for high speed optical fabrication techniques, ion beam sputtering has emerged as a viable means of removing material from an optical surface. Ion beam sputtering was first used as an optical figuring technique in the mid 1960’s[1,2]. Since that time, a number of investigators have applied ion beam sputtering as a figuring technique, with some degree of success.
Control of Plasma Etch Rates, Selectivity and Anisotropy with Plasma Parameters
Authors: Bollinger L. D. , Zarowin C. B.
Published: February 2023

We discuss the experimental verification of relations derived earlier
(1) between observable plasma etch rate, selectivity and anisotropy
and reactor parameters for a variety of etch gases. Since the
hetergeneous etch reaction is a superposition of neutral and ionic
components, it can be shown that such etch chemistry exhibits
enhancement and is made anisotropic by the energy transport of ions to
the etch surface only when the process is ion dominated. The ion
energy transport is controlled by the plasma sheath electric
field-electrode area/gas pressure-collision cross section ratio,
E.A./pQ, similarly controlling chemical anisotropy for ion dominated
etch reactions. Under such circumstances, we show that many etch gases
can yield identical ion transport, etch rate and anisotropy for a
given rf current, gas pressure, ion-neutral collision cross section
& electrode area, Irf/pQA.
Sub-Nyquist Interferometry -- Review and Status
Authors: Greivenkamp J. E.
Published: February 2023

Sub-Nyquist interferometry (SNI) is a new method of data analysis for phase-shifting interferometry (PSI) that greatly extends the measurement range of an interferometer for a given amount of data.1 This paper reviews the concept and principles of SNI, and details the progress towards a practical implementation of the technique.
The Use of High Resolution Phase-Measuring Interferometry in the Figuring of Large Symmetric and Asymmetric Aspheres
Authors: Anderson David S.
Published: February 2023

In-situ testing of large optics greatly increases the speed and accuracy of the figuring process. Rapid test data turnaround and precise contour map displays allow an optician using traditional polishing techniqes to progress rapidly to final figure. At the Optical Sciences Center we have developed a high resolution phase-measuring interferometer that we used during the final figuring stages of a 20-in. diameter, 97-in. focal length off-axis parabola and a 72-in. diameter, f/2.7 symmetric lightweight parabola. Both mirrors were tested and figured in-situ, the off-axis mirror on the table of the swing-arm generator and the 72-in. mirror in a test tower in which the mirror was supported on a rotary table equipped with a polishing arm. High resolution phase maps of each surface were obtained with resolutions of approximately 9mm/pixel and 2mm/pixel on the 72- and 20-in. mirrors, respectively. The phase contour maps were displayed on a video monitor and photographed with a 35mm camera on Tri-X film. The negatives were mounted directly as slides into circular slide mounts and displayed with a slide projector directly onto the slurry coated mirror. The optician then worked the high zones and patches using traditional polishing methods. The circular slide mounts allowed for easy alignment of the contour maps with the fiducialized mirrors. Test turnaround time from one polishing run to the next was about 2 hours allowing for rapid convergence to the final figure.
Alignment of a Mach-Zehnder Interferometer by analysis of fringe patterns produced by zonal plates
Authors: Moreno V. , Gómez-Reino C. , Garcia J.H. , Pérez M.V.
Published: February 2023

Recently a quick an easy method for optical alignment of the Mach-Zehnder interferometer (MZI) by an equilateral hyperbolic zonal plate (EHZP) has been proposed (1). When an EHZP is placed in front of the MZI, the light emerging from the interferometer produces only one focal cross on a field of view uniformly illuminated if the interferometer is adjusted and the principal focal distance of the EHZP is higher than the length of the MZI arms. However, when the interferometer is not adjusted, two focal crosses, defocalization of crosses and wedge fringes, may appear on the observation plane. These quantitative information, indicate, axial positioning error (transversal shift), length difference between arms (longitudinal shift), and arms axes mutually inclined (angular shift), respectively. A more refined adjustment may be achieve, if the observation is maked in a plane different to EHZP focal plane. In this case the hyperbolic family curves that can observe in the former plane (or elliptical, if we observe in the rear focal plane), overlap making moiré patterns, whose frecuencies and slope are in direct relationship with the relative adjust of the interferometer arms.
Quantitative Three-beam Ronchi Test
Authors: Lin J.A. , Hsu Jeremy , Shiue S.G.
Published: February 2023

Although Ronchi test is a simple and widely used test.it has long been recognized as a qualitative rather than a quantitative one. In the previous papers1,2, we showed the electron Ronchigrams and computer simulated interferograms to confirm the possibility to use Ronchi test to obtain the aberrations quantitatively. Optical components were tested recently. We first make some sinusoidal gratings by spatial filtering method. The gratings only have three diffracted spot in their Fourier spectrum, two weak first order spots and one strong zero order spot. Those gratings were then used in Ronchi set up to test lenses and mirrors. It seems quite easy to determine the coefficient of spherical aberration accurately from the ellipses of the three-beam interferograms. With the calculated value of spherical aberration,we could also determine other primary aberrations,such as coma and astigmatism.
Direct Phase Sensing Interferometry
Authors: Damron Steven W.
Published: February 2023

Many new optical test systems require the reduction of moderately aspheric fringe information. Often it is very difficult to evaluate these interferograms using fringe intersection data. In addition, testing environments such as vacuum chambers or large optical test configurations frequently can not be isolated from vibration.
Germanium-Cordierite Ceramics for Precision Mirrors
Authors: Mehrotra Yogesh
Published: February 2023

Germanium-cordierites are derived from the Mg-cordierite ceramic by partially replacing silica in the hexagonal structure with germania. A family of fully crystalline ceramics is thus obtained whose stoichiometry is given as: 2MgO • 2Al2O3 • (5-X) SiO2 • (X)GeO2. This ionic substitution lowers the coefficient of thermal expansion (CTE) of the material to zero or a near-zero value over a selected temperature range and also eliminates the associated anisotropy. Moreover, this temperature range for zero CTE can be "tailored" to suit the desired applications, a key advantage of Ge-cordierites.
Twyman Effect for Ule
Authors: Rupp Wiktor
Published: February 2023

F. Twyman was the first to observe a stressed layer of glass directly under the ground surface (1905). He also observed that the stress would disappear if the ground layer of glass is polished out. It was A.J. Dalladay (1921) who performed first quantative evaluation of this effect on plate glass.
Low-Scatter Large Beryllium Mirror Development
Authors: Moreen Harry A. , Adachi Peter
Published: February 2023

The development of a technique for fabricating large bare beryllium mirrors with low-scatter surfaces is described. The technique is based upon the application of a thick, high purity beryllium coating to a beryllium substrate. The technique has been identified as Be-on-Be Processing. The coating is fully dense, very low in dissolved impurities and free from both inclusions and second phase particles. These special qualities of the coating result in enhanced fabrication characteristics which result in the ability to polish a low-scatter finish superior to that which is obtained from conventional material. The character of the coating also results in enhanced response to rapid fabrication techniques. Single-point turning of the coating has been promising and numerous mirrors have been fabricated incorporating this technique. A Draper type polishing machine has also been modified to incorporate in-situ testing of figure utilizing interferometric evaluation of the Be-on-Be mirrors. Examples of mirrors produced with this technology are presented.
An Alternative to Pitch Blocking
Authors: Wiederhold Robert A.
Published: February 2023

Traditionally, for either conventional or high-speed processes, pitch is used to "block" or fasten a lens onto a holding fixture for optical polishing. Both blocking the lens for polishing and unblocking the lens for testing or further processing, is a time consuming and messy operation. A new, more efficient blocking technique has been devised which holds the lens in a plastic retaining ring, supported by a molded urethane lens seat. The adhesion between the lens surface and the urethane seat is sufficient to hold the lens stationary during polishing. Since no heat or lens cleaning is required for this process, a lens can be blocked and unblocked in seconds, reducing costs and simplifying testing. Details and applications for the process will be discussed in this paper.
Optician Training Concepts
Authors: Janeczko Don , Chapman Rod
Published: February 2023

A 15 minute videotape summary of the "Optical Craftmanship" optician training films (16) will be followed by a discussion of the characteristics of an optician training program.
ISO Environmental Test Standards for Optical Instruments
Authors: Parks Robert E.
Published: February 2023

International standards writing efforts in optics having been going on for the past 9 years under the auspices of the Geneva based International Standards Organization (ISO). This work is being done by Technical Committee (TC) 172 - Optics and Optical Instruments. Within this TC, Subcommittee (SC) 1 - Fundamental Standards has three Working Groups (WG). WG 3 - Environmental Test Methods, has prepared 18 draft environmental test standards and an introductory section defining the application of these tests to various classes of optical instruments.
State of the Art Review of Replicated Optics
Authors: Riedl Max J.
Published: February 2023

Reflective as well as refractive optical elements produced by the epoxy replication process have been in use for many years. The basic transfer process of a precise optical surface from a master onto a substrate is widely known and understood. However, to take full advantage of what the technology has to offer, one must be familiar with the application boundaries. These boundaries in the technical sense are set not only by the laws of physics, but even more so by the lack of available ideal materials. The task is therefore to do the best of what is available and continue to search for better materials and methods. Progress has been made over the years in this direction and to report on this progress is the purpose of this paper. Included in the presentation are some fundamental rules which must be observed when applying optical replication as the chosen manufacturing method. The intent is to guide the design engineer in his layout approach and to avoid possible disappointing surprises. Some thought about the future of replication will be given.
Power Spectrum Standard for Surface Roughness
Authors: Janeczko Donald J.
Published: February 2023

The typical lens or mirror requirement to control surface roughness is Rq (Geometric Average Roughness, Root-Mean-Square Roughness, RMS Roughness, etc.). It has been reviewed and found to have several serious flaws. These flaws result from the concept that requirements placed on an optical element should not be arbitrary but be based on form, fit or function and be complete.
Direct measurement of strain by moire deflectometry
Authors: Keren Eliezer , Kreske Kathi M. , Kafri Oded
Published: February 2023

Moire interferometry(1) is a technique for measuring the in-plane displacement of an object under stress. Two coherent beams are incident on the specimen at angles corresponding to the +1 and -1 diffraction orders of the grating etched onto the specimen. One diffraction order of each beam is reflected perpendicular to the surface, and these beams interfere to produce a fringe pattern. Local changes in the spatial frequency of the grating due to strain induce deflections of the two beams in opposite directions. As a result the fringe pattern describes contours of constant displacement in the direction perpendicular to the stripes of the grating. Mapping of strain components requires the differentiation of the displacement field by numerical or optical means(2).
Subsurface Damage in Optical Materials: Origin, Measurement and Removal
Authors: Hed P. Paul , Edwards David F. , Davis Janet B.
Published: February 2023

The detection, measurement and removal of subsurface damage is a major effort of the LLNL Optical Sciences and Engineering Group. We will describe and show examples of three methods we are currently using to detect and measure the depth of damage in glasses and crystalline materials: taper polishing and etching, constancy of chemical etch rate, and small specimen fracture. In addition, results will be given to show that the depth of damage can often be approximated from the surface roughness and Young's modulus.
Permanent Suspensions in Optical Lapping and Polishing
Authors: Yancey Paul J.
Published: February 2023

In optical fabrication shops many times the polishing and lapping slurries are thrown together without much thought or concern about the complex system that exists in that slurry. Many times the way the slurry is prepared can make the difference between mediocrity and perfection in the finished parts.
Chemo-Mechanical Polishing of Phosphate Glass as a Pretreatment to Rapid Final Polishing
Authors: Lindquist A. , Jacobs S. D. , Plotsker V.
Published: February 2023

It is well known that the use of one or more chemical etching steps during the fabrication cycle of glass-like materials reduces the subsurface damage introduced by loose and bound abrasive grinding. The etchant removes the outermost layer which consists of subsurface cracks and residual elastic strain. We are interested in applying this technique to a commercial phosphate laser glass as a means of increasing its thermal fracture resistance and reducing the time required for final polishing.
Float Polished Quartz Substrates*
Authors: Soares S. , Jungling K. , Stowell K.
Published: February 2023

Float Polishing is a unique polishing technique developed in Japan, that produces supersmooth damage-free surfaces for electronic, optical and magnetic applications. Crystalline materials such as quartz, silicon and sapphire, polycrystalline materials such as ferrite and zinc sulfide, and amorphous materials such as fused silica and zerodur have been polished using this technique. Float polished substrates have a typical surface roughness of approximately 2 Å, with a flatness of λ/20. Float polishing is used commercially in the fabrication of ferrite recording heads, sapphire crowns for watches and quartz resonators.
Diamond Turning of Optical Crystals
Authors: Saito T. T. , Syn C. K. , Fuchs B. A. , Velsko S. P.
Published: February 2023

Diamond turning (DT) has proven to be a cost effective optical fabrication technique for both aspherical and spherical/flat figures when precise geometrical tolerances are important(1). Diamond turning accuracy and capabilities have been steadily advancing. Our Large Optics Diamond Turning Machine (LODTM) offers state-of-the-art capability for sizes up to 1.6 m diameter. Large optics have been turned to better than 300 Å rms figure accuracy and small non-rotationally symmetric optics have been made to λ /10 in the visible(2). Our Precision Engineering Research Lathe (PERL II) has achieved a surface finish of 7 Å rms on electroless Ni(3).
Diamond Turned Electro-Deposited Nickel Alloys
Authors: Evans Chris J. , Polvani Robert S. , Mayer Anton
Published: February 2023

Many opto-mechanical components need abrasion and/or corrosion resistant surfaces. For some applications single point diamond turning is the preferred fabrication technique; however, wear of the diamond precludes use of some materials of choice.
Achieving a Low Stress Optical Finish on a High Aspect Ratio Beryllium Mirror
Authors: Hizny John J.
Published: February 2023

As optical systems become more complex, the designer is often forced to utilize exotic state-of-the-art materials to help solve difficult engineering problems. Often, as in the example presented here, the result is a design with inherent manufacturing problems. The component is a light weight beryllium mirror used in a Forward Looking InfraRed (FLIR) system. (Figure 1). The thin section design and the use of beryllium as the substrate material caused manufacturing problems.
Haidinger Fringe Monitoring of Very High Accuracy Prisms.
Authors: Lunt David
Published: February 2023

The fabrication of very high accuracy paired prisms is described using Haidinger fringe parallelism monitoring of the angles with a Shack interferometer.
Extending the caustic test to general aspheric surfaces
Authors: Hatch Marcus R. , Stoltzmann David E.
Published: February 2023

The caustic test is longstanding in the literature as a very powerful method for determining the surface figure of aspheric concave mirrors. Gaviola1 first described the test in detail. Until recently, the test had been applied typically to paraboloidal mirrors, although Cornejo-Rodriguez and Malacara2 have extended the test to measure conic surfaces. In this paper we present the relationships for caustic testing on general aspheres, as well as giving guidelines for the correct use of the test in actual testing setups.
10.6 Micron Wavelength BRDF Measurement on Low Reflectance A1 Samples
Authors: Reilly James P. , Kaczor Lorraine E. , Leonard Thomas A.
Published: February 2023

BRDF measurements made using a 10.6 wavelength laser on low reflectance, diffuse Al samples, showed the BRDF was spatially uniform and smoothly varying with scatter angle.
Goober and Kaboodle
Authors: Krajewski Charlie
Published: February 2023

A technique is discussed that allows a surface metrology system to perform data analysis on surfaces that are scratched, pitted, or even discontiguous.
Fabrication and Testing of Monolithic Lenslet Module (MLM) Arrays
Authors: D'Amato D. , Barletta S. , Cone P. , Hizny J. , Martinsen R. , Schmutz L.
Published: February 2023

Monolithic Lenslet Modules (MLM's) were originally developed at Adaptive Optics Associates, Inc., more than ten years ago for use in Hartmann wavefront sensor systems. They were used to form focal spots on a two-dimensional detector array. Image processing techniques were employed to locate the centroids of the spots providing the local slope measurement of the input wavefront.1 Advantages offered by MLM's include fill factors in excess of 99% and off-axis diffraction-limited performance.
An Automated Hartmann Test Using Rotating Diffraction Gratings
Authors: Blough C. Gary , Bowen John P. , Crawford Mary Kate , Haun Niels , Loewen Erwin G. , Malacara Daniel , Moore Duncan T. , Saxer Christopher E. , Wang David Y. H.
Published: February 2023

A system is designed and constructed for performing an automated Hartmann test with much greater speed and flexibility than the classical configuration. A rotating grating scanner eliminates the need for the screen, allowing mirrors with different f-numbers to be tested in the same setup. Measurements from the system compare favorably with data obtained by interferometric tests.
Results of Ion Figuring W.M. Keck Telescope Primary Mirror Segments
Authors: Allen Lynn N.
Published: February 2023

Since mid-1990 several W.M. Keck 10 meter Telescope primary mirror segments have been final figured using the ion beam figuring process. This optical fabrication technique uses a neutral ion beam to remove residual surface figure errors after the polishing process has been completed. The initial surface figure errors for the primary mirror segments have ranged from 0.090 to 0.350 µm rms; after a single ion figuring process correction cycle the errors have been reduced to 0.025 to 0.090 µm rms. The process and approach used, along with recent processing results will be discussed.
Surfacing and Testing of the E.S.O. 8.2m VLT Mirrors
Authors: Espiard Jean
Published: February 2023

REOSC has been awarded by ESO with a contract on July 25, 1989 for the polishing of the four VLT mirrors and the following tasks: - design and manufacture of the mirror handling tool and container, - transportation of each VLT mirror blank from SCHOTT's plant in Mainz (Germany) to REOSC's plant, - design, manufacture and assembly on the mirror of special devices for the mirror fixation in the cell, - grinding, polishing and testing of the four VLT mirrors.
Optics MODIL - Industrial Partnerships and University Interactions
Authors: Martin William R.
Published: February 2023

MODIL, an acronym for Manufacturing Operations Development, & Integration Laboratory is a methodology being pursued to mitigate risks and reduce costs of SDIO systems using industry, federal labs, and universities to solve producibility issues that are in many cases common to multiple systems.
Photon Tunneling Microscopy of Diamond Turned Surfaces
Authors: Guerra John M.
Published: February 2023

The process of precision machining an optical surface with a diamond tool can produce a fascinating topography that contains a wealth of information not only about the optical quality of the part, but about the tool, machine, and process as well. The topography is thus an archeological record of the machining characteristics at any point in time. In order to pull all possible information from the topography, one would like a profiler that is not only quantitative, with high resolution, but fully qualitative as well with a field of view large enough to teach topographic trends and facilitate pattern recognition.
Lens Blocking Method for Opticam
Authors: Novak Robert , Marro Marlene , Tipps Joe D. , Czajkowski Walter , DeMarco JoAnn , Salamon Peter A. , Matchett David , Caputo Fred , LeBlanc Glenn
Published: February 2023

A uv-curing 'cold' blocking adhesive has been developed by Loctite Corporation for use with the Opticam SM. The adhesive is a significant advance in the lens blocking process, as it eliminates heat-induced blocking strain; the most significant problem encountered with current hot pitch blocking methods. The new cold blocking adhesive is complemented by a new Kennametal lens blocking adapter tool and chucking system. The tooling offers substantially improved lens adapter to machine alignment and transfer, at considerably lower cost. The lenses are deblocked in a heated water and detergent solution, eliminating the environmental concerns of the current method.
"Process Science of Infrared Materials"
Authors: Cerqua-Richardson K. , Platt George , Vakiner John
Published: February 2023

A fundamental evaluation of issues affecting the fabrication of infrared-transmitting materials has been initiated as part of the Center for Optics Manufacturing's (COM) Process Science effort. The study, which will investigate the effect of process conditions on resulting material properties and optical quality, is aimed at improving the database of manufacturing related parameters which will lead to increased fabrication efficiency. The objectives and goals of the program will be reviewed.
The Future of Optics: Current Status of the Opticam SM
Authors: Borrelli John A.
Published: February 2023

The progress of the state of the art Opticam SM (a horizontal spindle, four axis CNC machining center) since its delivery to the Center for Optics Manufacturing in May 1992, has been remarkable. The Opticam SM is producing spherical glass microground surfaces with 100-200 Angstrom finishes and better than 0.5 wave p-v surface figure. The current status on the operation of this high precision machine along with surface results and future developments will be presented.
Limitations of Spatial Phase-Measurement Techniques
Authors: Creath Katherine , Schmit Joanna
Published: February 2023

Spatial phase-measurement (SPM) interferometry techniques are affected by a number of limitations. These include the wrong carrier frequency and detector nonlinearities in N-point spatial techniques, and leakage in the Fourier-transform method. Computer simulations in one dimension with straight, equally-spaced fringes reveal the character and magnitude of these errors.
Alignment of the Second Generation Wide Field/Planetary Camera: Optical Metrology of a Highly Aberrated System
Authors: Korechoff R. P. , Macenka S. A. , McGuire J. P. , Oseas J. M.
Published: February 2023

The Wide Field/Planetary Camera (WF/PC), built by the Jet Propulsion Laboratory (JPL), is one of five science instruments currently operating on the Hubble Space Telescope (HST). As has been well known since shortly after the launch of HST on April 24, 1990, the telescope's optical system (known as the Optical Telescope Assembly - OTA) contains a large amount of spherical aberration. In the year following the launch of HST, much effort went into determining the cause and magnitude of the spherical aberration [1, 2, 3]. In parallel with these HST activities, the fabrication of the second generation WF/PC instrument was proceeding at JPL. At that time the obvious question to ask was how could the optical design of WF/PC-2 be modified to correct for the OTA spherical aberration.
Assessment of Frictional Forces in Optical Polishing Using Atomic Force Microscopy
Authors: Cumbo M. J. , Lindquist A. , Jacobs S. D.
Published: February 2023

A large number of interactive chemical and mechanical factors significantly influence optical polishing processes. Motivated by Tesar's qualitative observations on the importance of friction in pitch polishing of fused silica [1], we have studied the influence of process chemistry on frictional forces in a more quantitative way, independent of any confounding effects introduced by a given polishing tool. The goal was to develop a microscopic laboratory technique for rapid screening of many different combinations of polishing process factors, thereby minimizing the number of experiments necessary to optimize glass removal rates on large-scale planar polishing equipment.
Bound Abrasive Polisher Concepts for the Center for Optics Manufacturing CNC Machining Centers
Authors: Lindquist A. , Puchebner B. , Cumbo M. J. , Rich T. , Jacobs S. D.
Published: February 2023

A major impediment to deterministic finishing of optical components is uneven polishing tool wear, which results in surface figure errors. In conventional viscoelastic pitch polishing with aqueous slurries containing CeO2, tools are pressed out periodically against a master reference as they become distorted. Surface quality (figure and finish) is achieved in a lengthy, iterative, labor intensive process. Natural felt pads and synthetic pads made from polyurethane have been employed to reduce polishing time, but the figure and smoothness achieved are inferior to those of pitch polished parts.
The Lens Designers' Challenge: The Manufacturable Lens
Authors: Welham Brian
Published: February 2023

Recent international events have resulted in a significant reduction in the U.S. Governments' spending on military products. There are many companies that have devoted most of their resources to developing and manufacturing these products and, as a result, are left with an excess of engineering and manufacturing capacity. Because of the availability of these resources, many companies are attempting to compete in the consumer optics market. Most products for the U.S. consumer market are presently manufactured offshore, particularly the Far East. To compete with existing established products will be very difficult. The alternative is to develop innovative, cost-competitive products that satisfy the customers' needs.
Software based improvements in the accuracy of measurement of aspherics using a Fizeau interferometer
Authors: Evans Chris J.
Published: February 2023

Modern commercially available phase measuring interferometers (PMIs) can provide, in appropriate environments, repeatability of a few nanometers. A number of authors1,2,3 have described methods which may be implemented on such instruments to provide high accuracy calibrations of flat and spherical optics. Such measurements are typically performed at "null", ie with a single fluffed out interference fringe. In this case, all the optics in the system from the Fizeau reference surface to the detector are common path and hence introduce no significant aberrations.
Cutter Marks as Vibration-Induced Errors in Deterministic Microgrinding
Authors: Lambropoulos John , Golin Don
Published: February 2023

Cutter marks, often referred to as mid-spatial frequency errors during deterministic microgrinding, have been observed on the surface of ground spherical components in a series of experiments at the Center for Optics Manufacturing (COM) at the University of Rochester. A simple model is presented to explain the recent observation that the number of cutter marks N during deterministic microgrinding of spherical components is approximately equal to the ratio of tool rotational rate fT (rpm) to work rotational rate fW for a wide range of these parameters. The model is based on the fundamental assumption that both the tool and the work execute steady-state, forced harmonic oscillations, each at its respective driving frequency, and on the observation that for each revolution of the work, the tool executes fT/fW revolutions.
Enhanced Deterministic Microgrinding on the Opticam SX Using Active Vibration Cancellation Techniques
Authors: Stevens R. Robert , Reimers Ann
Published: February 2023

The Opticam SX grinding machine manufactures optical components quickly and accurately using a computer controlled grinding process. However, characteristic surface errors, referred to as "cutter marks," have been observed on lenses produced by the SX machine. These cutter marks averaged 440 angstroms peak-to-valley in a previous study involving over 100 lenses. In an effort to expand the usefulness of the Opticam microgrinding technique to applications requiring a smoother surface finish, the source of the surface errors and the application of an active control technique to reduce them are being investigated.
Structural Response of Tools in Deterministic Microgrinding
Authors: Pettersson Lars , Lambropoulos John
Published: February 2023

The elastic stiffness and dynamic structural response (in terms of natural frequencies and normal modes) of the tools used in deterministic microgrinding are important design factors which can be controlled via the geometric dimensions of the tool. In this report we use finite element techniques to examine the effects of some of the tool dimensions on the tool structural response under a variety of loading conditions, see Fig. 1.
Deterministic microgrinding of glass with polycrystalline diamond tools
Authors: Funkenbusch P.D. , Zhou Y.Y. , Lohnes C. , Quesnel D.J. , Jacobs S. D. , Puchebner B.E. , Golini D. , Lindquist A.
Published: February 2023

Metal bonded diamond tools have been used at the Center for Optics Manufacturing (COM) for the deterministic microgrinding of glass. With use of metal-bonded 2-4 micron single crystal diamonds in the final grinding step, very smooth surfaces with only a few microns of subsurface damage can be consistently manufactured. While these results are very positive, we are currently seeking means to further improve performance. In particular we are examining the effects of changing the diamond on tool performance.
Infrared interferometric wire test of aspherics
Authors: Anderson David S. , Burge James H.
Published: February 2023

Aspherization of large, fast aspheric mirrors can be guided by an infrared interferometric version of the commonly used wire test. As in the traditional wire test, measurements are made of the intersection of the surface normals with the optical axis resulting in a determination of the longitudinal spherical aberration (and thus, the conic constant) and radius of curvature of the mirror which completely characterizes the shape of the optical surface. In the interferometric test the determination of the surface normal intersection positions are found not by observing a wire but by observing the location in the pupil of the null position of fringes in an IR interferometer having a spherical reference wavefront. Since a 10.6p wavelength is used, the test can be performed on a ground surface. This test was used to guide the aspherization of the 3.5 m, f/1.75 WIYN primary mirror.
Basic Properties of Magnetorheological Fluids for Optical Finishing
Authors: Kordonsky Wm. I. , Prokhorov I. V. , Kashevsky B. E. , Jacobs S. D. , Puchebner B. E. , Hsu Y. , Pietrowski D. , Strafford D.
Published: February 2023

Magnetorheological (MR) fluids are multicomponent systems consisting of a non-colloidal magnetic-dispersed phase in a carrier liquid, which undergo rapid, sharp and reversible changes of their internal structure in an external magnetic field. As a consequence, their rheological properties, such as viscosity, plasticity and elasticity are controllably changed (for example, see Figure 1).
Education in Optical Fabrication in Chinese Universities
Authors: Qiming Xin
Published: February 2023

The education system of optical fabrication in some Chinese universities, such as Beijing Institute of Technology, Zhejiang University, Tainjin University, etc., is given. The main subjects of the textbook in this field taught in these universities are also shown.
Low-load Hardness Behavior of Various Optical Materials
Authors: Cerqua-Richardson K.A. , Ruckart J. , Lambropoulos J. , Fang T.
Published: February 2023

Hardness testing provides valuable information regarding the physical property characteristics of many materials, including infrared glasses and crystalline structures. Data on a material’s mechanical response to an applied load is important in the manufacture of high quality optics which possess low subsurface damage, and high adherence to radius specifications. Visible and infrared optics are currently being fabricated using the capabilities of Opticam, a computer automated machine tool developed at the Center for Optics Manufacture at the University of Rochester. Continuous improvements are being made in the generation of high quality planar and spherical elements, while reducing the laborious and cost-intensive aspects of their manufacture using this CAD/CAM technology.
Establishing a relationship between Static and Dynamic Hardness Testing of Materials
Authors: Cerqua-Richardson K.A. , Ruckart J.
Published: February 2023

Physical property data such as hardness has been used in the manufacture of materials for many years. This information has become increasingly valuable because of the emphasis for continuous improvement in optical quality and its corresponding cost and more recently the emergence of CAD/CAM optics manufacturing technology such as Opticam. Radius of curvature and subsurface damage specifications can be tightly controlled while reducing the need for laborious and cost-intensive manufacture of precision optics, including infrared glasses and crystalline structures.
Use of active optics to optimize the figure of a 3.5-m honeycomb sandwich mirror
Authors: Martin H. M.
Published: February 2023

This paper describes the active support system for the primary minor of the Air Force Phillips Laboratory’s Starfire Optical Range 3.5-m telescope, and in particular the optimization of axial forces after the initial installation of the minor in its operational support cell. The project had as its main goal determining the best set of support forces for the minor. Secondary goals involved characterizing the behavior of the support system, and developing techniques to optimize support forces for 6.5-m and 8.4-m minors, which will have 100-150 actuators as compared with 40 actuators for the 3.5-m minor.