bluuebunny/crossref_metadata_2025 huggingface dataset:
Precision Reflectivity Measurements on Infrared Mirrors
Authors: Anthon Erik , Seddon Ian
Published: February 2023

A measurement system has been developed for characterizing the reflectance of large DF laser mirrors. Measurements are made on both the large mirror and on small witness pieces coated in the same coating run. Precision reflectivity measurements are made on the witness piece and spectrophotometric measurements are made on both the witness and the large mirror. The reflectivity of the large mirror is determined from analysis of the combined data.
Design Considerations of Diamond Turned Optics
Authors: Clark Robert A.
Published: February 2023

The primary design and fabrication parameters by which a diamond turned optic can be specified are categorized as either surface quality or optical figure.
Fabrication Methods and Testing to Meet Specifications
Authors: Grindel Manfred W.
Published: February 2023

Processes and techniques utilized in producing optical elements will include material selection, finishing, coating and testing.
Computer Controlled Optical Figuring at the Optical Sciences Center: An Overview
Authors: Hayes John , Wyant J. C. , Hayslett C. R.
Published: February 2023

Although computers have been used extensively for optical design and analysis, the use of computers to control optical fabrication has been limited to only a few applications. During the early 1970's computer controlled optical figuring machines were developed at Itek and Perkin- Elmer for the in-house production of large diameter mirrors. These machines have been used to produce a number of high quality mirrors and have demonstrated the feasibility of computer control in optical fabrication.
Technique for the Fabrication of a Schmidt Corrector Plate
Authors: Hradaynath R. , Singh H.S. , Dimri G.P.
Published: February 2023

A technique for the fabrication of a Schmidt corrector plate of 200 mm dia and having a maximum sag of 1.2 mm, suitable for use in a F/1 catadioptric optical system has been successfully evolved at IRDE. The profile of the Schmidt surface is illustrated in Fig 1.
Heterodyne Interferometric Analysis System
Authors: Koliopoulos Chris L. , Wyant James C.
Published: February 2023

A heterodyne interferometer system is described which incorporates a two-dimensional CCD photodetector array to provide accurate optical phase measurements of a wavefront at each of its 244 by 190 detector locations. The intensity of each detector is digitized and read directly into the memory of a Data General Eclipse computer at a rate of approximately 2.5 x 106 pixels per second. The phase is calculated using the 3-bucket technique described below. The basic interferometer is a Twyman-Green (LUPI). A 320 x 240 element 16 grey level or color graphics display helps in quickly accessing figure quality from the map of calculated phase values.
Methods for Measuring the Apparent Optical Figure and Reflectance Uniformity of a Multilayer-Coated Mirror
Authors: Bennett H. E. , Burge D. K.
Published: February 2023

If a diffraction-limited wave front is to be produced by an optical train, the requirements on the optical figure of individual mirror components may be very stringent. Values of λ/8 visible equivalent are common for infrared systems, and λ/100 visible equivalent has been suggested for some ultraviolet systems. The optical figure of multilayer-coated optics is determined not only by the geometrical perfection of the optical surface of the mirror but also by the uniformity in thickness of the multilayer coating. The question then arises of how to tell if a multilayer coating is uniform enough not to degrade the mirror surface on which it is coated to below optical figure specifications. The peak mirror reflectance is also of interest and is often difficult to accurately measure directly. It varies far more slowly with variations in film thickness than does the optical figure, as seen in Fig. 1, but is very sensitive to variations in film absorption coefficients. The optical figure of a coated part can be determined interferometrically, but the interferometric measurement must be made at the wavelength at which the coating is to be used. Alternate techniques are to measure the secondary structure surrounding the reflectance maximum or to use ellipsometry at the design wavelength. Typically, the ellipsometric parameter ψ is insensitive to variations in film thickness but quite sensitive to absorption in the film. The converse holds for Δ, as seen in Fig. 2. For a representative infrared high-reflectance multilayer coating, a measurable change in ψ corresponds to a change in peak reflectance of 0.001, and a measurable change in Δ corresponds to film thickness nonuniformities of less than 0.01%. An automatic ellipsometer could be readily used to scan the surface of even a large mirror. Ellipsometry may thus provide the optimum technique for testing mirror optics for reflectance uniformity and multilayer-film- induced changes in apparent optical figure.
A Method Determining the Curvature of Weak Surfaces
Authors: Lawton Kenneth C.
Published: February 2023

Accuracy in determination of the curvature of surfaces with radii greater than 2.5 meters, or with numerical apertures smaller than .01 is difficult. Methods of fringe counting against a flat, sagitta measurement, or using improvised test benches yield results with low precision.
When to Use and How to Specify Glass Pressing
Authors: Baker Terry
Published: February 2023

The molding of lens blanks has developed over the years into a highly sophisticated and exacting art.
Lathe for Generation of Aspherical Surfaces of Revolution
Authors: Watt Gordon J.
Published: February 2023

This paper discusses various types of diamond turning machine currently in use and compares their geometry to the aspherical generator developed at Kollmorgen. Typical aspheric optical surfaces are discussed and a normalized mathematical formulation derived. Specifications for the desired surface as applicable to single point machining are suggested. Methods of qualifying the surface are presented. The Kollmorgen aspheric measuring machine is described.
Trends in Fabrication Processes for Production Optics
Authors: Fantone Stephen D.
Published: February 2023

The term production optics is a rather broad one and there are probably as many definitions of it as there are people in this meeting. From my own experience I have found that for some manufacturers production levels of more than 10 pieces a day are considered high volume, whereas some production levels of 10 pieces per day are decidedly low volume. The distinction between high and low volume depends upon the particulars of any fabrication job: the materials, the technology involved, the accuracy and tooling requirements, the capabilities of the workforce, and cost limitations.
First Order Calculations for Coatings
Authors: Thomas Norman L.
Published: February 2023

Most experienced coating facilities have a collection of coating designs that were successfully coated in the past. These designs can be shifted in wavelength and corrected for dispersion, or shifted in design angle to satisfy different requirements. In many cases, a new design may be necessary to achieve the required goals. Although there are a limited number of useable coating materials that can be used in a specific wavelength region, there usually exists several coating designs, not all of which are practical, to satisfy a given coating requirement. Thin film optimization computer programs are used to obtain a final design from the first order design by taking account of dispersion, absorption, etc. Optimization programs usually "home in" on the nearest solution to the starting design that satisfies the requirements. The first order calculations play a central role in coating design and determine the direction for optimization. This paper attempts to cover some methods of first order coating designs that can later be optimized by trial and error, or with an optimization program.
Applications for Phase Interferometers: An Approach to Absolute Accuracy
Authors: Keenan Peter B.
Published: February 2023

The accuracy requirements for interferometric testing of optical components has become increasingly severe in the past few years. There are two primary reasons for this trend. First, fringe scanning interferometers coupled with rapid, accurate digital processing have provided impressive levels of measurement resolution and accuracy. The second driving force is the construction of large systems containing on the order of one hundred surfaces with a transmitted wavefront specification of a fraction of a wavelength.
Automated Scatterometer for High Quality Optical Surfaces
Authors: Schlair Rami , Truax Bruce E.
Published: February 2023

The design of an automated scatterometer for production testing of high quality optical surfaces is presented.
Rapid Assessment of Midspatial Frequency Figure Errors
Authors: Wong N. C. , Parks R. E.
Published: February 2023

Bright and dark ringlike intensity variations in the out-of-focus images of the Multiple Mirror Telescope have been observed and it has been suggested that this is due to zonal figure variations in the primary mirrors. We present a geometrical optics analysis that accounts for this phenomena. The analysis also yields an equation for the out of focus image brightness variations in terms of the spatial frequency of the zonal error.
The Design of an 8 m Polishing Machine
Authors: Parks R. E. , Campbell H.
Published: February 2023

Before describing the design of a new large optical polishing machine, we will discuss some of the shortcomings of traditional large polishers. Most large polishers are scaled up versions of Draper type machines which use "trombone" arms to carry an eccentric motion of a crank into a stroke at the poker pin. The structures that support the crank and far end of the trombone take up easily as much floor space as the polishing table itself. For a 2 or 3 m polisher this loss of floor space can be overlooked. For an 8 m polisher we had to see if there wasn't a more efficient design.
Materials Properties Influence on Smoothness of Diamond-Turned Electroless Nickel
Authors: Syn C. K. , Saito T. T. , Taylor J. S. , Donaldson R. R.
Published: February 2023

Electroless nickel is an attractive material for optical components since i) it has a high hardness among the diamond-turnable materials, reducing the incidental damage and easing the task of optical polishing if it is required subsequent to diamond-turning, and ii) it can be deposited on many substrate materials as is frequently practiced in optics fabrication. Diamond machining experience, however, has shown a wide range of surface finish and tool wear, indicating a need for a better understanding of the machining process and the effects of material properties on the surface finish.
Performance of an Infrared Phase-Shifting Interferometric System
Authors: Stahl H. Phil
Published: February 2023

An infrared phase-shifting interferometric system has been developed at the University of Arizona Optical Sciences Center. It is a compact, self-contained, easy to align and operate, next generation optical shop instrument. The principle applications for an infrared interferometer are: 1) inspection of infrared materials in transmission for index homogeneity and internal defects, 2) interferometry of surfaces, such as an asphere, whose slopes are too steep for the fringes to be resolved by a visible interferometer, and 3) interferometry of surfaces that are too rough to be tested at visible wavelengths. The advantages of operating an infrared interferometer in the phase-shifting mode are: 1) improved wavefront phase measurement accuracy and resolution 2) the measurement is independent of the beam irradiance distribution and the interferogram fringe contrast, and 3) the wavefront can be sampled and analyzed rapidly over a large two dimensional area.
A method of interferogram interpretation.
Authors: Pinto Giuliano , Vietri Gabriella
Published: February 2023

A method for evaluating the performance of an optical system has been developed. The method is based on a comparison between the actual wavefront as measured at the output of the optical system under test and a simulated wavefront corresponding to the nominal system. In this way information regarding fabrication related defects can be obtained, in other words the difference in performance between the actual system and the nominal system corresponding to the design prescription can be appraised.
Contouring with the Large Optical Generator
Authors: Parks R.E. , Lam S.S. , Kuhn W. , Ketelsen D. , Kittrell W.C.
Published: February 2023

The Large Optical Generator (LOG), a computer numerically controlled vertical grinder has been used to generate a convex off-axis segment of an f/0.35, 10 m parent paraboloid. The segment subtends 45° of arc and has inner and outer radii of 350 and 1975 mm respectively. Overall dimensions of the segment are about 2x2x0.12 m.
A Component Technology for Single-Mode Optical Networks
Authors: Millar C A , Mallinson S R
Published: February 2023

We report a single-mode micro-optic technology which has proved to be an indispensible foundation for single-mode optical network components. The starting point for a generic micro-optic approach has been single-mode connector fabrication technology. In this, a single-mode fibre is mounted in a ferrule and the outer diameter machined concentric with the fibre core1. Shape Memory Effect (SME) metal2 sleeves are used to automatically and rigidly align the axes of two fibre cores. An hermetically sealed, ruggedized connector, with losses of around 0.5 dB, results3. Machined ferrules containing plano-convex micro-lenses may be introduced into common SME sleeves to provide collimated beams from the fibres. Total insertion losses as low as 1.4 dB have been achieved, with improvements to 0.8 dB likely. Single-mode collimated beam devices, such as in-line filters, polarizers, modulators etc, can be demonstrated (Fig 1).
Beyond Optical Design: Interaction Between the Lens Designer and the Real World
Authors: Thompson Kevin P.
Published: February 2023

The principal responsibility of an optical designer is to provide an optical system, on paper, which exceeds a set of requirements. During the design process it has also become increasingly important to desensitize the system to manufacturing errors. Continuation of the desensitization process beyond the paper design can greatly enhance the manufacturability of a system. Insight into the properties of the optical system, developed during the design and sensitivity analysis, can be used to provide important inputs to the processes chosen to fabricate and assemble high performance optical systems.
Portable Infrared Stiumulus for the Halogen Occultation Experiment
Authors: Payton M. E. , Burcher E. E.
Published: February 2023

The testing of the Halogen Occultation Experiment (HALOE) requires that a source simulating the sun be available during various tests. This source must be able to be moved from one test area to another, and also be used in a thermal/vacuum chamber during environmental testing, The Portable Stimulus Test Set (PSTS) was designed to meet these criteria. The PSTS consists of a modified blackbody and an off axis parabolic mirror used together to produce a 10-inch collimated beam. The off-axis parabolic mirror blank, composed of aluminum, was machined on numerically controlled equipment. Because of the backlash of the mechanical gears, the mirror blank had a small step in it where the gear direction changed. This "step" was then hand-worked until the surface features were within 0.5 mil. of the desired features. After the surface features were within 0.5 mil., the blank was nickel plated and worked until the surface features gave λ/4 at 6328 Angstroms. When the nickel plated surface was λ/4, a hard gold coating was applied. A technique for improving the numerically controlled machining is discussed.
Direct Phase Measurement of Large Optics with a Compact Interferometer
Authors: Anderson D.S. , Cao G.R. , Koliopoulos C.L.
Published: February 2023

The requirements on figure quality of large optics, particularly in the mid to high spatial frequencies have pushed beyond the limits of resolution of some common wavefront analysis methods such as the reduction of interferograms. The smoothness requirement for some astronomical mirrors on spatial scales of a few centimeters is on the order of .01 Arms making fabrication and testing of these mirrors difficult. The advent of direct phase measuring interferometry with the use of high density CCD or photodiode arrays has provided a means to achieve the necessary resolution.
Selection of Materials and Processes
Authors: Grindel M. W.
Published: February 2023

The tutorial will be on the company owner's view in the selection of materials and processes for the manufacture of optical components, coatings, and sub-assemb1ies. It will start with the receiving of a quotation from the customer. Depending on the quantity requirements, either prototype quantities or large volume production quantities, it will have to be determined how to buy raw materials and a decision will have to be made on temporary or hard tooling. We will show a comparison of different manufacturers suppling the same type of raw materials and their impact on quality, price, and delivery. We will discuss interfacing between engineering or designers and manufacturers. A cost comparison will be made between single elements and large volume production. We will also discuss the effect of tolerances on pricing. One would also have to look if test equipment is available or will have to be modified or possibly purchased. Specifications will be discussed to establish coating parameters. We will also discuss the impact that quality, environmental requirements, and change orders have on delivery.
Construction of Pitch Laps for Constant and Nonconstant Radius Work
Authors: Brown N. J.
Published: February 2023

Summary not available.
Fabrication of Fused Silica Surfaces with Controllable RMS Roughness and Correlation Length
Authors: Zavislan James M.
Published: February 2023

A fabrication technique is described for producing fused silica surfaces with controllable rms roughness and correlation length. The rough surfaces are generated by coating a fused silica surface with Shipley 1400-17 photoresist and exposing the photoresist to a laser speckle pattern and a coherent reference beam. The photoresist is developed and the structured photoresist surface is eroded into the fused silica surface with an argon ion mill. The rms roughness of the resulting surface is controlled by the exposure energy and development conditions. The correlation function of the surface is related to the Fourier transform of the intensity distribution that produces the speckle pattern. The surface height distribution is a function of the ratio of the reference beam irradiance to the speckle beam irradiance.
Viscous Forming of Lightweight Mirror Blanks
Authors: Keim R. E. , Papadopoulos K. , Vallimont J. A. , Wylot J. M. , Pledger J. R. , Blair (Retired) G. E.
Published: February 2023

Although the technology of thermal fusion bonding of glass elements is well know and fusion welded mirror blanks have been in existence for decades, the current manufacturing process has been costly and time consuming. There are valid and defendable reasons for this current condition which generally relate to the near-custom and low volume demands of the industry. Basically, there has never been a need to "mass produce" silica lightweight mirror blanks.
International Standardization of Optical Coatings
Authors: Guenther Karl H.
Published: February 2023

In the U.S., the industrial development of optical coating technology was mostly driven by military and space requirements. Naturally, de-facto standards grew out of military specifications, which are fairly comprehensive and still widely accepted also for nonmilitary applications, both in the U.S. and overseas. So, why do we need new international standards at all?
Precision Glass Molded Optics
Authors: Pollicove Harvey M.
Published: February 2023

Precisely molded Glass Spherical and Aspheric optical elements are a fairly recent development in optics manufacturing. This paper will describe the various techniques developed to mold glass lenses, with application examples given for each method. A worldwide survey of known commercial availability and very recent developments at Kodak to demonstrate the potential of the precision glass molding technology are reviewed. Precision Glass Molding (PGM) at Kodak has been extended from Spherical and Aspheric lens molding to non-symmetrical optics. Even more recently radiation hardened glasses, glass-based infrared materials, and laser glasses have been molded. Since the molded optic precisely replicates the tool, features on the optic can be utilized to more easily align aspheric and non-symmetrical optical elements into the optical system. Transmitted wavefronts of better than 0.05 waves rms are achieved with a single aspheric lens. Overall performance of the single element lens system is typically superior to a three-element spherical lens system when field performance, magnification control, and actual N.A. control are considered.
High Precision Optical Profilometer Using the Differential Method
Authors: Miki H. , Suzuki N. , Adachi M. , Nakai Y. , Kawaguchi I.
Published: February 2023

A scanning type optical precision profilometer is proposed. By Calculating the difference of the measured height at a point and its surrounding areas, it gives the roughness profile nearly independent of vertical vibrations. The height variation of a point and areas are measured from the interfered light intensity variation using a photomultiplier tube and three Si photo diodes arranged on the image plane of the interference microscope. The performance of the profilometer is checked from the roughness measurements of the aluminum substrate for hard disc, the aluminized optical flat, a Si-wafer, and the step standard calibrated by a stylus instrument. As a result, the reproducibility of 0.5nm was verified and the step height at the grain boundary of diamond-turned aluminum disc was measured as about 2.0nm. The errors, caused by the distribution of the slight reflectivity, were reduced by using the dual polarized light interference method. The filtering effect on the profile determined by the sensor arrangement is calculated and corrected by the digital signal processing. By this correction, not only the precise roughness profile but also, the figure profile can be measured independently of vertical vibrations.
Pad Polishing for Rapid Fabrication of Flats
Authors: Berggren Ralph R. , Schmell Rodney , Lazazzera Vito
Published: February 2023

Flat or mildly curved mirrors are required in very large quantity for the Inertial Confinement Fusion (ICF) Program, an active program at Los Alamos National Laboratory. The ultimate system will require in excess of 1,000 square meters of mirror surface. The mirrors direct the energy from a large number of laser amplifiers, using many separate beams per amplifier, to the target, which must be illuminated evenly from all directions.
Development of Single Point Turning Technology for Beryllium Mirrors
Authors: Arnold Jones B. , Morris Thomas O.
Published: February 2023

Single point diamond turning techniques have been developed and
employed to produce a variety of nonferrous metal mirrors. These
techniques have not been effective for turning beryllium. Because of
the unique properties of beryllium to military applications and the
advantages of single point turning, a development program has been
instituted to single point turn beryllium.2 Tool materials,
cutting fluids, and machining parameters such as spindle speed, feed
rate, depth-of-cut, and tool geometry have been evaluated, resulting
in a significant improvement in the machining process. Tool wear has
been the primary limitation in precision machining beryllium, but
advances have allowed a two order-of-magnitude reduction in this
problem. The safety aspects of machining beryllium are crucial and
have also been addressed in this program.
Measurement of the homogeneity of optical materials
Authors: Hunter George C. , Sutton Larry J.
Published: February 2023

The measurement of the homogeneity of optical materials is discussed. Methods and equipment for evaluation of both polished and unpolished material samples are described.
Establishment of a BRDF Standard Measurement Practice
Authors: Leonard Thomas A. , Reilly James
Published: February 2023

Nation-Wide BRDF round robin results at 0.6328 and 10.6 um showed the need for standardized scatter measurement/reporting procedures within the optical community. ASTM subcommittee E12.09 was formed in 1988 to address this need. This presentation reviews the round robin results, the work of E12.09 to promulgate a BRDF Standard Practice and work on a 10.6 um physical scatter reference.
Specular Reflectometry at Variable Angles
Authors: Gallagher Robert A.
Published: February 2023

Most traditional methods of measuring specular reflectance rely on high mechanical precision of the measuring fixture and/or on the use of a calibrated reflectance standard. In addition, many of these methods measure reflectance at only one angle of incidence, usually near normal incidence. This presentation will describe simple fixtures and calibration methods for performing spectral measurements of specular reflectivity over a broad range of incidence angles, Computerized data acquisition and manipulation are an essential aspect of this approach.
Aligning Diamond-Turned Optics Using Visible-Light Interferometry
Authors: Figoski John W.
Published: February 2023

An initial attempt was made applying spatial filtering to the point image of the return wavefront. This image showed a pronounced bowtie diffraction pattern generated by the concentric circular arcs of the pupil function. By experimenting with circular pinholes of various sizes we were able to smooth the wavefront dramatically. Wavefront slope errors were reduced from 0.015 waves/mm to 0.005 waves/mm. Results of this experiment will be presented and other questions raised by this attempt will be discussed.
Power Spectrum Standard and Examples
Authors: Janeczko Donald
Published: February 2023

Power spectrum characterizes the performance of so-called "perfectly" polished surfaces. It's use, tips, tricks, traps, and examples will be discussed, including TIS, BRDF, and Ra.
Angstrom-level Calibration of Eight Inch Flats using a Scanning Fizeau Interferometer
Authors: Anderson A. , La Fleur L. D. , Kasserls M. , Zweig D. A.
Published: February 2023

A scanning Fizeau interferometer is used to measure a set of eight inch reference flats. The uncertainty in the measured figure is less that 2 Årms.
Deterministic Microgrinding
Authors: Golini Donald , Czajkowski Walter
Published: February 2023

The Center for Optics Manufacturing Process Science group has produced optical surfaces with little subsurface damage and exceptional figure accuracy using a newly developed deterministic microgrinding process. The process can generate a specular diamond ground optical surface in five minutes. The ability to microgrind high quality optical surfaces quickly, advances the state of the art in optics manufacturing. The results are notably significant, as the samples produced meet the two most critical criteria for deterministic microgrinding: low subsurface damage and high figure accuracy.
Evaluation of phase shift, misalignment, and propagation errors in Fizeau interferometry
Authors: Huang Chunsheng
Published: February 2023

Three error sources, phase shift accuracy, misalignment of the test surface, and wavefront error propagation in the imaging system of an interferometer are analyzed in this paper. The phase shift error addressed here is not caused by poor repeatability [1-4] of the PZT (piezoelectrical transducer) but by transverse phase variations due to its curved Fizeau cavity when the test or Fizeau element is translated. Misalignment of a curved surface under test is due to the fact that fringes are not completely nulled. Tilt and power or defocus can introduce coma and spherical aberration errors which are not insignificant to the interferometer accuracy. For example, a half wave of defocus of a test surface with a NA of .5 can produce a 10th wave of spherical aberration error in the measurement and a half wave tilt of the same surface can create an 8th wave of coma error. The propagation error results when a test wavefront is sheared with a reference wavefront in the imaging system of the interferometer.
Electrical Assisted Grinding of Precision Glass and Ceramic Parts
Authors: Polvani R.S. , Evans C.J.
Published: February 2023

We are developing better ways of making precision glass and ceramic parts. Two recent parts are subsurface damage free SiN MOR bars and RBSiC aspheric optics. If, in the past, we relied on resinoid bonded super abrasives; our focus now is on metal bonded wheels. Already, our experience demonstrates their promise - much better figured and finished parts, and a hazard. The performance is tied to stringent preparation beforehand and in-process dressing to insure free cutting. We grind using a modified Blanchard; the spindle is tilted off axis by 1 degree. The 4 inch cup wheels run up to 6000 SFM. We found less than 0.2 micrometer total axial runout to be a working requirement. Further, the wheels - without appropriate dressing - quickly clog or load with debris. Free cutting requires continuous dressing.
Opening Remarks and Workshop Overview
Authors: Selberg Lars A.
Published: February 2023

Summary not available.
Surface Errors Due to Static Tool Misalignments in Deterministic Microgrinding
Authors: Quesnel David , Rich Timothy , Lambropoulos John
Published: February 2023

The proper alignment of the tool and the workpiece in a curve generator is essential for manufacturing precision optics. Misalignments result in deviation from the desired shape of the lens. We summarize the development of desktop software which predict the amount of deviation of a generated spherical surface from a perfect sphere in terms of the misalignment between the axes of the tool and the workpiece. The software can be used to create a database correlating surface errors and axes misalignments. Such a database is of use to operators of curve generating machines, such as the Opticam SM and Opticam SX, who may thus be able quantitatively to predict the amount of correction required to remove a given amount of surface error.
Influence of Process Parameters in Deterministic Microgrinding
Authors: Golini Don , Lindquist Arne , Atwood Mark , Ferrera Custodio
Published: February 2023

The expanded capabilities of the Opticam equipment have resulted in the introduction of a new regime of machining of brittle materials, called deterministic microgrinding. Optical components are deterministically microground to a very high level of form accuracy (1/5 wave peak to valley) and surface finish (50 Angstroms rms) using a repeatable and predictable computer controlled process. This is a result of the introduction of precision machine tools to optics manufacturing. The surface finish being achieved on optical glass is unprecedented using a production oriented process (cycle time of 10 min./surface) There remains substantial work to be done in understanding and optimizing process parameters for deterministic microgrinding of a wide range of optical materials. A comprehensive process parameter study is being carried out on all of the Opticam machines, including in depth development studies of feeds and speeds, material, tool, and coolant properties, and machine characteristics. Following is a brief description of some results to date.
Robust Metrology for Large Optics featuring the Improved Foucault Test Approach
Authors: Vandenberg D. E. , Wertheimer Alan
Published: February 2023

Results of tests will be presented that demonstrate the Improved Foucault Knife Edge Sensor's ability to sense wavefront deviations and provide surface data for closed loop correction of an optical telescope with a segmented primary mirror.
Environmental and safety concerns In the optical shop
Authors: Karow Hank H. , Bohrar Rich
Published: February 2023

Environmental laws and safety rules are Intended to create a safe work environment. This paper will examine how the handling of chemical agents and their use in the optical shop from receiving to waste diaposal must be carefully controlled.
Chlorofluorocarbons in the Workplace: A Summary of Guidelines and Alternatives
Authors: Puchebner Birgit E.
Published: February 2023

The Montreal Protocol on Substances That Deplete the Ozone Layer mandates an end to the industrialized countries' production of chlorofluorocarbons (CFCs), carbon tetrachloride, and methyl chloroform by January 1, 1996. This treaty effects everyone from the CEO of a top chemical producer to the next door neighbor driving to work everyday.
Fabrication of "Green" IR Optics
Authors: Cerqua-Richardson K.A. , Vakiner J.
Published: February 2023

Material manufacturers and fabricators are becoming increasingly aware of environmentally-friendly growth, melting and finishing procedures being implemented throughout the domestic and international optics market. The "green" policy which is emerging requires material handlers to stringently adhere to numerous procedures and regulations in the hope of reducing the use of ozone-depleting coolants and solvents, the amount of heavy metals entering waste water systems, and controlling the disposal of residue and waste slurry from toxic materials.
Precision Asphere Fabrication and Metrology to Tolerances <1 nm RMS
Authors: Kestner Robert
Published: February 2023

Summary not available.
Sapphire Grinding Study
Authors: Golini Don , Lambropoulos John , Atwood Mark , Smith Maynard B. , Schmid Fred , Khattak Chandra
Published: February 2023

Sapphire missile domes and plane parallel optical windows have had important military applications for many years, yet have been plagued by high manufacturing costs, primarily due to the material’s extreme fracture toughness, microhardness, abrasion resistance and critical load. Simply put, the attributes that make sapphire an attractive window material, also make it quite difficult to grind. In addition to its useful mechanical properties, sapphire has excellent thermal shock resistance, chemical stability at high temperature, a melting point in excess of 2000 degrees C, and good transmission from the UV through 3-5 microns. Studies to optimize precision microgrinding of sapphire will not only lead to more affordable tough durable multi-spectral military windows, but also will aid in an improved understanding of the grinding process for all optical materials.
Development of grinding wheels for optics
Authors: Picone Joseph E.
Published: February 2023

The glass and technical ceramic market has been using the same manufacturing process to finish their components for the past 50 years. The presumption is that all glasses fall within the medium to low range of MOR values and can be readily ground with metal bonded diamond wheels, and that all grinding operations cause microfracturing that must be corrected by subsequent operations, like lapping and polishing.
Progress towards improving glass grindability: a glass chemistry approach
Authors: Richardson Kathleen A. , McKinley Jennifer , Clare Alexis G. , Ott Adam
Published: February 2023

Optical glasses have traditionally been selected for use in optical systems based solely on their optical properties, specifically refractive index and dispersion. Ideally, one would like to select an optical material with desired optical properties and the knowledge that it can be easily fabricated using conventional or advanced fabrication techniques with good figure accuracy, low microroughness and subsurface damage. These three criteria have been identified by researcher’s at the Center for Optics Manufacturing (COM) as a benchmark to assess workpiece quality following fabrication using the Opticam family of machine tools. The commercially available machine tools developed at COM with the American Precision Optics Manufacturer’s Association (APOMA), are currently used in industry to fabricate a wide range of optical materials in spherical, aspheric, plano and most recently micro geometries. Research in the science of optic manufacturing has addressed numerous material and tool related questions, including why under identical machine and tool processing conditions, some glass types grind to a high quality finish, while others reproducibly yield high roughness, high damage surfaces. It is our response to this question which forms the basis of this paper.
Monitoring lap forces during final polishing of the MMT 6.5-m honeycomb mirror
Authors: Allen Richard G. , Dettmann Lee R.
Published: February 2023

The new 6.5-m honeycomb mirror for the Multiple Mirror Telescope Observatory on Mt. Hopkins was polished with a 1.2-m stress lap on the Large Optical Generator at the Steward Observatory Mirror Lab. Problems during the last few months of polishing led to the development of a system for monitoring the drag forces on this lap. Records of the drag forces during each stroke were then used to compute an effective drag coefficient as well as the frictional power dissipated per unit area of mirror as a function of radius. While the glass removal rate was found to track the observed distribution of expended frictional energy quite nicely, the system turned out to be even more valuable as a tool for identifying anomalous drag conditions before they put a significant imprint on the mirror.
Modern lens design using a lens manufacturing database
Authors: Tienvieri C. Theodore , Rich Tim
Published: February 2023

Computer data bases are not a new concept to the lens design community, several optical design oriented data bases have been written to assist the lens designer in searching for lens starting points. This paper will discuss the benefits of a manufacturing oriented data base to the optical designer.
Plasma-Enhanced Chemical Vapor Deposition of Optical Interference Coatings
Authors: Lee J. C.
Published: February 2023

In recent years, plasma-enhanced chemical vapor deposition has found increasingly numerous practical applications, particularly in the microelectronics industry. Specific examples include the commercialized silicon nitride deposition reactors for metal oxide semiconductor (MOS) device passivation and dielectric isolation, and the experimental silane reactors various workers have constructed to research the potential of plasma-deposited amorphous silicon thin films. However, with the exception of rugate filters, relatively little work has been done on fabrication of optical interference coatings by chemical vapor deposition (CVD) techniques of any sort. This paper describes a plasma-enhanced CVD technique designed specifically for just this application, i.e., optical interference coating fabrication. Moreover, as will be described in more detail, it is a technique particularly well-suited for coating plastic substrates with complex coatings, which has always been a challenging coating problem.
Effects of Deposition Parameters on Optical Properties of Ta2O5 Films Deposited Ion-Beam-Sputtering
Authors: Demiryont H. , Sites J. R.
Published: February 2023

Ion-beam-sputter deposition parameters of Ta2O5 films were investigated for using them as an optical coating material. Optical parameters of the films were found to be a sensitive function of oxygen fraction in the beam and total gas pressure during deposition. An oxygen fraction of 20% or higher in an Ar-O2 mixture produced non-dispersive oxide films in the visible and infrared region of the spectrum. Refractive index of the samples were found to be in the range 2.05 - 2.15 and extinction coefficients to be 10-5 - 30 × 10-3 depending on both oxygen fraction and wavelength, λ (0.4< λ (μ) <2.0).
Computer Aid in the Operation of an Optical Coating Lab
Authors: Songer Larry
Published: February 2023

As a viable alternative to large capital outlay for a "completely automated" coating machine, the purchase of a small computer with appropriate programs can be used successfully in the production of very complex optical coatings. The most common misconception of using a computer in a coating lab, is that all that is needed is a program that can compute the spectral properties of a given design (and, hopefully, have a refinement routine built in). The other misconception is that the program must be extremely fast.
Thin Film Deposition Monitoring With An Automatic Ellipsometer
Authors: Tirri Bruce
Published: February 2023

Conventional thin film deposition monitoring techniques in use today have several limitations. They generally give information on either mechanical thickness (quartz crystal monitoring) or on optical thickness (photometric monitoring) but not on both simultaneously. These techniques usually require extrapolation of the thickness being deposited on a remote substrate (or crystal) to the thickness being deposited on the substrate to be coated. Errors arise due to changing process parameters such as vapor distribution patterns, temperatures and pressures.
Design of non-polarizing prism beam splitter
Authors: Chang Lin Yong , Mo Sun Hsiao
Published: February 2023

In this paper we discuss designing method of the D-M-D three layer for non-polarizing prism beam spilitter at incidence. First we design metallic film: Selecting complex index of metallic film is based on the principle which is must possessing the effect of depolarization and broad spectrum level for R or T. According following formala: where Rp,min is minimum of P-component in reflection. It shows the higher the ratio of k/n is, the higher the Rp,min and the lower the polarizing effection in visible spectrum, we all know Ag has the highest k/n value, better spectrum level in visible region so we choose Ag as non-polarizing metallic film.
Coatings for Ophtalmic Lenses
Authors: de Lega A. Colonna
Published: February 2023

The correction of VISION defects basically requires to provide to the patient an optical device giving a specified "optical power" (dioptric).
Thickness Distribution of Evaporated Films
Authors: Musset Anthony , Stevenson Ian
Published: February 2023

In order to set up a vacuum chamber for coating a number of large parts, or perhaps a large number of small parts, it is of importance to know the emission characteristics (source function) of the evaporation source.
Topographic Evaluation of Optical Thin Films by Hologram Interferometry
Authors: Salazar David , Tentori Diana
Published: February 2023

Interferometry is a very powerful technique since it allows us to obtain a two dimensional mapping of the optical path distribution across the field of observation.
Multilayer and Variable Index Coating Deposition by Automatic Ellipsometry
Authors: Tirri B. , Dunn D. , Vanbuskirk P.
Published: February 2023

Automatic ellipsometry is very useful as a monitoring instrument due to its accuracy and precision. Application to several classes of thin film designs of this approach will be described.
X-Ray Metal Film Filters at Cryogenic Temperatures
Authors: Keski-Kuha Ritva A.M.
Published: February 2023

In the X-ray and ultraviolet spectral region thin metal foil filters are used extensively both in laboratory and space applications near room temperature. The X-ray spectrometer (XRS), which is being developed for one of the focal plane instruments of the Advanced X-ray Astrophysics Facility (AXAF), requires filters with high X-ray transmittance and also high background rejection, operating at cryogenic temperatures. The operating temperature is between 1.5K-245K, and will vary for each filter in the assembly. Thin metal foil filters can provide high X-ray transmittance and also the required rejection for low energy radiation. However, thin metal foil filters have not been used at cryogenic temperatures and, therefore, their performance and survivability in this environment has to be evaluated.
Young’s Experiment at Lambda = 1.54 A Using Sputtered-Sliced Multilayers
Authors: Thomas Norman L. , Bionta Richard M.
Published: February 2023

We will discuss our technique for producing sputtered-sliced zone plates and transmission gratings. Both amplitude modulated and phase modulated devices have been produced. These devices have been used to demonstrate interference effects with 8 Kev xrays in our lab.
Reality and Limits of Spectroscopic Ellipsometry
Authors: Stehle J.L. , Bernoux F. , Thomas O.
Published: February 2023

Ellipsometry is widely used for measurement of thin films. Usually instruments can only give index of refraction and thickness of one transparent layer at one wavelength. In order to know more about the layer two techniques have been developed recently; one is exploration of the spectral information covering the useful range from .23 up to 1.7μm. The multiplicity of information all along the spectrum enables smart calculations using various models to explain a posteriori the history of the layer growth. The other way is to follow the etching of the surface and the growing of a film in Situ, in real time. For this purpose only a well chosen wavelength has been used, occasionally two or three wavelengths are studied at the same time.
Affects of Vacuum Exposure on Stress and Spectral Shift of High Reflective Coatings
Authors: Stolz C. J. , Taylor J. R. , Eickelberg W. K. , Lindh J. D.
Published: February 2023

When designing an optical system it is imperative that the optics be characterized in the operating environment. In order to maximize transport efficiency an understanding of spectral shift is necessary to optimize incident angles of polarizers and dichroics. Likewise, changes in reflected wavefront due to vacuum can effect beam sizes and image locations as well as transport efficiency.
Optimisation Procedures Using the "Eye" Merit Function
Authors: Piegari Angela , Emiliani Gabriele
Published: February 2023

In the design of optical coatings the desired performance is continuously compared with the calculated values.

When the comparison between two curves is made over a wide wavelength range an immediate evaluation of how much the calculated curve approaches the desired one can be obtained simply overlappping the two graphs and looking at them. That means the eye makes its own total evaluation that in most cases represents the best judgement. In general the similarity of two curves is evaluated by a merit function that compares them in a number of chosen points (wavelengths) where the difference between the two values is calculated. The choice of these points and of their number is often very critical and requires a great experience.
On the appliability of the Kramers-Kronig relation to the determination of layered media optical parameters
Authors: Tikhonravov A.V. , Poezd A.D. , Zuev I.V.
Published: February 2023

The Kramers-Kronig relation (KKR) is widely used to determine optical parameters of the bulk materials. It allows to restore amplitude reflectance from the energy reflection coefficient measured in a wide spectral band and thus to receive at every wavelength two simple equations for refractive index real and imaginary parts determination1. In the case of reflection from bulk material surface correctness of the KKR is the sequence of the fundamental physical properties.2 These properties prescribe that amplitude reflectance zeros must be located in the lower half-plane.
Surface Plasmon Measurements of In2O3:Sn Thin Films
Authors: Lehan J. P. , Sprague R. W.
Published: February 2023

We have applied a He-Ne laser operating at 3.39 microns to probe the microstructure of thin films of In2O3:Sn by observing their surface plasmon characteristics. The results of the surface plasmon measurements will be contrasted with theoretical results calculated using the Drude model from measured DC electrical properties. Discrepancies between theory and experiment will be explained in terms of film microstructure.
Liquid Crystal Light Valve with fast responce time and high contrast ratio
Authors: Tang J.F. , Gu P.F. , Liu X. , He X.T. , Mei T. , Li H.F.
Published: February 2023

The liquid crystal light valve (LCLV) is an optical-to-optical image transducer that is capable of accepting a low-intensity visible light and real time converting it into an output image of the light from another source.