bluuebunny/crossref_metadata_2025 huggingface dataset:
Photo-Activated Phase Transition In Antiferroelectric Thin Films For Optical Switching And Storage*
Authors: Wang Feiling , Haertling Gene H. , Li Kewen K.
Published: February 2023

An electric field induced antiferroelectric (AFE)-to-ferroelectric (FE) phase transition in lead zirconate titanate (PZT) thin films was shown to produce a digital birefringent change in the materials. Such field-induced AFE-to-FE phase transitions may be influenced by the interface between the PZT thin films and certain electrode materials. It has been observed that soft-ultraviolet (UV) illumination to PZT thin films effectively lift the interfacial suppression to the phase transition. Therefore, soft-UV light may be used as a writing beam to change the polarization state of the PZT thin films via the photo-activated AFE-to-FE phase transition.
High Density Optical Disk Mastering
Authors: Katsuda Shinichi , Ishizuka Kenichi , Ohmura Naoki , Yamada Kazuhiko
Published: February 2023

For realizing high density CD-ROM media, it is necessary to decrease pit width, as well as track pitch. However, there are great difficulties involved in fabricating a narrow pit width using a conventional masterwriter with 457.9-nm-wavelength, Ar light source1-3). This paper describes 363.8-nm-wavelength UV light source application for high density mastering processes.
How high an NA is too high?
Authors: Prikryl Ivan
Published: February 2023

An increasing density of data stored on an optical disk requires better writing and reading control, more sophisticated data processing, and smaller laser beam stylus. An optical head can produce a smaller beam stylus by using a shorter wavelength laser diode and/or by increasing the numerical aperture (NA) of an objective lens. While the usage of a shorter wavelength is clearly curtailed by availability of short wavelength diodes, the upper limit on the NA may not be determined by constraints associated with the lens design and manufacturing. Particularly, when the recording surface of an optical disk is protected with a substrate, the upper NA limit may be dependent on disk tolerances and on the capability of a drive servo control. When the solid immersion lens (SL) technique is used, the upper NA limit depends more on the optical system design ingenuity and on the magnitude of the refractive index n of a SL lens. In the SL case the disk without substrate suffers with far less flaws. Our interest here will be in optical heads working with substrate furnished disks displaced more than one millimeter from a biaspheric objective lens.
A Preliminary Study on CD/DVD Hybrid Disc
Authors: Shin Jin-Woong , Rhee Dong-Cheol , Kim Jin-Yong , Jung Jin-Soo
Published: February 2023

Recently, DVD has been introduced into the consumer market. It is important to guarantee backward compatibility by offering CD-read capability in DVD drives. Therefore, on manufacturing DVD drives and optical pick-ups for DVD drives, it is not exceptional to evaluate those products for both DVD and CD test discs. However, using two different kinds of disc is very cumbersome and time-consuming in production line.
Near Field Recording Technology
Authors: Knight Gordon R.
Published: February 2023

TeraStor Corporation has developed a new recording system based upon Near Field Recording technology using a Solid Immersion Lens in a flying optical head. Aspects of this NFR technology will be discussed along with experimental results.
Track Count Estimator for DVD and CDROM
Authors: Graba Jim
Published: February 2023

Conventional track counting in DVD and CDROM during seek is done by operating on a combination of the sliced RF envelope and position error signal (PES) as shown in Figure 1. Although everything upstream of the slicers heretofore has been designed in analog, more is now being designed in digital hardware.
Underwater optical image enhancement based on super-resolution convolutional neural network and perceptual fusion
Authors: Liu Ke , Liang Yongquan
Published: February 2023

Underwater optical images often have serious quality degradations and distortions, which hinders the development of underwater optics and vision systems. Currently, there are two mainstream solutions: non-learning based and learning-based. Both have their advantages and disadvantages. To fully integrate the advantages of both, we propose an enhancement method based on superresolution convolutional neural network (SRCNN) and perceptual fusion. First, we introduce a weighted fusion BL estimation model with a saturation correction factor (SCF-BLs fusion), the accuracy of image prior information is improved effectively. Next, a refined underwater dark channel prior (RUDCP) is proposed, which combines guided filtering and an adaptive reverse saturation map (ARSM) to restore the image, which not only preserves edge details but also avoids the interference of artificial light. Then, the SRCNN fusion adaptive contrast enhancement is proposed to enhance the colour and contrast. Finally, to further enhance image quality, we employ efficient perceptual fusion to blend the different resulting outputs. Extensive experiments demonstrate that our method has outstanding visual results in underwater optical image dehazing, color enhancement and is artefact- and halo-free.
Effect of stacking configuration on high harmonic generation from bilayer hexagonal boron nitride
Authors: Wu Tong , Yuan Guanglu , Zhang Xiangyu , Wang Zishao , Yi Zihan , Yu Chao , Lu Ruifeng
Published: February 2023

High harmonic generation from bilayer h-BN materials with different stacking configurations is theoretically investigated by solving the extended multiband semiconductor Bloch equations in strong laser fields. We find that the harmonic intensity of AA'-stacking bilayer h-BN is one order of magnitude higher than that of AA-stacking bilayer h-BN in high energy region. The theoretical analysis shows that with broken mirror symmetry in AA'-stacking, electrons have much more opportunities to transit between each layer. The enhancement in harmonic efficiency originates from additional transition channels of the carriers. Moreover, the harmonic emission can be dynamically manipulated by controlling the carrier envelope phase of the driving laser and the enhanced harmonics can be utilized to achieve single intense attosecond pulse.
Coherence singularity and evolution of partially coherent Bessel–Gaussian vortex beams
Authors: Zhu Junan , Zhang Hao , Wang Zhuoyi , Zhao Xuechun , Lu Xingyuan , Cai Yangjian , Zhao Chengliang
Published: February 2023

For a partially coherent Bessel–Gaussian (PCBG) vortex beam, information regarding the topological charge (TC) is hidden in the phase of the cross-spectral density (CSD) function. We theoretically and experimentally confirmed that during free-space propagation, the number of coherence singularities is equal to the magnitude of the TC. In contrast to the Laguerre–Gaussian vortex beam, this quantitative relationship only holds for the case with an off-axis reference point for the PCBG vortex beam. The phase winding direction is determined by the sign of the TC. We developed a scheme for CSD phase measurement of PCBG vortex beams and verified the aforementioned quantitative relationship at different propagation distances and coherence widths. The findings of this study may be useful for optical communications.
Modulating the afterglow time of Mn2+ doped double perovskites by size tuning and its applications in dynamic information display
Authors: Wang Peng , Wang Ying , Guan Wei , Dong Hongzhou , Sui Lina , Gan Zhixing , Dong Lifeng , Yu Liyan
Published: February 2023

Mn2+ doped lead-free double perovskites are emerging afterglow materials that can avoid the usage of rare earth ions. However, the regulation of the afterglow time is still a challenge. In this work, the Mn doped Cs2Na0.2Ag0.8InCl6 crystals with afterglow emission at about 600 nm are synthesized by a solvothermal method. Then, the Mn2+ doped double perovskite crystals are crushed into different sizes. As the size decreases from 1.7 mm to 0.075 mm, the afterglow time decreases from 2070 s to 196 s. Steady-state photoluminescence (PL) spectra, time resolved PL, thermoluminescence (TL) reveal the afterglow time monotonously decreases due to the enhanced nonradiative surface trapping. The modulation on afterglow time will greatly promote their applications in various fields, such as bioimaging, sensing, encryption, and anti-counterfeiting. As a proof of concept, dynamic display of information is realized based on different afterglow times.
Does the smartphone’s eye protection mode work?
Authors: Xu Wenqian , Wu Peiyu , Yao Qi , Zhang Rongjun , Li Pengfei , Bao Leimin , Wang Cheng , Chen Shenfei , Zhang Yuhui , Shen Yedong
Published: February 2023

People spend about 5-8 hours per day on phones, causing circadian disruption and eye fatigue, thus raising a great need for comfort and health. Most phones have eye protection modes, claiming a potential eye protection effect. To examine the effectiveness, we investigated the color quality, namely gamut area and just noticeable color difference (JNCD), and circadian effect, namely equivalent melanopic lux (EML) and melanopic daylight efficacy ratio (MDER), characteristics of two smartphones: iPhone 13 and HUAWEI P30, in normal and eye protection mode. The results show that the circadian effect is inversely proportional to color quality when the iPhone 13 and HUAWEI P30 changed from normal to eye protection mode. The gamut area changed from 102.51% to 82.5% sRGB and 100.36% to 84.55% sRGB, respectively. The EML and MDER decreased by 13 and 15, and, 0.50 and 0.38, respectively, affected by the eye protection mode and screen luminance. The EML and JNCD results in different modes show that the eye protection mode benefits the nighttime circadian effect at the cost of the image quality. This study provides a way to precisely assess the image quality and circadian effect of displays and elucidates the tradeoff relationship between them.
Estimation of optical properties of turbid media using spatially resolved diffuse reflectance combined with LSTM-attention network
Authors: Sun Danni , Wang Xin , Huang Min , Zhu Qibing , Qin Jianwei
Published: February 2023

The accurate estimation of the optical properties of turbid media by using a spatially resolved (SR) technique remains a challenging task due to measurement errors in the acquired spatially resolved diffuse reflectance (SRDR) and challenges in inversion model implementation. In this study, what we believe to be a novel data-driven model based on a long short-term memory network and attention mechanism (LSTM-attention network) combined with SRDR is proposed for the accurate estimation of the optical properties of turbid media. The proposed LSTM-attention network divides the SRDR profile into multiple consecutive and partially overlaps sub-intervals by using the sliding window technique, and uses the divided sub-intervals as the input of the LSTM modules. It then introduces an attention mechanism to evaluate the output of each module automatically and form a score coefficient, finally obtaining an accurate estimation of the optical properties. The proposed LSTM-attention network is trained with Monte Carlo (MC) simulation data to overcome the difficulty in preparing training (reference) samples with known optical properties. Experimental results of the MC simulation data showed that the mean relative error (MRE) with 5.59% for the absorption coefficient [with the mean absolute error (MAE) of 0.04 cm-1, coefficient of determination (R2) of 0.9982, and root mean square error (RMSE) of 0.058 cm-1] and 1.18% for the reduced scattering coefficient (with an MAE of 0.208 cm-1, R2 of 0.9996, and RMSE of 0.237 cm-1), which were significantly better than those of the three comparative models. The SRDR profiles of 36 liquid phantoms, collected using a hyperspectral imaging system that covered a wavelength range of 530-900 nm, were used to test the performance of the proposed model further. The results showed that the LSTM-attention model achieved the best performance (with the MRE of 14.89%, MAE of 0.022 cm-1, R2 of 0.9603, and RMSE of 0.026 cm-1 for the absorption coefficient; and the MRE of 9.76%, MAE of 0.732 cm-1, R2 of 0.9701, and RMSE of 1.470 cm-1for the reduced scattering coefficient). Therefore, SRDR combined with the LSTM-attention model provides an effective method for improving the estimation accuracy of the optical properties of turbid media.
Polarization-switchable focal vortex beam by an Archimedean array
Authors: Chang Chin-Kai , Wei Chun-Hui
Published: February 2023

Focal position control of vortex beams has tremendous applications in optical field. Herein, non-classical Archimedean arrays were proposed for optical devices with bifocal length and polarization-switchable focal length. The Archimedean arrays were constructed by rotational elliptical holes in a silver film, which were followed by two one-turned Archimedean trajectories. The elliptical holes in this Archimedean array provide the freedom of polarization control for the optical performance by their rotation status. The rotation of elliptical hole can provide additional phase to affect the shape of vortex beam (converged or diverged) under the illumination of circular polarization. The geometric phase of Archimedes trajectory will also determine the focal position of vortex beam. This Archimedean array can produce a converged vortex beam at the specific focal plane according to the handedness of the incident circular polarization and geometrical arrangement of array. The Archimedean array was also demonstrated by experiment and numerical simulation for its exotic optical performance.
Procurement of Large Volume Optics by a Multinational Corporation
Authors: Deibler M.E.
Published: February 2023

A large multinational corporation with manufacturing facilities in many countries must carefully plan to ensure that components are purchased at the lowest cost and that these components can be used interchangeably at any production facility. This paper discusses the procedures used by Xerox to achieve those goals for optical components, specifically lenses.
Optics in Tucson
Authors: Anderson David S.
Published: February 2023

During the Optical Fabrication and Testing meeting in Tucson, I presented a thirty minute video-tape which took the viewers on a short tour of three independently owned optics shops located in Tucson. The participants at the meeting had an opportunity to tour first-hand the large optics shops at Kitt Peak National Observatory and at the Optical Sciences Center., The video-tape presentation was done to show that these two large shops are not the only places where optics, particularly large optics, are made in Tucson. Although the shops I visited are not the only ones in Tucson, they are the shops where much of the large optics are made.
Computer Modeling of Large-Tool Polishing
Authors: Pearson E. T.
Published: February 2023

Large optical surfaces (e.g., telescope mirrors) are often individually made to precise surface tolerances by grinding and polishing. The optician in charge chooses his tools, materials and geometry parameters, based on previous experience. As work progresses, surface tests are made to reveal the progress. Changes in the polishing approach are made as he deems necessary. The total time to achieve the desired surface (within tolerance) is often one to two years.
Resolving optical design/manufacturing hang-ups
Authors: Price William H.
Published: February 2023

When the lens designer asks of the manufacturer, "Why didn't you make my lens right?" the stock answer is often another question: "Why didn't you design something I could make? Now we all know that this is not what we would call making progress. There are a number of lens design factors - we call them rules of thumb - that, from experience, the lens designer imposes on himself, because he knows that violating them produces thunder and lightning from the shop, and thunder and lightning are not what we are trying to produce. This paper deals with some of these constraints and the trade-offs faced by the lens designer in dealing with them.
Optical Fabrication Nightmares
Authors: Voras Robert P.
Published: February 2023

Optical fabrication nightmares come in a variety of forms. They are generally caused by “toos” : too thin, too thick, too large, too small, too many, too few, etc. In practice I believe many optical fabrication problems could be eliminated – or at least minimized – if there were more communication between the designer and the process engineer, up front. However, since the purpose of this paper is to describe difficult items to fabricate and possible solutions for their fabrication, I will get off my soap-box and proceed to my assigned task.
The Foucault Test
Authors: Ruda Mitchell
Published: February 2023

The Foucault test (referred to as the knife edge or wire test) was invented by L. M. Foucault in 1858. In its most basic form only a white light point source and a knife edge are necessary to qualitatively detect small errors on an optical surface. It has been shown that under ideal conditions, errors on the surface as small as λ/600 can be detected. Thus this is one of the most sensitive yet economical tests and should always be considered as an option when one has a limited testing budget.
Angular Measurements In Optical Testing
Authors: Thomas Norman L.
Published: February 2023

The measurement of angles plays an important role in practically every discipline of optics, including prism manufacture, optical assembly and alignment. It is the purpose of this paper to review some of the angle measurement techniques and how they are used in optical testing.
A Low-Budget Cylindrical-Surface Generator
Authors: McGee James F. , Mierkowski Craig M.
Published: February 2023

A Reid surface-grinder, available in many university shops has been economically modified for the fabrication of cylindrical surfaces, either convex or concave, with radii of curvature in the 5 to 10 meter range (0.4 to 0.2 diopter). The generation of larger radii of curvature requires only a slight modification of the current apparatus.
Market Survey For Diamond-Machinable Optical Components
Authors: Friday W.
Published: February 2023

Summary not available
Reflective Replicated Components
Authors: Weissman Harold M.
Published: February 2023

There are many reasons for using thin film epoxy replicas besides significant cost savings for the individual components. These reasons are described using actual applications as examples. Substrate requirements for these applications range from a flat surface for a flat mirror, to a spherical surface for a moderately fast parabola, to an ellipsoidal surface for a highly aspheric ellipsoid. A description of the replica defects caused by surface defects in the substrate is presented. Also included is a brief description of the tooling, production lead times and cost volume relationships for these applications.
Guidelines For Preparing Optical Specifications
Authors: Olson V.
Published: February 2023

Summary not available
Inspection of High-Volume Laser-Quality Optics
Authors: Chen Gih-Horng , DeBell Gary
Published: February 2023

This paper describes inspection procedures for high-volume laser-quality optics. Problems involved with surface quality inspection and some solutions for these difficulties are discussed. Functional testing equipment utilizing laser intracavity techniques for the inspection of critical laser optics are illustrated.
Contamination Control in Aspheric Element Production
Authors: Sawyer Robert N.
Published: February 2023

Aspheric optical element production involves potential exposure to hazardous materials that include beryllium, silica and solvents. Subjects discussed include adverse health effects, contamination mechanisms and possible control methods, environmental and biologic monitoring, personnel protection, and regulatory compliance.
Hot Forging the Infrared Lens: Potassium Bromide
Authors: Schmit F. M. , Anderson R. H. , Leung K. M. , Betsch R. J.
Published: February 2023

Alkali halides can be deformed much like metals at elevated temperatures and high pressure. A novel procedure is described where a KBr single crystal is deformed, while heated to 250°C in a 4000 psi helium atmosphere, and shaped between pyrex die surfaces. The process involves two separate forging operations. The first step introduces a 60% reduction followed by a slight mechanical shaping. The second forging operation produces the finished optical surfaces of the KBr lens. To demonstrate optical performance, the KBr lens is used as the color corrector in a Forward Looking Infrared (FLIR) imager. Near difraction limited performance is demonstrated in a FLIR. Although the surface figure of the lens is complicated, transmission tests including, double pass interferometry, two wavelength holography, arid a shearing plate test all show that at 8-12µm the forged KBr will perform very acceptably.
Epoxy Replication of Aspheric Optics*
Authors: Weissman Harold M.
Published: February 2023

There are many reasons for using thin film epoxy replicas besides significant cost savings for the individual components. These reasons are described using actual applications as examples. Substrate requirements for these applications range from a flat surface for a flat mirror, to a spherical surface for a moderately fast parabola, to an ellipsoidal surface for a highly aspheric ellipsoid. A description of the replica defects caused by surface defects in the substrate is presented. Also included is a brief description of the tooling, production lead times and cost volume relationships for these applications.
An Absolute Reflectometer
Authors: Stutz Glenn E.
Published: February 2023

Optical elements need to be accurately characterized for today's specialized applications. The transmission of a lens, the reflectivity and surface roughness of mirrors are quantities that have to be determined to a high degree of accuracy for many applications. The device that is capable of performing these tests is a reflectometer.
Optical Instrumentation for Large Mirror Measurements
Authors: Archibald P. C.
Published: February 2023

Reliable performance of an individual component intended for use in an optical system can only be predicted after making one or more characterizing measurements. Some of those important measurements are figure, reflectance, and scatter. The intent of this paper is to describe instrumentation and techniques used in determining those factors for reflectors ranging in size up to 0.4 meters in diameter.
Optical Testing with the Digital Heterodyne Interferometer
Authors: Massie N. A.
Published: February 2023

In the digital heterodyne interferometer, the single frequency output of a laser is split, and each component is frequency shifted by separate Bragg cells. The difference of the frequency shifts can be 0 Hz for conventional "see the fringe" operation, or 1 MHz for accurate phase measurement. One of these components then has its polarization rotated by 90°, and the two are combined without loss by a polarization selective beam combiner cube. The composite beam is expanded to 2 cm, and injected into a polarization selective Twyman-Green interferometer. Each arm has a quarter-wave plate oriented such that the return radiation has its polarization rotated 90°, and the two beams then exit the interferometer. Thus, at the interference plane there exists light of orthogonal polarizations with one polarization having traveled the reference path and one the test path; and the polarizations have a 1 MHz frequency difference. A linear polarizer oriented at a 45° angle to these polarizations causes the beams to mix.
Chemical Durability of Optical Glass
Authors: Izumitani Tetsuro
Published: February 2023

Polished surface of optical glass has a tendency to deteriorate in the fabrication process. Typical deteriorations are dimming, staining and latent scratch. Dimming is formed due to the chemical reaction between glass and a small quantity of water such as condensed dew on glass surface. Staining is generated due to the chemical reaction between glass and relatively a large quantity of water. Soluble components are dissolved into water, and then a thin residual surface layer which has lower index than matrix glass cause interference color. And latent scratch is caused by over-all dissolution of glass surface. Tiny undetectable scratches formed in polishing process grow to detectable size as a result of surface dissolution in the ultra-sonic cleaning process.
Inclusions in Cultured Quartz Crystal — New Development and Lower Concentrations
Authors: Kinloch Durand R. , Brumbaugh James D.
Published: February 2023

Quartz crystal has long been used for its birefringence, optical activity, hardness that supports fabrication, and chemical inertness that allows optical surfaces to be stable in all but the most corrosive environments. Historically, quartz like Iceland spar has been found in ground deposits. Sections suitable for optical use representing only a small fraction of the miner's product are isolated through long hours of raw material inspection and the loss of partially finished optics in the fabrication shop.
Adjustable Aspheric Corrector and Inexpensive Aspherics
Authors: Nafarrate Antonio B.
Published: February 2023

A refractive optical component L is made as a close contacted "sandwich" of two different materials with refractive indexes n1 and n2 and has flat and parallel exterior surfaces.
Spherical Continuous Annular Polishing Machine
Authors: Nord Donald D.
Published: February 2023

In recent years, plano continuous annular polishing machines have become popular in achieving ultra-flat optical surfaces. These machines offer the advantages of achieving fractional wavelength accuracies in very short times and with minimum operator attention, as well as giving exceptionally low levels of fine structure, which in turn gives minimum scatter light -- a factor important in laser or ultraviolet light applications.
Blocking Techniques and Materials
Authors: Bickel Edward E.
Published: February 2023

Summary not available.
Manufacturing Techniques for Large-Side Ultraprecision Prism
Authors: Yin Mu
Published: February 2023

Optical contacting is usually used in the traditional machine polishing method for manufacturing precise angle prism. The defects of this method are well known; Strict technical specification and complex equipments are required. So it is hard to get high level accuracy. In general speaking, the angle accuracy is not easy with a tolerance of less than 2".
An Optical System for Precision Orientation of Frequency Conversion Array Crystals*
Authors: Johnson B. C. , Hugenberger R. E. , Marchi F. T. , Ozarski R. G. , Warshaw S. , Bradley K. R.
Published: February 2023

Livermore's Novette laser has served as a test bed facility for large aperture (74 cm) frequency conversion crystal arrays1. Crystal arrays are matrix assemblies of KDP segments sandwiched between support windows to form a monolithic structure that operates on the laser as a single optical element.
Spherical Lapping Velocities
Authors: Brown N. J. , Hed P. Paul
Published: February 2023

Today most lapping and figuring calculations are based on two dimensional rather than the true three dimensional geometry. This is equivalent to assuming the lens surfaces are planes rather than spheres. For most single surfaces (and this includes all figuring calculations) this is quite adequate since the deviations from reality are usually less than the noise or indeterminacy of pitch lap geometry. However, they are inadequate for deep spheres, deep lens blocks, and to answer questions of subtle cummulative effects.
Diamond Turning and Tools as a Process for Producing Surfaces on Aluminum for Memory Disks
Authors: Grandia Joseph
Published: February 2023

Summary not available
Infrared Phase Shifting Interferometry Using a Pyroelectric Vidicon
Authors: Koliopoulos Chris L. , Stahl H. P.
Published: February 2023

Phase-shifting interferometric phase measurement techniques are applied to pyroelectric vidicons operating at a wavelength of 10.6 microns. Special considerations are discussed in obtaining accurate wavefront measurements.
Optical Craftsmanship
Authors: Janeczko D.
Published: February 2023

During the development of a training program for opticians and optical technicians a series of World War II (circa 1944) training materials, "The Optical Craftsmanship Series" developed by the U.S. NAVY and U. S.O. E. were found.
Practical Design Consideration of Optical Machining and Tooling
Authors: Nord Donald
Published: February 2023

This paper presents approaches to optical machinery design including design concept, application, and material choice for conventional and planetary machines. Optical tooling design and materials will also be discussed.
The Error Distribution Test of Optical Wavefronts
Authors: Schmitt Paul S.
Published: February 2023

For all of the precision available using heterodyne interferometers to measure wavefronts, they still are inadequate for some finer points of lens molding development. Wavefronts can have the same root mean square optical path difference (RMS-OPD) and yet have greatly different wavefront shapes and performance. The Error Distribution Test (EDT) introduced here is a method derived from the Chi Square statistical test. It examines the distribution of spheric, comatic, astigmatic, and general residual aberration derived from the Zernike analysis performed on each of the two wavefronts to be compared. A coefficient results from comparing the two wavefronts. The coefficient is compared with an experimentally derived confidence interval. A resulting conclusion can be relative to the null hypothesis that the two wavefronts have the same distribution of errors.
Optical Null-Systems and their Application to Practical Interferometric Testing
Authors: Meckel Julius
Published: February 2023

Summary not available
Free Abrasive Grinding and Polishing
Authors: Brown N. J.
Published: February 2023

Summary not available.
The Importance of Blocking
Authors: Karow Hank H.
Published: February 2023

Blocking is a necessary process step during the manufacture of optical components. It needs to be performed at least twice and frequently more often during the manufacturing process. In most cases, blocking is taken for granted and the effect that blocking can have on the quality of the finished part is rarely considered. While much emphasis is put on controlling the grinding and polishing steps, the quality of the finished component may have been already compromised by the choice and execution of the blocking method. It is surprising that blocking is considered a secondary support task that is in most shops delegated to the less skilled workers.
A Spherical Grinding Head
Authors: Lund Lance D. , Morton Harvey L.
Published: February 2023

A prototype spherical grinding spindle has been developed for the generation of difficult aspheric surfaces. This device uses a peripheral grinding wheel rotating about two orthogonal axes to produce a spherical grinding surface which wears uniformly during the generation of an aspheric surface. Hydrostatic bearings are used for both axes and the design and performance of these bearings will be discussed. The grinding forces for numerically controlled grinding have been measured using a three axis dynamometer. The subsurface fracture depth has been characterized for both continuous and intermittent grinding operations, by polishing a generated sample at a known angle. Examination with a phase contrast microscope allows the depth of the fractures to be determined from the known angle between the generated surface and the polished surface.
Reflection-Transmission Moire Deflectometer
Authors: Glatt I. , Kafri O.
Published: February 2023

we propose an improved setup for the moire deflectometer with a built-in telescope. In the classical deflectometer a collimated beam passes first through the phase object and then projects the shadow of the first grating on a second one located at a distance Δ from the first, thus yielding a moire pattern. To analyze reflective surfaces a modified setup is used. The collimated beam is first projected on the surface at an angle ϕ. and the two gratings are placed on the course of the reflected beam. This setup suffers from an inherent distortion at one of the axes of 1 x cos ϕ. Shadowing might occur at high angles. In the new setup a Galilei telescope, like the Fizeau interferometer, is used. After recollimating by a large objective lens the beam passes through the phase object and is reflected back into the telescope, thus passing twice through the object. The retraced beam is diverted by 90° into a small objective lens and recollimated, so that a small diameter deflectometer might be used. This setup can be easily modified to measure flat specular objects simply by replacing the flat reflector by the tested object. It can also measure highly curved surfaces simply by adjusting the position of the large objective lens, so that the beam divergence after leaving the lens coincides with the radius of curvature of the surface. No additional optical element is required for these measurements. Another advantage of the new setup derives from the telescopic design. If the diameter of the beam incident on the deflectometer is reduced by a factor M, the ray deflection angle increases by the same value. So that the distance between the gratings which provides the same fringe shift is reduced. This decreases the noise due to gratings' imperfection. Moreover, the blur due to diffraction orders higher than ±1 is also reduced by a factor M.
High Speed Polish Techniques
Authors: Crook Mike
Published: February 2023

Maximizing productivity in an optics shop requires that polish cycles be minimized. Polishing involves removal of the damaged surface layer of the lens. This damage is incurred in the rough and fine grind operations preceeding polish; minimizing surface damage coming from these operations is critical. Both chemical and mechanical processes play a role in polish. While the chemical process is not completely understood and varies widely with materials, the mechanical process is relatively well understood. Its effectiveness is directly proportional to the pressure and relative velocity between the polisher and the lens. By increasing pressure and speed, the polish cycle can be shortened. However, maximum values of these parameters are limited by lens configuration, material, and hydroplaning effects that may occur at higher relative velocities. Techniques for mitigating these limitations through the use of the right equipment, tooling and processes are discussed. Additional methods for achieving productivity gains through the use of integrated cells which combine all operations into a single area, controlled by a single operator, are also discussed.
Maximum Entropy Analysis of Dynamic Light Scattering Signals
Authors: Laeri Franco , Noack André
Published: February 2023

Glass transition temperatures of thin polymer coatings (similar to the coating of a magnetic storage disc) on alumina substrates have been evaluated with dynamic light scattering methods. At this temperature the correlation time of the thermodynamical fluctuations in the polymer increases and so the spectrum of the dynamic light scattering signal changes accordingly. In practise only partial knowledge of the autocorrelation function exists, usually based on a finite series of data samples taken in a finite intervall. In the common analysis the autocorrelation function is set zero for all lags for which no estimate exists or the missing data is replaced by the already measured data of the intervall. Both procedures of course can not lead to correct autocorrelation functions or spectra. Maximum entropy methods can give the most unbiased estimates of the missing data and so lead to the "best possible" autocorrelation function/power spectra obtainable from such a limited data set.
Testing of Aspheric Surfaces with Computer Generated Holograms
Authors: Tang Yaw-Tzong , Chang Ming-Wen
Published: February 2023

Usually, aspheric testing by CGH uses Twyman-Green interferometer setup. Then the accuracy is limited by the reference mirror and optical elements been used. We use the modified Fizeau interferometer setup. A second beam splitter is placed in the focal plane of a diverger lens. The reflection beam by this B.S. is regarded as reference wave. Then the setup will have three merits: (1) The two beams go through almost the same position at each optical element, so the quality of the optical elements such as the diverger lens and the first beam splitter can be neglected. (2) The second beam splitter (now the reference surface) is easily to be made high quality because of the region been used is very small. So we may consider the reference wave as perfect. (3) It is easily to control the diffraction order to obtain the interference pattern. Besides, we describe the real interference pattern by computer based on analytic equations and calculate the exact position of the interference fringes as in the conventional hologram. Therefore, the plot of the CGH is pure interferometric type.
Calculation of Diffraction Image Quality Using Apodized Wavefront Data
Authors: Selberg Lars A.
Published: February 2023

The point spread function (PSF) of an optical system is a function of both the amplitude and phase of the electric field in the exit pupil. Interferometric testing of optics yields information regarding variations in phase, but not in amplitude. Typically the PSF, encircled energy function (EEF) and Strehl ratio are calculated from the phase information alone, implicitly assuming that the amplitude is uniform across the pupil. For incoherent, unvignetted imaging systems this assumption is generally valid. Coherent optical systems are a different case due to the Gaussian irradiance profile of lasers. The optics in such systems are non-uniformly illuminated, the amplitude function in the pupil being characterized by a Gaussian or truncated Gaussian profile. This effect of apodization is examined for aberrated and unaberrated beams. Analytic forms and numerical results are presented, as are measurements of laser diode based optical systems. In general, little effect from apodization is seen on parameters which are typically of interest (e.g., Strehl, FWHM of PSF, 80% encircled energy) except for cases of pupil irradiance decrease of greater than half from center to edge.
Computer Integrated Optical Fabrication Cells
Authors: Czajkowski Walt , Cirasuolo Jim
Published: February 2023

Computer integrated manufacturing and flexible machining cells are making big inroads in the enthusiastic revival of american industry. Improved productivity, efficiency and costs along with an increased awareness of quality and ownership are key ingredients associated with marriage and implementation of the CIM/product cell concept.
Polishing Techniques for Improved Sapphire Surface Quality
Authors: Jordan G.R. , McKechnie T.S. , Haddock B.D.
Published: February 2023

A polishing technique has been developed utilizing a series of lead laps and diamond polishing compounds yielding improved scratch/dig surface quality on 5-in (12.7-cm) diameter sapphire. The lap material and construction, as well as polishing procedure, appear to be the key elements of this successful process. Polishing was accomplished by using a separate lap for each diamond compound size. Other critical aspects of the process include using concentric draining grooves in the laps, beveling the edges on the laps and sapphire substrate, and applying a single application of diamond compound for each lap.
Design of a Monolithic Laser Spatial Filter
Authors: Hizny John J.
Published: February 2023

Details of the design and construction of a monolithic laser spatial filter, incorporating a gradient index lens element, are presented.
Automated Metrology and Fabrication System for the Advanced X-ray Astrophysics Facility Mirrors
Authors: Sarnik Andrea , Neidhart-Zimmerman Gerry
Published: February 2023

The Advanced X-ray Astrophysics Facility (AXAF) contains nested sets of Wolter Type 1 x-ray telescopes. The high resolution optical performance required, coupled with the size of the mirrors, necessitates enormous quantities of data to characterize the optics. To this end, an automated metrology and fabrication data system was developed at Hughes Danbury Optical Systems (HDOS) under contract to TRW.
Off Axis Telescope Manufacturing Design Alternative
Authors: Breidenthal Robert S. , Johnson Kris W.
Published: February 2023

Off axis telescopes have features which can provide significant benefits in manufacture, adaption to active controls and improved performance relative to concentric systems.
Single Point Diamond Turning Process Development
Authors: Miller Arthur C.
Published: February 2023

The single point diamond turning process is a careful coordination and control of many important parameters. The Optics MODIL is evaluating a next generation diamond turning machine, designated as the Nanoform 600, manufactured by Rank Taylor Hobson. This work, which is being done in the Productivity Validation Test Bed (PVTB), employs process improvement methodologies which will enable single point turning technology to routinely produce accurate optics for visible or near visible applications.
An Interferometric Method For Measurement of the Accuracy of Single Point Contouring Tools for Diamond Machining
Authors: Myler J K
Published: February 2023

The accuracy of cnc diamond machining processes in directly related to the form accuracy of the diamond cutting tools available. Consequently both diamond tool manufacturers and machining houses require methods for inspection. The accuracy of the cutting edge which is primarily generated by the intersection of a cylinder/cone with a flat, must be typically 75-150nm. Most test methods rely on observation of the final generated cutting edge via high powered microscope. Unfortunately this means that the diamond tool manufacturer cannot qualify the accuracy of the cylindrical/conical portion of the tool prior to lapping the final flat which generates the final cutting edge. Therefore errors can only be detected on a finished tool which may result in costly re-working.
Fuzzy Analysis For Fabricating Hoe In Photoresist
Authors: Chang Rong-Seng , Lin Chern Sheng , Hu C. P.
Published: February 2023

Surface relief holograms have intrinsic nonlinearity. A very important step in fuzzy analysis of HOE fabricating process is to choice parameters from procedure for making photoresist hologram. We select some parameters for the reason we can’t fix it or control it in a economic process, and some parameters for the sake of compensation.
Diamond Polishing of Silicon
Authors: Parks Robert E. , Evans Chris , Bartos Axel
Published: February 2023

Silicon is a widely used material in IR systems and electronics. Methods to rapidly produce surfaces of a specific geometry that are also free of subsurface damage lead to more cost effective manufacture of silicon products. In particular, we have been led to this study as a potential means of polishing diamond ground aspheric surfaces for IR imaging systems.
Influence of particle morphology and agglomeration on the polishing behavior of aluminum oxide powders
Authors: McClung Floyd
Published: February 2023

Surface finishes of optical materials are greatly influenced by the size and type of abrasives that are used during the grinding, lapping, and polishing steps. This paper examines the additional characteristics of particle morphology and agglomeration as factors that will influence the surface quality. Different submicron aluminum oxide polishing powders and their influence on the polishing of different optical materials and the resulting surface finishes will be examined.
A computer simulation of smoothing during computer-controlled optical polishing
Authors: Jones Robert A.
Published: February 2023

Itek has developed computer-controlled optical surfacing (CCOS) for fabricating aspheric optical surfaces. The smoothing process plays a key role in all CCOS operations. A computer simulation algorithm was created to provide information on the CCOS smoothing process. The reliability of the algorithm was confirmed with several verification cases. The effect of pertinent tool, lap and error parameters on smoothing was determined from a series of simulations. Also, the smoothing algorithm was applied to an operational case to provide real world credibility. The smoothing simulation algorithm appears accurate and useful. The parametric study results are available and the algorithm can be applied to specific cases for guidance in proper CCOS parameter selection.
Software Design for STDCE-2 Video Ronchigram Analysis System
Authors: Stultz Kevin , Stahl H.P. , Thompson Bill
Published: February 2023

The video ronchigram analysis system supports STDCE-2 a NASA space shuttle experiment designed to characterize the behavior of silicon oil in a microgravity environment. When a two centistoke oil is placed in chambers of varying size and heated it deforms. A single channel Rhonchi system has been developed to study the contour of this deformation. The data from this system is then recorded to videotape for analysis. The video ronchigram analysis system takes the videotaped images and produces maps of the oil surface.
The Center for Optics Manufacturing
Authors: Pollicove Harvey M.
Published: February 2023

Center for Optics Manufacturing (COM) development efforts have demonstrated a revolutionary computer-controlled, flexible machining center capable of deterministically microgrinding spherical optics. The achievement established a commercially significant optics manufacturing technology, called Opticam (Optics Automation and Management), which is now being commercialized and implemented by the optics industry. Further, COM's initial Opticim (Optics computer integrated manufacturing) effort demonstrated the viability of integrating optical design, engineering, manufacturing, and management activities.
Manufacturing Sciences and Technology at the Center for Optics Manufacturing
Authors: Golini Don
Published: February 2023

Much of the COM's success stems from its regional manufacturing science and technology development collaboration. The common mission of this collaboration is to gain a complete understanding of the science of optical finishing and the manufacture of high precision optical components. The manufacturing sciences program extends successful existing programs, tapping into the expertise of some of the finest research institutions in the country. The COM is leveraging the many years of experience and expertise of the premier researchers in the field of precision machining, materials science, and optics manufacturing in the United States. The work encompasses a wide range of technical areas, and is focused on the exploration of the complex interactions between feeds, speeds, tool properties, environmental conditions, and machine characteristics for a wide range of brittle materials. To take full advantage of a CIM environment, an expansive database must be generated to enable real time rule based process control for the next generation of less expensive, more efficient machine tools.
Experience with the rapidly renewable lap
Authors: Evans C. J. , Parks R. E. , Roderick D. J. , Evans B. A.
Published: February 2023

A recent paper1 introduced the concept of the rapidly renewable lap2 and presented some preliminary results. Since then, the additional experience to be described in this presentation indicates that this lap design has advantages both for basic research into polishing mechanisms and in practical application.
Balancing cost with completeness: Specifying optics for the National Ignition Facility
Authors: Aikens D. M. , English R. E.
Published: February 2023

During the second half of the 1990's, the fabrication technologies used to make large, precision glass optics will continue to undergo profound changes, motivated by increased accuracy in metrology, increased requirements of precision, and decreasing production costs. Livermore intends to continue to benefit from these advances in its construction of the National Ignition Facility. In order to do so cost effectively, however, it is necessary to generate specifications which balance the requirements for precision with the desire to contain costs. Key to this is to specify as precisely and simply as possible what is required, balanced with the minimum necessary metrology and certification.