bluuebunny/crossref_metadata_2025 huggingface dataset:
Employment law SOS
Authors: Beswick David
Published: February 2023

This month, our employment law specialist investigates a grievance over the amount of work done by an intern on work experience, returning to work after an injury against the company’s wishes, and a reduction in holiday pay
The Simulation of Combustion Characteristics from Diesel Fuel and Biodiesel in Different Engine Rotation
Authors: Bhikuning Annisa , Irhashi Zidni Rizki , Aldebaran Daniel
Published: February 2023

The combustion characteristics of fuel are important to understand. Diesel engines can ruin by using fuel from diesel and biodiesel. The characteristics between biodiesel and diesel fuel are different. Diesel fuel has low viscosity, high volatility, low density, and cetane number is around 48. However, biodiesel has high density, low volatile, high viscosity and has higher cetane number than diesel fuel. Using biodiesel can reduce the particulate matter from the engine. This happened because biodiesel has high oxygen content and can reduce emissions. These are some advantages of using biodiesel in diesel engines. In this research, the simulation of the combustion characteristics were investigated by diesel-rk simulation. The fuels are diesel fuel and biodiesel made from soybean methyl ester (SME). In this simulation, pure diesel fuel (DF), SME100, SME20 (20%SME blends to 80%DF) and SME40 (40%SME blends to 60%DF) are investigated. The combustion was set up with 1500, 1800, and 2000 rpm. The results show that in all engine rotations, DF has higher Specific Fuel Consumption (SFC) than SME. Moreover, the NO2 emission from DF is lower than SME. However, the particulate matter in SME40 can reduce up to 16.1% compared to DF. Moreover, the higher the engine rotates, the emissions from NO2 and PM from SME20, SME40, and DF can be reduced. It can be confirmed that the higher rotation in the engine can decrease the emissions in the engine.  In addition, biodiesel can be replaced with diesel fuel and it is environmentally friendly.
Land Use Prediction Using Markov – Cellular Automata in the Peusangan Watershed, Aceh
Authors: Fitri Rini , Damayanti Astrid , Simangunsong Nur Intan , , Munawir
Published: February 2023

The population growth rate is a factor that causes changes in land use that impact land ecology due to increased population activities related to social, economic, and cultural aspects. Land use change aims to develop facilities and infrastructure to meet the population's needs. This research seeks to interpret land-use changes in 1999, 2008, and 2019 and predict land use in the Peusangan watershed in 2030. The map overlay method analyzes land use change in 1999-2008, 2008-2019, and 2019-2030. In predicting land use, this study uses the Cellular Automata approach. The results of the analysis specifically show that the trend of land use change until 2030 is a decrease in the area of forest land use covering an area of 11,014 ha (4.27%), open land covering an area of 31 ha (0.01%), shrubs 6,083 ha (2.36%), and water bodies covering an area of 459 ha (0.18%). On the other hand, it is predicted that in 2030 the Peusangan watershed will see the most significant increase in land use for plantations of 14,225 ha (5.52%), followed by land use of 1,664 ha (0.65%), 817 ha (0.32%), settlements covering 710 ha (0.28%), 132 ha of rice fields (0.05%), and 28 ha of pond land use (0.01%). The results of this study are expected to be input for policymakers regarding land use planning in the Peusangan watershed in the future
The policy process of adopting environmental standards for coal plants in India: accommodating transnational politics in the Multiple Streams Framework
Authors: Turaga Rama Mohana R. , Mittal Harsh
Published: February 2023

This article provides an important international empirical application of the multiple-streams framework with some theoretical additions that make a novel contribution to the existing scholarship in this field. Using a modified multiple-streams approach (MSA) that extends Kingdon’s original agenda setting model to the decision-making stage, we analyse and explain an empirical puzzle in the context of the environmental regulation of coal-fired power plants, considered central to India’s economic development. The puzzle involves both the content – a stringency comparable to those in more developed economies – and the timing – within a year of a new national government coming to power with the promise of reviving economic growth. Our findings show how a top bureaucrat exploited the agenda window opening in the problem stream to couple the three streams, resulting in the notification of draft environmental standards. The political entrepreneurship of the same bureaucrat led to the adoption of final standards in the same form as the draft in the decision window created by developments during the period leading to the Paris climate summit. The operationalisation of the modified MSA to our empirical case generated new theoretical insights. First, we expand on the original formulation of decision stage dynamics and argue that the decision window could also open due to independent activity in any of the three streams. Second, we argue that transnational politics could act as an additional factor in the ripening of the political stream at the decision stage.
Comerç del llibre a Catalunya (2020-2022)
Authors: Bejarano Ródenas Joaquim
Published: February 2023

Es presenta el panorama del sector del llibre a Catalunya d’aquests anys marcats per la covid-19 (2020-2022): el comerç de les editorials catalanes a Espanya, la venda de llibres a Catalunya, l’exportació de les editorials catalanes al món, les tendències del sector, les llibreries i les fires.
La ética de la automatización en vehículos y enfoques alternos para problemas morales actuales
Authors: Teixidó Durán Óscar Frederic
Published: February 2023

En el presente trabajo se utiliza el problema ético de la automatización en transportes y vehículos dotados de inteligencia artificial (IA) para un análisis crítico de las diferentes posiciones éticas y morales clásicas. Debido a la intersección de la IA con los campos de investigación de la bioética, la nomoética y la tecnoética, existe un hilo conductor en sus fundamentos. Además, se juzga necesario para este propósito, así como por rigurosidad, hacer uso de una cantidad mínima de herramientas formales y exponer un proyecto de una teoría ética actualizada, sistémica y materialista, que sobrepase a sus sistemas rivales. Así, se pretende ofrecer las bases para una teoría alterna más fecunda y explicar cómo las posiciones éticas tradicionales pueden ser obsoletas, si no directamente inaplicables, para afrontar la automatización inteligente y problemas morales similares, en la actualidad.
Reconstruction algorithm using 2N+1 raw images for structured illumination microscopy
Authors: Fang Xiang , Wen Kai , An Sha , Zheng Juanjuan , Li Jianlang , Zalevsky Zeev , Gao Peng
Published: February 2023

This paper presents a structured illumination microscopy (SIM) reconstruction algorithm that allows the reconstruction of super-resolved images with 2N + 1 raw intensity images, with N being the number of structured illumination directions used. The intensity images are recorded after using a 2D grating for the projection fringe and a spatial light modulator to select two orthogonal fringe orientations and perform phase shifting. Super-resolution images can be reconstructed from the five intensity images, enhancing the imaging speed and reducing the photobleaching by 17%, compared to conventional two-direction and three-step phase-shifting SIM. We believe the proposed technique will be further developed and widely applied in many fields.
Design and Fabrication of Efficient Fiber Microlenses
Authors: Presby Herman M.
Published: February 2023

Microlenses, fabricated directly on the ends of optical fiber, are used to improve the coupling of light from semiconductor lasers into the fiber. They achieve this by matching the very much smaller mode of the laser to that of the fiber.
Binary Optic Beam Steering Techniques
Authors: Farn Michael W.
Published: February 2023

The steering of a collimated laser beam is a fundamental building block for many optical systems. Common examples include bar code scanners, laser radars, laser machining applications and laser printers.
Multi-Beam Grating Structures
Authors: Kathman A. D. , Johnson E. G. , Scott M. L.
Published: February 2023

New systems are being developed around innovative diffractive optical components. Applications in optical interconnects, signal switching and interferometry have created a need for two-dimensional optical fanout gratings with unusual geometries. The increasingly complex gratings being designed for such optical fanout devices require specialized optimization algorithms to achieve desired performance. In this paper, we demonstrate optimization of a fanout grating in an n-dimensional solution space using a simulated annealing algorithm. The algorithm provides a successful first-order design which is further optimized using wave optics design software. A three beam grating is fabricated and tested; diffraction efficiencies will be reported. By means of the example below, we present a design algorithm for fanout grating of arbitrary geometry.
Design of Diffractive Optical Elements with Rigorous Diffraction Theory
Authors: Sidick Erkin , Knoesen André
Published: February 2023

Diffractive optical elements (DOE's), such as array generators1 and coherent laser combiners,are designed with scalar diffraction theory (SDT).
A holographic focusing doublet for polychromatic sources
Authors: Aharoni A. , Goodman J.W. , Amitai Y.
Published: February 2023

We present and analyze a diffractive system for focusing polychromatic sources to near-diffraction-limited 1/e2 spot widths.
Frequency Control, Modulation, and Packaging of an SDL (100 mW) Laser Diode for a Free-Space Photonic Switching Fabric
Authors: Sasian Jose M. , Morrison Rick L. , Cloonan Thomas J. , Beckman Martin G. , Wojcik Michael J. , Hinterlong Stephen J.
Published: February 2023

Free-space optical switching and computing systems utilize macroscopic optical elements such as diode lasers, holograms, gratings, lenses, and mirrors as their basic hardware building blocks.
Design and fabrication of astigmatic GRIN elements for laser diode collimation
Authors: Brenner K.-H. , Sinzinger S. , Spick T. , Testorf M.
Published: February 2023

Due to advances in semiconductor technology laser diodes found access to more and more applications in hi-tech as well as every day products.
Complexities of image formation through liquid crystal televisions
Authors: Pezzaniti J. Larry , Chipman Russell A.
Published: February 2023

Image formation through spatial light modulators and liquid crystals is not particularly well characterized by the point spread function (PSF) and modulation transfer function of Fourier optics, although these are a suitable first approximation.
The Status and Future of High Density Magnetic Data Storage
Authors: Hoagland A. S.
Published: February 2023

Magnetic recording is entering yet another phase of explosive growth both in applications and in technology. Witness the 35mm magnetic camera and the excitement created by the rediscovery of vertical recording. Alternate technologies hoping to profit from its supposed demise (e.g; optical storage) again see their emergence threatened. This paper addresses the prospects for the "moving target" - magnetic recording.
Development of Optical Recording Disk and Devices
Authors: Unno Yoichi , Goto Kenya
Published: February 2023

Digital Optical recording is a rapidly growing technique. It needs a sensitive, long-life recording medium for the optical disks and a high power semiconductor laser installed in a read and write head. Because the sensitive layer of the disk and a focused laser beam enable widespread mass storage of digital data or documents by melting holes of about 0.7μm diam on the layer with the laser. The development of a highly sensitive and long-term stable recording medium and a high power laser diode with good optical quality are currently the subject of a great deal of interest.
A 100,000 Gigabyte On-Line Storage System
Authors: Friedlander Marc A.
Published: February 2023

We report a new optical storage technology (patent pending), and Its applications, which can provide 100,000 gigabytes of on-line storage with nanosecond read and write times, nanosecond access times, and in a volume of one cubic foot. The high storage density, and consequent short access time, is accomplished by three dimensional storage within an unstructured bulk storage medium at a storage density of one cubic micron per bit using visible light. The storage is effected by the photon echo phenomenon which decisively surmounts the problems faced by previous volumetric optical storage approaches. End user cost for production versions will be $100,000 (or 10-8 cents per bit). The Navy is examining the development of a prototype for application to tactical air reconnaissance. The prototype will allow tactical reconnaissance imagery to be received, processed and analyzed in real time as an aid to command decision making. Ground based versions could be applied to the development of large, fully relational data bases due to the presence of Inherent logic elements associated with each bit of the storage system. Highly parallel Input and output capablity as well as the ability to store analog data make it feasible to use the system as an efficient interface point between analog and digital optical information processing systems.
Ageing Characteristics of DOR Media
Authors: Huijser A. , Jacobs B. , Vriens L. , Markvoort J. , Spruijt A. , Vromans P.
Published: February 2023

Accelerated ageing tests on discs with Te-alloys for ablative optical recording show that these media meet the requirements for long-term data storage.
New Media Development at Burroughs: Material and Coating
Authors: Chao Shiuh , Bell Irving , Lee Neville
Published: February 2023

This paper is directed to one of the various optical media investigations currently being conducted by Burroughs. For this particular investigation, a conventional "trilayer" structure is employed with a thin film metal absorber layer which can be controlled in such a way that the structure is easily changed by low power laser heating. The optical transition of this metal film occurs at a temperature well below its bulk melting point. Judged from threshold recording power and change in reflectivity, the media has a sensitivity which is much better than Te. This optical transition is further enhanced by using an organic film for a spacer layer. Our media also has a high sensitivity with 7 mil overcoat.
System for Dynamic Testing of Optical Storage Media Pit Formation
Authors: Barnes Ronald L.
Published: February 2023

When working with optical storage material, the large field of data poses two problems: 1) writing the hole or pit with a singular set of controlled parameters; and 2) correlating this pit to the analysis system. The pit formation and analysis need to be simultaneous or nearly real-time. The intent of this apparatus was to bring together a large variety of adjustable parameters and the ability to analyze them such that, as the pits are formed, we can evaluate the results and immediately compensate the pit formation system in order to optimize or evaluate a given media. The system was assembled using a large multi-port testbed.
Alignment Effects in a Single Path Optical Recording System
Authors: Webb Steven L.
Published: February 2023

The light path of the system that was modeled is shown in Figure 1. The system consists of; (1) a laser pen that produces a uniform beam of collimated light, (2) a turning mirror to point the beam in the correct direction, (3) a rhombic polarizing beamsplitter to separate the incoming and outgoing beam and to set the proper laser orientation, (4) a quarter waveplate to reverse the direction of polarization between the incoming and outgoing beam, (5) an objective lens to focus the light onto the disk, (6) a servo system to move the objective lens, (7) a pregrooved disk that introduces the tracking signal, (8) a toric lens to develop the astigmatic focusing signal, (9) and a quad detector to read the focus, tracking, and data signals. The optical system is contained in a carriage which can move radially along the disk to access different areas of the disk.
Aging characteristics of amorphous magneto-optical recording media.
Authors: Jacobs B. , Braat J. , Hartmann M.
Published: February 2023

Amorphous rare-earth-transition-metal (RE-TM) materials are promising candidates for erasable optical recording. Recording, reading and erasing can be performed over 106 times without any measurable degradation. Long term stability for recording, retrieval and erasing is still a matter of concern since lifetimes are required of at least 5-10 years for these types of media.
Determination of Magneto Optical Constants from Multilayer Film Structures
Authors: Sprokel G. J.
Published: February 2023

A matrix relation is derived for the incident, reflected and transmitted wave vectors for a multilayer stack containing a magneto optic layer. The principle of the method is discussed in many textbooks. However, the dielectric function of a magneto optic medium is a 4th order equation and the resulting matrix is a complex 4 × 4 matrix. Here, the matrix is formulated without approximations and its properties are evaluated numerically.
An Overview of 7640 Storage Technology*
Authors: Stahl K. John
Published: February 2023

This presentation addresses many hardware aspects of the Storage Technology 7640 Optical Storage Unit, concentrating on Mechanics, Optics, Servomechanics, and Read/Write characteristics.
A Draw Disc Compatible with Laservision Standard Players
Authors: Wilkinson Richard , Winslow John
Published: February 2023

At present, pre-recorded optical videodiscs and disc players are manufactured to the standard of the Laservision Association to assure mutual compatibility. This disc-player system with its video capability, large storage capacity, short access time and standardized players could be used for film editing, video program assembly and document storage if discs could be recorded by the user and immediately played back on standard players.
New Ideas for Phase-Change Media - Achieving Sub-Microsecond Erase with Data Stability
Authors: Chen M. , Rubin K.A. , Barton R.W.
Published: February 2023

Reversible optical information storage based on the amorphous-crystalline phase transformation has been the subject of many investigations since the early 1970’s1-8. One of the unresolved problems associated with phase-change recording media has been the need to trade off erase (crystallization) speed against data (amorphous phase) stability. For the most part, the search for viable phase-change recording material has been based on one common approach. Starting with a group VA or VIA element in the periodic table, Te being the most popular one, attempts were made to achieve the desired properties through alloying. To date, no one has published achieving a sub-microsecond erase speed along with a practical data retention period.
Composite Prewobbling Optical Disk Memory
Authors: Yonezawa Seiji
Published: February 2023

The prewobbling preformated disk drive realize a highly optical stability and an accurate track following which is not influenced by optical head characteristics. Two possible types of prewobbling disk for 5 1/4 inches have been studied.
Standardization Activities for Optical Disks in Japan
Authors: Mitsuhashi Yoshinobu
Published: February 2023

In the optoelecrronic industry, optical disks are considered one of the most promising technologies following optical communication. In recent years, technical development of the optical disk has been startling, with the marketing of the video disk (VD) and the digital audio disk (CD) followed by the document file and the code data disks, all of which illustrate its increasing variety. The international standards for VD and CD have been almost completed by the IEC / TC 60 (International Electrotechnical Commission, Technical Committee 60A: Sound Recording, 60B : Video Recording).1) International standardization of Optical Digital Data Disks (OD3) is being achieved by the activities in the ISO / TC 97 / SC 23 (International Organization for Standardization, Technical Committee 97 : Information Processing Systems, Sub-Committee 23: OD3).2)
Magneto-Optical Properties of Amorphous Magnetic Thin Films
Authors: Uchiyama Susumu
Published: February 2023

Tb-Fe amorphous films were found to be very promising materials for magneto-optical recording1), since they have (1) a large perpendicular magnetic anisotropy which ensures a recording density as high as 109 bits/cm2, (2) a Curie point TC of about 140°C which is reasonable from the view points of high thermal stability of written bits and of low laser power for Curie point writing, and (3) a very low medium noise due to the amorphous state. These films, however, have a magneto-optical Kerr rotation θk of only 0.25 degrees at room temperature, which is smaller than that for Gd-Fe and Gd-Co films. Therefore, many efforts have been made in Japan in order to increase θk of Tb-Fe films. Good results are obtained by replacing a part of Tb and/or Fe by Gd and/or Co. The maximum θk found so far is about 0.5 deg for quaternary films with a composition around (Gd0.5Td0.5)0.2(Fe0.7Co0.3)0.8, where θk is measured from the sub-strate (glass) side using light of λ=633 nm wave length.
Improvements in Corrosion Resistance of Tb-Fe Thin Films
Authors: Kobayashi M. , Asano M. , Kawamura K. , Ohno S.
Published: February 2023

Amorphous rare earth-transition metal thin films (RE-TM films) have properties suited for erasable optical memory media. They have been widely studied and will be soon in a step of practical use. These films, however, have the drawback of poor reliability due to their poor corrosion resistance. We have reported that the corrosion of the films is classified as being the surface oxidation, the selective oxidation of RE metals, and electrochemical corrosion.1,2 To protect the RE-TM films from the corrosion, two methods can be considered. One method is to improve the corrosion resistance of the films themselves. The other is to coat the films with protective layers such as SiO, AIN.3 We have studied the electrochemical corrosion of RE–TM films immersed in a NaCl aqueous solution and succeeded in improving the corrosion resistance of the films themselves by adding several metals.
Application Interface of WORM Optical Drives
Authors: Dulude J. R.
Published: February 2023

The design goals of the application interface of the 5984 Optotech 5.25 inch optical disk drive are quite simple: modularize components to hit the broadest market base possible; and put as much of the burden of integration on Optotech -- thus speeding applications from development to marketplace. To accomplish these goals, several hardware and software interfaces had to be designed.
Theoretical Modeling and Experimental Characterization of Drexon Recording Media
Authors: LaBudde Edward V. , LaBudde Robert A. , Hazel Robert
Published: February 2023

Drexon recording media consists of a thin layer of silver particles on the surface of a gel substrate. A protective overcoat of laminated plastic is in contact with the recording surface. The thin layer acts as reflector and absorber of the incident light. Light transmitted through the thin film is absorbed by small particles suspended in the gel.
Erasable Optical Recording Technologies
Authors: Jipson Victor B.
Published: February 2023

The wide spread acceptance of optical recording technology in the consumer market place has provided the technological base for the development of erasable digital optical storage devices. Magneto-optic, phase change and dye polymer materials are being actively pursued for the short term, and longer range approaches based on photo-chemical hole-burning and holographic techniques are still areas of basic research. This talk will compare these various approaches with respects to the advantages and disadvantages that accompany each.
The New Application of MCAV Method to the Optical Disk Memory
Authors: Ishihara Atsushi , Yoshimaru Tomohisa , Chikamori Akino
Published: February 2023

Thus far CAV (Constant Angular Velocity) method or CLV (Constant Linear Velocity) method has been adopted as optical disk recording method.
Software Transparency and Write Once Optical Disk Drives
Authors: Dulude Jeffrey R.
Published: February 2023

This paper discusses the three levels of software transparency achievable with write once optical disk drives. First, the unusual nature of write once optical drives is addressed to demonstrate why software is needed that is different than software used with magnetic disk drives. This is followed by a framework for viewing different solutions to write-once software issues. Finally, this framework is used to examine the three levels of software transparency achievable with write-once drives.
Magneto-Optic Recording with a Compact Optical Head
Authors: Sander Ingolf , Slovenkai Stephen
Published: February 2023

An erasable magneto-optical disk drive system employing polar Kerr effect readout has been developed within the 3.5 inch half-height form factor (41x101x146mm). The drive exhibits rapid seek times and data transfer rates greater than 1 Mbit/sec. The disk is contained in a cartridge and has a formatted user capacity greater than 50 MBytes. The system is ideal for the personal computer marketplace, giving the performance of a Winchester drive, the portability of a microfloppy and the advantages of optical recording.
The Rigid Optical Disk Assembly by Eastman Kodak Company
Authors: Maher James
Published: February 2023

The Kodak write once optical media consists of a dye/binder, gold reflector bilayer structure on a 14" aluminum support. Excellent performance and aging characteristics have been demonstrated on pilot line production media.
Test System for Measuring Mechanical and Recording Characteristics of Optical Disks
Authors: Yamamoto Masato , Mikuriya Kenta , Sato Masahiro , Hanawaka Masuo , Ohya Akira
Published: February 2023

We have developed two test systems for measuring, respectively, the mechanical and optical (recording) characteristics of optical disks. The mechanical characteristics test system measures axial and radial runout, etc. It has optical displacement sensors with accuracy of 0.1 um in the axial direction and 0.01 um in the radial direction. The optical (recording) characteristics test system measures reflectivity, CNR, error rate, defects, etc. The system has a SNR of better than 70 dB.
Digital Optical Recording - The Case for Coding
Authors: Howe D. G. , Meichle M. E.
Published: February 2023

The use of run-length-limited modulation codes to increase the storage capacity and data transfer rate of digital optical recorders is discussed.
Optical and Thermal Analysis of Erasable Optical Storage
Authors: Zhou Zhiping , Chin Kuofan , Wang Minqiang
Published: February 2023

In erasable optical storage, the requirements for writing, read and erasure processes to the distribution of the optical field and the time-space distribution of the temperature field induced by pulse laser are harsher than those in nonerasable optical storage. So, it is highly necessary to consider about parameters in optics, thermology and structure, latent heat effect (phase-change model), magneto-optic Kerr and Faraday effects (magneto-optic model), etc. more carefully and all-sidedly in designing the distributions of optical field and heat field.
The Dependence of Maximum Readout Power on Various Properties of Thin-Film Magneto-optic Media
Authors: Stinson D. G. , Petronio J.
Published: February 2023

In magneto-optic recording it is desirable that the read laser power be as large as possible without causing degradation of the recorded information. We have developed a test that efficiently simulates the repeated reading of the recorded magnetic domains. This technique is used to determine the maximum read power and minimum write power of a variety of magneto-optic materials on a variety of substrates. In this paper we report the correlation between maximum read power and the sample’s coercivity and substrate.
Practical Specifications for Characterizing Write/Read Performance of Optical Disk Media
Authors: Lange Gerald R.
Published: February 2023

The measurement of write/read characteristics of the media is a common requirement of all media manufacturers. This paper describes the methods used at Eastman Kodak Company in the characterization of the 14" write once media.
High Storage Density Optical Disks using Pit Edge Recording on Pb-Te-Se Thin Film
Authors: Saito Atsushi , Maeda Takeshi , Sugiyama Hisataka , Tsunoda Yoshito
Published: February 2023

Optical disk file is suitable for high density recording, read-only and write-once type are on the market. For write-once type optical disk, higher data transfer rate and higher density recording are required for the future development. Present write-once optical disk uses the recording method of making a circular pit corresponding to coded-data ”1”. On the other hand, pit-edge recording, namely, the leading or trailing edge of a pit corresponding to coded-data ”1”, can achieve about twice higher BPI (bit-per-inch) than that of the former method. Up to the present, the ablative recording media have been thought to be difficult to apply this pit-edge recording because of their uncontrollabi1ity of pit shapes. However, this problem can be solved by introducing a new compensation technique during writing and reading the data.
Recording Results and Coding Considerations for the Resonant Bias Coil Overwrite Technique
Authors: Rugar D. , Siegel P.
Published: February 2023

Magneto-optical recording using field modulation has been shown previously to be an effective method for achieving direct overwrite.1,2 One disadvantage of this technique, however, is that high data rate operation requires the coil diameter and coil-to-media spacing to be small. This limitation is a result of the stored magnetic field energy which must be refreshed each time the field is reversed. The resonant bias coil overwrite technique, which was introduced recently,3 largely overcomes this problem and allows high frequency operation with coil-to-media spacings on the order of 1 mm. This paper presents recent recording results using this technique and discusses some data coding implications.
Compact magneto-optical disk head using reflection polarizing holographic optical element
Authors: Ohba Akitomo , Kimura Yasuo , Sugama Seizin , Katayama Ryuichi , Okada Mitsuya , Ono Yuzo , Nishida Nobuo
Published: February 2023

In an optical data storage system, a small-size and light weight optical head is required for high speed track access. A holographic optical element(HOE), which can be combined with focusing error detecting function, tracking error detecting function and beam splitting function, has high potential to realize a small size optical head1). To enable applying the HOE for a magneto-optical(MO) head, it is required that the HOE possesses polarizing characteristics in the HOE's beam splitting function2). For this requirement the authors have developed an MO head using reflection polarizing HOE(R-PHOE). This paper describes the design for the R-PHOE, optical head configuration, fabrication of the R-PHOE and head operation characteristics.
Development of a New Optical Head for Magneto-optic Library Units
Authors: Moritsugu Masaharu , Arai Shigeru , Futamata Akio , Abe Fumitake , Ogawa Kouichi
Published: February 2023

Optical disk systems are expected to meet the demands of large memory capacity because their recording density is about ten times higher than that of magnetic disks or tapes. A mass storage library system already implemented for a jukebox system. It used write-once optical disks and had a long access time. Recent advances in optical disk technology have increased the demand for erasable disks. Faster access times for mass storage systems are needed.
Manifestations of Through Thickness Thermal Gradients in Laser Irradiated Thin Films
Authors: Bartholomeusz Brian Josef
Published: February 2023

Low conductivity, laser-irradiated thin films such as the chalcogenides employed for optical data storage can display manifestations of significant through-thickness thermal gradients. These gradients appeared to be strongly influenced by the laser incidence direction, the coefficient of optical absorption, and the film thickness, and influenced to a lesser degree by the scanning velocity.
Highly Reliable 7GB, 1.2-2.2MB/S Twelve inch Write Once Optical Disk
Authors: Watanabe H. , Koyama E. , Nunomura T. , Taii T. , Iida T. , Miura M. , Gotoh A. , Nishida T. , Horigome S. , Ohta N.
Published: February 2023

12" W-O type optical disks are used for large capacity archival data storage system. To extend application area more widely both larger data capacity and higher data transfer rate are required. Such a high density disk also requires more advanced reliability and durability. This paper describes double sided 7GB twelve inch diameter disk for high data rate (1.2-2.2MB/s) application keeping disk life longer than 45 years. User data capacity is advanced using pit-edge method1) and MCAV(Modified Constant Angular velocity) method. Corrosion resistant Te alloy recording layer has high signal to noise ratio, and wide jitter margin. High rotation speed makes data transfer rate higher. Acceleration test shows high reliability.
Cystalization Kinetics in Ge2 Sb2 Te5 Phase-change Recording Films
Authors: Ozawa Kenji , Ogino Shinji , Satoh Yoshikazu , Urushidani Tatuo , Ueda Atushi , Kawakami Haruo
Published: February 2023

Amorphous bit marked in active layer of phase-change optical disk must be crystalized in very short time and be stable at room temperature. We have made clear the crystalization mechanism of Ge2Sb2Te5, which was well known as phase-change recording material, through the isothermal anneal tests and observation of the crystalization behavior of recorded bit by transmission electron micrograph. (VTR-TEM)
3-Beam Overwritable Magneto-Optic Disk Drive
Authors: Watabe Akinori , Yamada Ichiro , Yamamoto Manabu , Katoh Kikuji
Published: February 2023

First generation magneto-optic (MO) disks have been on the commercial stage advancing their standardizations. To introduce the next generation, development activities are focused on overwritable optical disk technologies such as magnetic modulation or the use of multilayer recording material.1)
Focus-error Detection from Far-field Image Flow
Authors: Ishibashi H. , Tanaka S. , Moriya M.
Published: February 2023

It becomes more necessary to produce optical heads in small size, in low weight and in low cost. For that purpose, we think that the optical heads would rather be simplified than be integrated. Furthermore, the optical heads should be manufactured without accurate adjustment if possible.
Lissajous Analysis of Focus Crosstalk in Optical Disk Systems
Authors: Grove Steven L. , Getreuer Kurt W. , Schell David L.
Published: February 2023

In many optical disk systems, diffraction from a pregrooved disk produces a "push-pull" pattern in the reflected beam which is used to generate the tracking error signal (TES). In some cases, effects of the pregroove diffraction also show up in the focus error signal (FES), resulting in an unwanted variation of the FES. This phenomenon is known as focus crosstalk.
Development of High Performance 86mm MO Disk by Using Polycarbonate Substrate
Authors: Ito Katsunori , Shibata Yasumasa , Honda Katsunori , Tsukahara Makoto , Kojima Kotaro , Kimura Masakatsu , Fujisima Toshihiko , Yoshinaga Kazuomi , Kanai Toshitaka , Shimizu Keijiro
Published: February 2023

We have developed a 86mm MO disk on the basis of 3-D thermal analysis of the disk mold and optimization of the protective layer. This disk shows excellent initial characteristics and reliability. This indicates we can manufacture high performance disks by using polycarbonate substrate.
On Interchangeability of Optical Disk
Authors: Shimamoto Masayoshi , Yamada Koichi , Watanabe Isao , Nakajima Yoshiki , Itoh Osamu , Tanaka Kunimaro
Published: February 2023

As image data has been widely used, the demand for large capacity exchangeable recording media has been increased. Among various exchangeable recording media optical disk is promising for its small size and fast access speed.
Status and Challenges of Waveguide Blue Lasers
Authors: Risk W. P.
Published: February 2023

The advantages of short-wavelength lasers for magneto-optic recording have long been recognized. Recording at ~1 Gbit/in2 was demonstrated several years ago using an Argon-ion laser at 488 nm [1]. More recently, recording at 2.4 Gbit/in2 has been demonstrated using a 488-nm Argon-ion laser and a frequency-doubled GaAlAs laser diode at 429 nm [2]. However, both Argon-ion lasers and frequency-doubled diode lasers are relatively bulky and expensive compared to the infrared diode lasers used in commercial magneto-optic recording systems. Hence, a great deal of research continues to focus on the development of small, efficient, low-cost blue sources with powers suitable for optical recording. Although the advent of blue-green semiconductor laser diodes based on II-VI materials has attracted much attention, sustained, reliable room-temperature operation at powers suitable for recording applications has not been demonstrated, and a recent study of defect formation in such lasers suggests that development of a source suitable for recording applications may be very difficult [3].
Ultra High Density Data Storage by Atomic Manipulation
Authors: Imura Ryo , Koyanagi Hajime , Miyamoto Mitsuhide , Shintani Toshimichi , Nakamura Kimio , Kikukawa Atsushi , Hosaka Sumio
Published: February 2023

Nanometer and atomic scale surface modification using scanning probe microscopes is a new and promising method to store data with ultra high densities [1]-[3]. It is expected that this technique has the potential to achieve a storage density of more than 100 Gb/in2 and even 1 Tb/in2. Advances in storage techniques using several local probe methods such as tunneling, force and near-field optical microscopes have been reported recently. One of the most simple way is to form ultra small pits or dots on a substrate by means of field evaporation of tip surface atoms. Another method is related to the switching phenomena similar to conventional magneto-optical disk memories and by using a sharp tip to heat a point area of the storage medium.
High Density Holographic Storage in Thin Films
Authors: Curtis Kevin , Pu Allen , Psaltis Demetri
Published: February 2023

Volume holographic architectures in the form of rotating disks [1] or stationary volumes [2] have been demonstrated for data storage. Recently, thin film materials have been developed that are inexpensive, easy to manufacture, can be applied to large glass substrates, and have relativily large dynamic range. An example of such a material is DuPont’s HRF-150 photopolymer [3,4]. A holographic storage system’s density is limited by two parameters – the system’s bandwidth (either temporal or spatial frequency) and the material’s dynamic range. Because of their relativily large dynamic range and limited thickness, the storage density of thin films is limited primarily by the required system bandwidth. This paper describes a method of multiplexing holograms that alleviates the bandwidth limited density problem, and therefore, significantly increases the storage density of thin films.
A Real-time, High Resolution, PC-based System for Measurement of Errors on Compact Discs
Authors: Tehranchi Babak
Published: February 2023

The new writable Compact Discs (CDs), such as the CD-R and Kodak's PhotoCD, are physically different from pressed CDs (such as CD-ROMs and Digital Audio Discs) and data marks are written on them with an entirely different physical process. Therefore, it is possible that the nature and statistical characteristics of errors that contaminate data carried by writable and pressed CDs will be quite different. This subject is addressed in an invited talk that is being presented at this conference. [1]
Thermal interference in high density magneto-optical recording and a method of compensation
Authors: Lee Tuzo-Chang , Wang Wai W. , Rhea Kerry , Lauffenburger Jim
Published: February 2023

In order to achieve high density recording in a magneto-optical disk, much attention has been paid to reduce thermal interference between the recording pulses1,2. This is because thermal interference causes the variation of the recorded domain size and shape2. The domain size and shape fluctuation introduces peak shift and amplitude variation of the optical readout. This effect is significant3 when the separation between the data bits is small in a high density recording medium. For a disk drive using domain-edge recording, the peak shift introduces timing jitter relative to the timing clock pulse. In a sampled servo disk drive, the amplitude variation results in deterioration of the margin of the amplitude threshold detection4. The timing jitter in edge-recording disk drive and erosion of amplitude threshold detection margin in a sampled servo disk drive both result in carrier-to-noise ratio reduction and thus larger bit error rate of the system. In this paper, a sampled servo drive is used to study the readout amplitude variation due to thermal interference in successive recording pulses. A simple compensation technique is demonstrated to achieve uniform optical readouts of the recording data bits in successive recording pulses.
Extending the Compact Disk Format to High Capacity for Video Applications
Authors: Imaino W. , Rosen H. , Rubin K. , Strand T. , Best M.
Published: February 2023

Optical storage disks with multiple data layers1 offer large potential increases in capacity over standard single layer disks. In this approach individual data layers are spaced far enough apart so that any significant crosstalk is avoided and arc accessed by moving the objective lens in the focus direction. The large numerical aperture of the objective allows data layer separations that arc small enough to permit access by standard focus actuators in existing optical storage mechanisms. This scheme requires no change in the CD format and is fully backward compatible with CD Audio, CD ROM and CDR disks and provides a favorable development path for the delivery of compressed video. Two times current CD capacities would enable playback of MPEG 1 compressed full length movies from a single disk, while higher capacities would permit improvements of the video quality.
Waveguide Optical Scanner with Increased Deflection Sensitivity for Optical Data Storage
Authors: Chen Qibiao , Chiu Yi , Devasahayam Adrian , Siegler Michael , Lambeth David N. , Schlesinger T. E. , Stancil Daniel D.
Published: February 2023

Thin film electrooptic beam scanners [1,2] are of interest for applications such as optical recording and laser printing. We are pursuing a novel waveguide device structure in which prisms are formed by ferroelectric domain inversion in a substrate containing a planar waveguide. The device uses TM optical modes in z-cut substrates and is therefore compatible with waveguides used for optical second-harmonic generation (SHG).
Ring Lens Focusing and Push-Pull Tracking Scheme for Optical Disk Systems
Authors: Gerber Ronald E. , Zambuto James J. , Erwin J. Kevin , Mansuripur M.
Published: February 2023

Most current generation optical disk systems use an astigmatic lens to generate their focus-error-signals (FES). In this presentation we describe a novel technique for generating the FES using a ring lens.1 We show that the new scheme generates a larger FES slope and lower "feedthrough" (induced on the FES by track-crossings during the seek operation) than the astigmatic technique.
Observation of Domains and Grooves on MO Disks with Optical Microscopy and Image Processing
Authors: Ruane M. , Gadetsky S. , Mansuripur M.
Published: February 2023

Simple, nondestructive observation of grooves and magnetic domain structures is important to improved MO disk quality control, performance evaluation, and development of novel disk systems. Direct observation is difficult because groove and domain dimensions are on the order of one wavelength of visible light and, therefore, at the diffraction limit of optical microscopy. Complicating the matter further are the facts that illumination is somewhat non-uniform, contrast is low, and observations must be made through the substrate. A conventional metallurgical microscope has been modified to allow observation of grooves and domains on standard MO disks, using digital image processing to enhance otherwise obscure features.
Recent Progress in Short-Wavelength II-VI and III-V Laser Diodes
Authors: Ooki Hiroshi , Ikeda Masao
Published: February 2023

Recent progress in blue-violet (III-V) and blue-green (II-VI) lasers in Japan will be introduced in conjunction with optical disk application.
Quantitative Study of Nitrogen Doping Effect on Cyclability of Ge-Sb-Te Phase Change Optical Disks
Authors: Kojima Rie , Kouzaki Takashi , Yamada Noboru
Published: February 2023

In phase change optical disks, a phenomenon of micro-material-flow caused the limitation of cycle number. To this issue, it was reported that the nitrogen doping into the recording layer was effective to suppress the micro-material-flow [1]. We successfully determined the concentration of nitrogen atoms in Ge-Sb-Te films [2] by SIMS observations. Based on the result, we quantitatively examined the effect of nitrogen doping on the dynamic disk properties. In this paper, we will present the examination results and discuss the model of nitrogen function in the Ge-Sb-Te recording layer.
Phase-change Optical Disk with Nitride Interface Layers
Authors: Yamada Noboru , Otoba Mayumi , Nagata Ken'ich , Furukawa Shige'aki , Narumi Kenji , Ueno Fumiaki , Akahira Nobuo
Published: February 2023

Our DVD-RAM/2.6GB was just commercialized in this year. Today, our R/D activities are aimed toward the next generation of DVD-RAM media and even the generation beyond that. We are striving to achieve higher recording density, a higher data transfer rate and higher reliability (cyclability). Through our study, we have found that a nitride interface layer was very effective for increasing the performance of phase-change optical disks. In this paper, we will present a new disk structure having Ge-N layers at the interface between the Ge-Sb-Te active layer and the ZnS-SiO2 protective layers. The effects of the nitride layer and the disk performance will also be described.
High performance, high capacity optically assisted Winchester (OAWT™) technology for data storage
Authors: Davis Joseph E.
Published: February 2023

Quinta's optically assisted Winchester (OAWT™) technology integrates optical, magnetic, and telecommunications technologies for the first time in the disc drive industry and is designed to build a new class of ultra-high capacity, cost effective disc drive storage devices. The OAW system consists of four major components; an advanced light delivery system, a miniature head design with integrated optics, a high-bandwidth two-stage servo, and a new recording media composition.
Tradeoffs in binary and nonbinary optical recording
Authors: Vasic Bane V. , McLaughlin Steven W. , Djordjevic Ivan , Djordjevic Goran
Published: February 2023

We consider tradeoffs and storage density limitations in both binary and M-ary optical recording systems that use runlength limited coding. The intention of M-ary recording is to increase the storage density and/or data transfer rate of the disc. However, for a given increase in channel signal-to-noise ratio, it is not clear whether binary coding methods or M-ary coding methods achieve the largest density. In this paper we give fundamental insight to this problem. Particular emphasis is given to the best choice of M, the number of recording levels, and the runlength parameters d and k for a given channel signal-to noise ratio to maximize storage density. The storage channel is assumed to be noisy with an additive white Gaussian noise. The Shannon capacity (and maximum storage density) is discussed and computed for various signal to noise ratios and recording parameters.