bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of Rigorous Vector Coupled-Wave Theory in Design and Tolerancing Studies of Arbitrary Profile Surface-Relief Diffractive Components for Magneto-Optical Heads
Authors: Haggans Charles W. , Kostuk Raymond K.
Published: February 2023

Surface-relief diffractive elements show promise for magneto-optical data storage head applications due to their polarization selectivity, planar geometry, high diffraction efficiency, and manufacturability. In this paper, a rigorous vector coupled-wave model is presented and used in the design and tolerancing of diffractive optical components.
Blue Laser Devices for Optical Data Storage
Authors: Lenth Wilfried , Kozlovsky W. J. , Risk W. P.
Published: February 2023

Presently, optical data storage systems are based on the use of near infrared GaAIAs diode lasers operating at wavelengths of 780 - 830 nm. Substantial advances of the areal storage density are possible by using lasers in the blue - green wavelength range. Such blue - green laser sources can be developed by making use of nonlinear optical processes for frequency upconversion of existing state-of-the-art III-V semiconductor lasers. These approaches circumvent the severe fundamental material fabrication problems associated with the potential development of blue semiconductor injection lasers.
A New Tracking Method for 2-Beam Optical Heads Using Continuously Grooved Disks
Authors: Irie Mitsuru , Takeshita Nobuo , Fujita Teruo , Kime Kenjiro
Published: February 2023

The next generation optical disk drives need to realize shorter access time, higher data transfer rate and higher information density than the present ones. To realize each requirement, several methods were proposed and estimated, for example, usage of visible laser sources[1], multi-beam lasers[2,3], a split-type head structure[4] and so on. Although a split-type optical head with two or more light sources may be one of good solutions, it is not easy to control plural spots on an information track precisely and simultaneously in case of continuously-grooved disks. To solve this problem, we proposed a simple tracking method with composed the conventional twin-spot and push-pull tracking methods[5].
High Speed Recording Technologies for Magneto-Optical Disk System
Authors: Sukeda Hirofumi , Tsuchinaga Hiroyuki , Tanaka Satoshi , Niihara Toshio , Nakamura Shigeru , Mita Seiichi , Yamada Yukinori , Ohta Norio , Fukushima Mitsugi
Published: February 2023

In recent years, magneto-optical disk, for its large storage capacity, is gaining a lot of attention among the various business areas, such as image and document data storage, auxiliary storage for a computer system, and digital video recording. However, it has some problems for its relatively low data transfer rate. Very large capacity optical disk system will be certainly more attractive if they are designed with a very high transfer rate [1, 2].
Magneto-optical Signal Detection with Elliptically Polarized Light
Authors: Arimoto Akira , Nakao Takeshi , Takahashi Masahiko
Published: February 2023

Magneto-optical disks are quite promising, because of their high reliable rewritability and high density recording. However, the signal to noise ratio is not so high compared with write-once or read only optical disks. In this paper, a higher carrier to noise ratio detection method using optical dichroism in magneto-optical materials is proposed.
MD Data System
Authors: Kondo M. , Igarashi T. , Yanaga M. , Ogawa M.
Published: February 2023

The MD Data, a 140 Mbyte compact removable storage system, was developed with a dedicated file structure supporting usage under a multi-platform environment.
Engineering of Compact Green Laser for Digital Video Disk Recorder
Authors: Chee J.K. , Lee H.W. , Jang H.Y. , Lee S.H. , Shin D.H.
Published: February 2023

Most optical data storage systems require compact, continuous-wave laser sources. The desirable features include the maintenance-free operations for the low noise(< −100 dB LIN), small output power drift(< ±3%) within the device life cycle(> 10,000 hours), wide range of operating temperature(10 ~ 35°C) and sufficient output power(> 20 mW). These requirements are easily satisfied with the near infrared semiconductor laser sources that are presently used in the database and audio/video systems.
A Compact, One-Laser, Optical Tape Recording System for High-Definition Digital Video
Authors: van Rosmalen G.E. , Kahlman J.A.H. , van Uijen C.M.J.
Published: February 2023

Since the introduction of digital optical recording in the early eighties, there has been a steady demand for an increased capacity storage medium. Apart from creative approaches such as superresolution, the density enhancement is usually pursued by more conventional techniques, i.e. by reduction of the spot size using shorter laser wavelengths and higher numerical aperture optics.
An Overview Of MO Optical Disk Substrate Manufacturing Technology
Authors: Kwiecien James
Published: February 2023

The first commercial shipments of the ISO standard 5.25" Rewritable Optical Media began in 1988. It wasn't until 1993 that the "2X" double capacity product was introduced. Much of the early disk development activity centered around the thin films. Due to the large performance margins built into the disk/drive system, many of the substrate related issues could be ignored. With the introduction of the "2X" optical disk and the current development efforts on the "4X" product, the substrate quality has been identified as a limiting factor in disk performance. The media manufacturers are presented with the challenge of having to improve substrate performance to accommodate the higher data densities, shorter wavelength lasers, and increased disk rotation rates, at the same time migration of hard disk and tape technology is forcing improvement in the cost-per-Megabyte of Optical systems.
Substrate Birefringence Measurement Techniques
Authors: Kono R.-N. , Jhon M. S. , Karis T. E.
Published: February 2023

A variety of techniques have recently been published for measuring the bulk average values of the MO disk substrate birefringence(1-4). Interpretation of the bulk average birefringence data has been explored in great detail(5). Birefringence in polycarbonate, PC, magneto-optical, MO, disk substrates arises from a combination of frozen-in polymer chain orientation and a volume change during cooling or thermal stresses (6,7). The historical method for evaluating a subsurface stress is to drill a small shallow hole in the surface and observe the strain in the surface surrounding the hole(8). The stress/strain field around stamped in pits in optical disks may produce local fluctuations in the birefringence if the pits are considered analogous to holes drilled in a stressed surface. However, the hole drilling method provides only the stress near the surface.
A Novel Method for Measuring the Vertical Birefringence of Optical Disk Substrates
Authors: Mansuripur M. , Hsieh Yung-Chieh
Published: February 2023

Birefringence measurements of plastic substrates have traditionally relied upon ellipsometric techniques. These measurements are sometimes intrusive, usually elaborate and time-consuming, and typically yield results for only a few selected spots on the substrate. In this paper we describe a new measurement technique which overcomes the above limitations.
Room Temperature CW Emission of II-VI Diode lasers
Authors: Ozawa Masafumi , Ishibashi Akira
Published: February 2023

ZnMgSSe-based II-VI semiconductors are promising materials for making blue and green laser diodes (LD). Haase et al. reported the first demonstration of ZnCdSe quantum well lasers[1]. Room temperature (RT) continuous-wave (CW) operation was the next milestone for practical usage of blue and green LDs. Recently we have achieved RT CW operation of ZnCdSe/ZnMgSSe lasers. To realize RT operation, lattice-matched heterostructures with sufficiently large electrical and optical confinement are essential. These conditions can be satisfied with employing a novel ZnMgSSe alloy, which was originally developed by Okuyama et al.[2], for cladding layers. This alloy offers a wide range of bandgap energy from 2.7 to ~4 eV, while maintaining lattice matching to a GaAs substrate, which gives us the flexibility in designing the LDs. We fabricated a separate confinement heterostructure (SCH), having ZnMgSSe cladding layers, ZnSe waveguiding layers, and a ZnCdSe multiple-quantum-well(MQW) active layer. The structure shown in fig.1 was grown on a (001) n-GaAs substrate by molecular beam epitaxy(MBE). Figure 2 shows the light output against current characteristics at RT measured under continuous and pulsed-current conditions. The CW threshold current (Ith) is 45 mA corresponding to a threshold current density of 1.5 kA/cm2. The typical laser threshold voltage is 17 V. The lasing wavelength is 523.5 nm under continuous operation as shown in figure 3. We have also observed blue stimulated emission at 489.9 nm (figure 4). This blue laser has the same structure as the blue-green laser except for employing a less Cd containing active layer and a p-ZnTe/p-ZnSe MQW layer as a p-contact layer in order to reduce the operating voltage. This MQW layer leads to the operating voltage of 6.3 V.
Pit Depth Encoded Memories
Authors: Marx David S. , Psaltis Demetri , Sirat Gabriel
Published: February 2023

The depth of focus of current optical disk players is between 2 and 3μm.1 By varying the depth of a pit within the limits of the depth of focus, we can squeeze more information into each pit without any loss of pit density. For example, if the pit depth is varied in 0.1μm steps, then each pit can represent between 4 and 5 bits of information.
High Speed And Large Capacity Phase Change Rewritable Disk Recording For Digital Video
Authors: Koishi K. , Furumiya S. , Kobayashi Y. , Kitaura H. , Shimada T. , Edahiro Y. , Furutani T. , Kurahashi A. , Yamada N.
Published: February 2023

A Phase Change Rewritable (PCR) optical disk has advantages, such as direct overwritability and high speed random access suitable for non-linear video editing, but it is necessary to increase both recording rate and capacity in order to realize high quality and long time digital video storage systems. For this purpose, this paper proposes a new Double-sided 4-head MCAV (DMCAV) method and a Mark Edge Recording (MER) technique with a 30cm diameter PCR disk.
Silver Island Films for Write-Once Optical Storage Media
Authors: Baba Kazutaka , Hayashi Kazuhiro , Miyagi Mitsunobu
Published: February 2023

Recently many write-once (WO) storage media have been proposed and investigated, including organic dye and tellurium based alloy, etc. A metal island film is one of the potential WO storage media. It is composed of nanometer-size metal particles (i.e., islands) and exhibits a high reflectance and large absorptance due to the resonance of free electrons in the islands near the resonance wavelength. As the optical properties of the metal island films can be thermally changed, it is expected that an efficient heat-mode WO optical memory is realized by using them. Laser writing was already reported on gold (Au) island films with a 650 nm-Kr laser from the thermal transformation of Au islands [1] and on copper (Cu) island films with an 820 nm-laser diode from the oxidization of Cu islands [2,3].
Ramp Profiles for Optical Disc Incubation
Authors: Wrobel Joseph J.
Published: February 2023

The equilibrium water content of polycarbonate resin is a function of temperature (T) and relative humidity (RH). The difference in equilibrium water content at an incubation condition relative to that at ambient can be problematic if the environment around the polycarbonate is rapidly changed. For example, the formation of visible aqueous microcavities has been reported to occur in samples transferred from a 100°C water bath to a room temperature environment.1 In an optical disc structure, far less dramatic effects, such as the release of a sub-micron thick water film at the information surface, could generate media defects. This paper develops a rational process for acclimating polycarbonate substrate discs to environmental changes that occur during incubation testing.
Compact Optical Head Module Integrated with Chip Elements for Magneto-Optical Disks
Authors: Katayama R. , Ohba A. , Komatsu Y. , Ono Y.
Published: February 2023

Magneto-optical disk drives have been put to practical use for coded data file and digital video file applications. However, in order that they are more widely used as personal computer peripherals or portable video disk recorders, optical heads need to be more compact. A hybrid chip integration technology for a laser diode, a photodiode, etc. is effective for this purpose1). The application of a polarizing holographic optical element (HOE) also meets this requirement, because it can possess many optical functions, such as polarizing beam splitter and error signal detection2). This paper proposes a newly designed compact optical head module for magneto-optical disks, combining the hybrid chip integration technology and the polarizing HOE. The module size is ϕ10mm × t11mm.
Holographic Optical Head
Authors: Yang K.Y. , Noh S.W. , Kim E.J. , Kim T.W. , Kim J.W. , Yoo T.K.
Published: February 2023

One of the advantages of the optical head using HOE (Holographic Optical Element) is that various optical layouts and servo signal detecting schemes are available in a small package[1],[2]. In this paper we will present a new holographic optical head with two-segmented HOE which can generate astigmatic focus error signal and push-pull radial error signal. Design process and simulation result of the focus and radial error signal will be described. The optical head was tested on a CD player and produced a good eye pattern with 3T-jitter less than 40 ns.
Direct Overwrite on a Magneto-Optical Super-Resolution Disk by Magnetic Field Modulation
Authors: Hirokane J. , Murakami Y. , Katayama H. , Takahashi A. , Ohta K. , Ishikawa T.
Published: February 2023

In magneto-optical (MO) disks, the magnetically induced super-resolution (MSR) readout method using an in-plane magnetization layer has a great advantage of high density(1). In order to improve recording characteristics, a new medium structure was developed. Preparing an intermediate layer between the readout layer and the recording layer, we have achieved recording with a weak magnetic field and direct overwriting by a magnetic field modulation method.
High Density Optical Disk Recording by Pit Edge Modulation
Authors: Kobayashi Seiji , de Kock Joost P. , Horigome Toshihiro , Yamatsu Hisayuki , Ooki Hiroshi
Published: February 2023

Many attempts have been made to record multilevel signals on an optical disk, however no one has succeeded in increasing significantly the recording density using this approach. In this paper we present a novel method to obtain a multilevel rf signal by modulating the position of the pit edges. With this method we utilize the theoretically available SNR margins not yet implemented in current optical disk systems. Thus we can achieve higher recording densities even when using a conventional pick-up.
Full Digital Video Read Write Disk Drive Using M-ary Coding
Authors: McLaughlin Steven W. , Gerpheide John M. , Earman Allen M.
Published: February 2023

We consider the application of real-time storage at full digital video rates. Traditional optical recording systems utilizing binary runlength limited coding, cannot support the coding density required for the data rates and capacities. New optical recording channels [1], have been developed that support non-binary, M-ary (M≥3) coding. In this paper we consider linear optical recording media (such as demonstrated by Optex’s proprietary stimulable phosphor material called Electron Trapping Optical Media, ETOM™) and the system design (see Figure 1) to support the full digital video rate. The system uses a new class of runlength limited M-ary codes, that was constructed using a modified version of the state splitting algorithm due to Adler Coppersmith Hassner[2], These codes increase (by 2-3 times) the data rate and storage density on the disk and improve on the minimum squared Euclidean distance to provide coding gains of up to 1.9 dB above Ungerbock-style trellis codes used for amplitude modulation.
Direct Overwrite for Fixed Bit-Cell Encoding
Authors: Hatwar T. K. , Victora R. H. , Palumbo A. C.
Published: February 2023

We have recently introduced a new direct overwrite (DOW) scheme for magneto optic (MO) recording based on the double compensation point media using light intensity modulation [1]. The major advantages of this scheme are the elimination of the initialization magnet, simpler disk structures and a wide range for Curie temperatures, thicknesses, and coercivities of the individual layers. One configuration consists of two magnetic layers (memory and reference having perpendicular anisotropy) exchanged coupled through an intermediate soft magnetic layer. The second media configuration consits of only a memory layer and an intermediate layer. The memory layer has a Curie temperature that is greater than, or approximately equal to that of the reference layer. The intermediate layer has a higher Curie temperature than either the memory layer or the reference layer. The room temperature coercivity of the memory layer is higher than that of the reference layer. The combined magnetization of the coupled layers exhibits two compensation points: antiferromagnetic coupling occurs between the memory and reference layers over at least part of the temperature range. The thickness and composition of the two layers are chosen so that the combined system has a compensation temperature above the ambient temperature but below the write temperature. When such a medium is irradiated with low power (Plow) and high power (Phigh) laser beams under constant bias field, the magnetization of the memory and reference layers change as shown in Fig. 1.
High-Speed Response to Laser Heating and Cooling in Thermo-Magnetic Recording on Magneto-Optical Disk Memory
Authors: Miyata Kazutomo , Saito Jun , Akasaka Hideki
Published: February 2023

The achievement of high-speed capability, a large memory capacity and low cost technology is the main theme for developing Magneto-Optical (MO) data storage devices. In order to achieve the high-speed capability, we have some means such as multiplying data channels, direct overwriting and high-speed modulation. For realizing the high-speed modulation, MO disks have to have the property of high-speed response to laser heating and cooling in thermo- magnetic recording. The MO disk's thermal response ; 1-exp(-t/τ) (heating) and exp(-t/τ) (cooling) has a representative parameter τ1). The t is the time in the modulation process. The smaller the τ is, the faster the MO disk responds to the modulation. In this paper, we experimentally and analytically investigate the medium velocity dependence of τ.
ASMO Technology
Authors: Kwiecien James Z.
Published: February 2023

Summary not available.
Magneto-optical properties of garnet multilayer film for wavelength multiplex recording media prepared by laser ablation
Authors: Ishii Norihiko , Tamaki Takahiko , Tanaka Isao , Sato Ryuji
Published: February 2023

Bi- substituted dysprosium iron garnet (BixDy3-xFe5O12;Bi:DyIG) films are promising material for magneto-optical (MO) memory because of their large Faraday effect in the short wavelength region (λ ≈ 350-800 nm)[1]. Usually, Bi:DyIG films have been prepared by the reactive ion beam sputtering and rf magnetron sputtering method. These methods, however, have some disadvantages. One of them is the difficulty of composition control, especially the Bi content, because of its high vapor pressure. The laser ablation method has been used for preparing Bi:YIG films because of ease of controlling the film composition[2].
High Density Phase Change Optical Recording Using a Solid Immersion Lens
Authors: Hirota Kusato , Jo Joshua S. , Milster Tom D.
Published: February 2023

The data density of the optical recording disk mainly depends on the light beam spot size. In conventional optical recording system, the beam spot size, which limited by the optical diffraction limit, can be reduced by using the shorter wavelength light source or larger NA objective lens. Recently, near-field optical techniques have been developed to overcome the defecation limit. In particular, Betzig et al.1) have applied the scanning near-field optical microscope (SNOM) optics, which has a tapered fiber prove with sub-micron aperture, for the recording of magneto-optical (MO) media. However. the low optical coupling efficiency of this fiber prove need a further improvement for practical data storage application. For another approach. Terris et al.2) have developed near-field optical recording optics using the solid immersion lens which has been developed as the optics for a microscope by Mansfield and Kino3). They have demonstrated recording of the 350 nm diameter mark on MO media by using the truncated spherical shaped SIL.
Magnetically Super Resolution for Optical Read Only Memory Disks
Authors: Birukawa M. , Miyatake N. , Suzuki T.
Published: February 2023

A new MSR-ROM method for high-density recording, utilizes the difference in coercivity between “rough” and “smooth” are as in a disk. This method is advantageous for mass production and for the compatibility with erasable magneto-optical recording using MSR. A recording density more than 5 Gbit/inch2 is expected in this method, the same as the double mask type MSR technique in rewritable disk. This paper describes the principle of MSR-ROM and the results of a readout experiment.
SERODS: A New Medium for High-Density Optical Data Storage
Authors: Vo-Dinh Tuan , Stokes David L.
Published: February 2023

Recently, extensive efforts have been devoted to investigating new generations of data storage devices based on nonmagnetic principles, such as optical data storage systems. Optical data storage systems can provide a unique combination of superior performance features that make them most appropriate for large-memory applications. Optical data storage disks also promise to offer low cost-per-byte, improved accessing characteristics and higher storage efficiency.
Signal Properties of CD, CD-R and CD-RW Compatible DVD-RAM Pickup
Authors: Lee Chul Woo , Seong Pyong Yong , Ryoo Byung Ryul , Lee Yong Hoon , Lee Yong Jae , Kim Tae Kyung , Yoo Jang Hoon , Kim Seok Jung , Son Yong Ki , Shin Dong Ho
Published: February 2023

We describe techniques that have been used to realize a CD, CD-R and CD-RW compatible DVD-RAM pickup. One objective lens having two aspherical surfaces can be used to read both DVDs and CDs. Chromatic aberration of beam shaping prism which resulted from reading/writing laser power change can be corrected by combining two prisms. And a holographic optical element (HOE) can be used to reduce push-pull tracking offset by detector deviation.
An all-solid-state continuous-wave 266nm laser for optical disk mastering
Authors: Oka Michio , Takeda Minoru , Kashiwagi Toehiyuki , Yamamoto Masanobu , Sakamoto Michibiko , Kondo Kenji , Tatsuki Kouichi , Kubota Shigeo
Published: February 2023

Progress in short-wavelength laser diodes and near field techniques urges the development of ultra-high density disk mastering. Argon ion lasers have been the choice for the purpose. However, the lasers are inefficient and require water-cooling, which is not suitable feature due to induced vibration, moreover available wavelength for stable operation is limited to 351 nm.
Thermal modeling of phase change optical recording disk
Authors: Shi L.P. , Chong T.C. , Liu Z.J. , Ho J.J. , Xu B.X. , Miao X. S. , Huang Y.M. , Tan P.K. , Lim K.G.
Published: February 2023

Erasable phase change recording is an emerging technology for achieving high density data storage. In the case of phase change optical disks, recording and erasing are achieved by the crystllographic structure changes of thin films when the films are heated by laser irradiation. Reproduction of the recorded information is performed by detecting the reflectivity changes caused by the differences in optical constants between the crystalline and the amorphous states. The amorphous state is realized by heating the material film with sufficient laser irradiation power to melt the material over its melting point, and rapidly quenching it to room temperature. The crystalline state is achieved by annealing the film at a temperature between the crystallizing temperature and the melting point. Thus, the calculation of the temperature distribution and the determination of the influence of factors such as media composition, laser power, duty cycle and scanning speed, and disk layer structure are important issues to be considered when attempting to improve the quality of optical disk recordings.
Calculation of focal positions in an optical head using a four-beam laser diode
Authors: Shinoda Masahisa , Kime Kenjiro
Published: February 2023

Calculation method for focal positions in a multi-beam optical head using a multi-beam laser diode with astigmatic difference as a variable is introduced, and some calculated results are presented.
Optical Memory Using Resonant Raman Pulse Excited Spin Echoes
Authors: Ham B. S. , Shahriar M. S. , Kim M. K. , Hemmer P. R.
Published: February 2023

Optical data storage has been interested in several decades because of the potential of fast access time and high-density storage. Recently volume holographic data storage technique has drawn much interest as new materials and improved techniques have developed.1 However, the large of hologram storage is restricted by low diffraction efficiency and mainly focused to read only memory because of the material's characteristic difficult to rewrite in short time interval. Another optical memory technique (photon echo optical memory)2 based on time-domain has developed since 1980's and made big progress for the area of real time image processing and dynamic random access memory. In this technique, data pulses interfere with timely separated write pulse (reference), and their interference pattern is written as population gratings. A read pulse (reference) retrieves each data pulse information as a four-wave mixing process. The write and read pulse separations are restricted by phase and population decay times of the material, respectively, and storage density is determined by the ratio of inhomogeneous to homogeneous linewidths. Even though photon echo technique has advantages of fast access time (≥ ns) and high-density (≥ Mbits/laser spot), its operating temperature is kept extremely low around liquid helium temperature. This is because that homogeneous decay time rapidly shortens as temperature increases due to phonon interactions, i.e., the ratio of inhomogeneous to homogeneous decay rates is ~ 1 at liquid nitrogen temperature (77 K) in a rare-earth doped solid, so that restricts its applications.
Tilt Analysis of Readback Signals from DVD-ROM Media
Authors: Sarigoz Fatih , Kumar B.V.K Vijaya , Kowarz Marek
Published: February 2023

Although not considered a major problem for CDs, tilt is now being looked on as one of the major sources of distortion for the DVD mainly due to its smaller feature size and track pitch.
Multiplexed Holograms for the Microholographic Storage Disc
Authors: Eichler H. J. , Kuemmel P. , Orlic S. , Schulz R. , Wappelt A.
Published: February 2023

We propose optical discs that store data holographically in three dimensions by combining multiplexing techniques and multilayer storage. Microholograms can be stored overlapping in the same volume by using angle multiplexing, wavelength multiplexing or the combination of both. Storage of multiple information bits in one single position on the disc increases the data rates and the storage capacity can reach more than 100 Gbytes /1/. In contrast to previous holographic storage systems, the storage media are made of cheap and mass-produceable photopolymer layers instead of expensive crystals. Furthermore, the microholographic storage method can be downward compatible with today's Compact-Disk (CD)- and Digital-Versatile-Disk (DVD)-systems.
Investigation of the optical system using the Lissajous patterns of the DVD-RAM disk
Authors: Lee Yong Jae , Seong Pyong Yong , Ryu Byung Ryul , Lee Yong Hoon , Kim Tae Kyung , Yoo Jang Hoon , Kim Seok Jung , Son Yong Ki , Lee Chul Woo
Published: February 2023

We have been developing the optical pickup to record and reproduce various data on DVD-RAM disks. Regarding the objective lens of high numerical aperture and laser diode of short wavelength used for DVD-RAM compare to those of CD, it is very important for DVD-RAM disk to verify the degree of disk tilt and defocus under the operating condition because the signal quality including the recording characteristics are greatly influenced according to disk tilt and defocus.[1]
Feasibility Study on Near field Optical Memory Using A Catadioptric Optical System
Authors: Lee Chul Woo , Cho Kun Ho , Chung Chong Sam , Yoo Jang Hoon , Lee Yong Hoon
Published: February 2023

Recently, technologies related to optical memory using near field optical phenomena have been studied [1],[2].
4.7-GB DVD-RAM
Authors: Miyamoto M. , Ando K. , Anzai Y. , Hirotsune A. , Ushiyama J. , Toda T. , Kando H. , Terao M. , Nishida T. , Maeda T.
Published: February 2023

The DVD is acknowledged as the image and information storage media for the next generation of video, music, and computer systems and also for a broad range of other applications. The market for DVDs has already taken off, and the DVD family is looked to as being a united system for image and information. Compatibility among DVD formats is essential for the 4.7-GB DVD-RAM. The key concept of this is large capacity without placing a burden on the readout system.
Partial Response Equalization with Nonlinearity Compensating Signal Asymmetry in DVD Storage
Authors: Hwang In Seok , Lee Yong Hoon , Seong Pyong Yong , Ko Jungwan
Published: February 2023

One approach to increase the capacity of DVD-RAM storage systems is to employ a PRML receiver, which consists of a linear equalizer for partial-response (PR) shaping, and a maximum likelihood sequence estimator (MLSE) [1] - [3]. When a PRML receiver is applied to an optical storage system, its performance tends to be degraded due to the signal asymmetry caused by the nonlinearity of photo-detectors and inaccurate write current control [4]. In this paper. we propose an equalizer with zero-memory nonlinearity for PR shaping and show that the proposed equalizer can outperform conventional linear equalizers.
New Super-resolution Masking Layer Applicable to Both Rewritable Phase-change Disks and ROM Disks
Authors: Shintani T. , Moritani K. , Hirotsune A. , Terao M. , Yamamoto H. , Naito T.
Published: February 2023

In the field of optical disks, higher recording density beyond the wavelength limit is desired. Super-resolution techniques have been studied to circumvent the wavelength limit not only in magneto-optical disks but also for ROM disks using a phase change material [1] or photoreactive organic materials [2][3]. Those methods, however, have some drawbacks: 1) readout cyclability is limited, 2) they are applicable only to ROM disks, because writing and reading many times damages the masking layer.
Variation of the Complex Refractive Indices with Sb-addition in Ge-Sb-T Alloy and Their Wavelength Dependence
Authors: Kim S. Y. , Kim S. J. , Seo Hun , Kim Myong R.
Published: February 2023

With the increasing demand of the cost effective optical recording system, the optical media based on the phase-change phenomena have attracted an extensive research interest. One of the commonly used recording material for the phase-change optical disk is Ge-Sb-Te (GST) alloys which show a reversible phase transformation between the crystalline and the amorphous, thus the corresponding reflectivity change.[1,2] It has been reported that GST-alloys near to the stoichiometric compound are suitable for high speed application while other alloys like In-Sb-Te and Ag-In-Sh-Te are reported to be appropriate for low -speed applications.[3,4] The main purpose of this research is to study the feasibility of GST-alloys for the blue wavelength region for both high density recording and linear velocity applications. Variation of the complex refractive indices with Sb-addition in GST-alloy and their wavelength dependence were studied in the present research by using spectroscopic ellipsometry (SE) and atomic force microscopy (AFM). The reflectivity spectra of GST with different chemical compositions were calculated using these optical constants, and compared with the measured spectra.
Digital Holographic Storage
Authors: Curtis Kevin
Published: February 2023

The status of holographic storage will be discussed.
How to Buy Optics without Excessive Praying and Paying
Authors: Olson Valerie F.
Published: February 2023

This paper will treat a general flow of tasks found useful in maximizing the probability of success (while minimizing cost) for a variety of optics. Different emphases to be placed on subtasks of this approach for prototypes, production and standard pieces will be covered There will even be some useful hints on how to gauge to expected quality of parts by visiting optical shops.
Buyer and Seller Communication
Authors: Moe Paul D.
Published: February 2023

The procurement of precision optics in a high rate production, DOD, environment requires constant communication. This communication must involve the buyer, supplier and engineering personnel, and is of great importance from the point of initial design release through the completion of the production effort.

The education/training of the individual buyer can become critical in attempts to interface between the engineer and the supplier. The ability of the buyer to have understanding of basic optical engineering and contractual knowledge can reduce time and cost consuming efforts as related to problem solving, incorporation of changes and impact on production schedules.

The buyer must be able to transmit basic contractual requirements. to his own engineering staff. These involve many requirements not normally considered by engineering, such as, socio-economic requirements, normal terms and conditions established by DOD and the buyer's company, material availability and cost considerations.
Optical Testing on the Nova Laser Fusion Program*
Authors: Thomas Norman L.
Published: February 2023

NOVA is a ten-beam, seventy-four cm output aperture Neodymium:fluorophosphate laser designed to perform laser fusion experiments at 1054 nm wavelength 80-120 Kilojoule and 100 ps to 3 ns pulse length. The cost of the initial phase is $134M with approximately 90% of that being for outside procurement. The laser contains several thousand optical elements including polarizing beamsplitters, laser rods and amplifier disks, aspheric lenses, spatial filter lenses and turning mirrors.
Part Support Studies for Diamond Machining Mirrors
Authors: Robinson S. C. , Gerth H. L. , Stoneking J. E.
Published: February 2023

The manufacture of precision optical surfaces by diamond machining requires a high quality diamond tool, a low vibration, high precision machine, .a stable environment and rigorous machining practices. A view of a diamond turning machine at the Oak Ridge Y-12 Plant(a) is shown in Figure 1. This type of machine is being used.to produce optical surfaces on mirrors such as shown in Figure 2. This mirror, having dimensions as shown in Figure 3, is machined by turning about the mirror centroid. As with any machining process, the technique used to hold the part during machining is critical when trying to achieve an accurate contour. Part–holding errors can arise from centrifugal forces, part motion with respect to the fixture, or distortions introduced into the part by the fixture. A good fixturing technique will minimize these errors but must not be too cumbersome.
Surface Profile Determination Using a Two-ball Spherometer
Authors: Parks Robert E. , Anderson David S.
Published: February 2023

The fabrication of mirrors having large departures from a sphere has always been difficult due to the lack of an easy and effective way of monitoring the figure as it is ground into the surface. Grinding in the figure is much faster than polishing so it is a ground surface which must be monitored. This rules out most optical tests. During the fabrication of a 56" off-axis parabola which departs from the best-fit sphere by 125 microns, we developed a simple method of determining the surface profile Using a two-ball spherometer. The method can be applied to any arbitrary circular profile where it is possible to use the spherometer.
Interferometry By Diffraction Plate and Scatter-Plate
Authors: Cross Eugene W.
Published: February 2023

Interferometry has gained general acceptance as the most credible single test means for the optical system or component whose optical path difference (OPD) must be a few wavelengths of light or less. The optical shop must be capable of delivering not only the optic that the customer ordered, but also an interferogram demonstrating the optic's quality.
Optical Tests Using Fibers, Balls, and Ronchi Gratings
Authors: Parks Robert E.
Published: February 2023

Optical fibers and ball bearings can be used as test tools. An optical fiber may be easily fashioned into a bright source that causes a minimum of obscuration. Ball bearings may be repolished to nearly perfect spheres and used as autoreflecting optics at nearly suitability sible foci in certain tests. Finally we look at the Ronchi test and discuss its suitability as a test device in many differing situations.
Compact Optical Test Facility for Evaluating Very Long Focal Length Mirrors
Authors: Bennett H. E. , Shaffer J. J.
Published: February 2023

Various techniques have been used to test the optical figure and radius of curvature of optical flats and long focal length optics1. If optical flats become too large to be handled manually, they are often measured using a variant of the Ritchie-Common test, although Fizeau and Twyman-Green interferometers have also been used. The familiar knife-edge test is an excellent means for measuring the optical figure of a flat qualitatively using a well-corrected large parabola on an optical bench. It is also useful for measuring the figure and radius of curvature of concave spherical mirrors. If the radius of curvature is in the 10- to 100-m range, however, as is common for laser optics, air turbulence reduces the accuracy of the measurement. A more quantitative technique for recording the optical figure of long focal length optics and determining their radius of curvature is to use a "transmission sphere," basically a Fizeau interferometer modified for converging or diverging light. Parallel light incident on the transmission sphere is focussed by the lens, whose surface on the sample side is accurately normal to the exiting light beams. It thus is the reference surface in the modified Fizeau interferometer. Transmission spheres can be obtained in a variety of focal lengths and f numbers, but they are quite expensive and are specific for a relatively short range of f numbers in the mirrors tested. Air turbulence is a problem for long radius of curvature mirrors just as it is in the knife-edge test. The Zygo Corporation, which manufactures transmission spheres, also manufactures large beam expanders for testing optical flats of 30 cm (12 in.) in diameter or more. However, such large beam expanders are quite expensive. This paper describes a relatively inexpensive technique using the Zygo interferometer and one or more transmission spheres together with a large parabolic mirror or well-corrected lens and a fringe analysis system for testing both large optical flats and large, long focal length concave or convex mirrors. A range of focal lengths extending to infinity can be measured without utilizing long path lengths, thus minimizing air turbulence problems. Both concave and convex mirrors can be measured using the same transmission sphere, and unlike most other techniques for measuring long focal length optics, the longer the focal length the better the system operates.
Impact Of Lathe Geometry Errors On Diamond Machined Surfaces
Authors: Johnson J. R.
Published: February 2023

In the course of diamond turning activities on Honeywell's two-axis lathe, it became desirable to attempt to calculate the shape of the surface produced by making a purely phenomenological model of the process. It was assumed that the slide ways are truly straight, that the lead screws are perfectly regular, that the tool feed rate is quasistatic, that the shape produced is the locus of the point of contact between the tool and work. The model retains only angular misalignment errors, which are errors of machine construction, and tool offset errors, which are errors of the tool set up procedure.
The Influence Of Physical Configuration Upon The Quality Of Injection Molded Lenses
Authors: Lytle John D.
Published: February 2023

While it is true that polymer optical elements are able to closely emulate their glass counterparts in both exterior appearance and optical surface figure, the design freedoms which are available through the injection molding process permit polymer optical elements to be manufactured in forms which are considerably more complex than are possible in glass. This enables the optical systems designer to integrate several optical and mechanical functions into a single part. The integral molding of spacers, centration flanges, and so on is well publicized and won't be discussed here. Some tradeoff relationships between mechanical complexity and optical quality do exist, however, and these should receive serious consideration in the conception of the instrument.
Replicated Diffraction Gratings
Authors: Gomez G.
Published: February 2023

Summary not available
Optics Standards
Authors: Detrio John A.
Published: February 2023

Optical techniques and optical instruments play an important role in many advanced technologies. Optics is also a very mature technical subject. This combination of maturity and application to high technology has created a rather uncoordinated standardization effort. For optical components, the most frequently cited specifications are those developed by the military for procurement purposes. Radiation measurements are divided between the illumination engineering community, spectrophotometry, and laser radiation measurements. Standards for photographic optics have been developed primarily in response to the commercial needs of the manufacturers. Fiber Optics is a growing technology in which standards work is actively being pursued to satisfy military and commercial needs. The demands of the semiconductor fabrication industry for quality optics for very high resolution photolithog­raphy applications has stimulated interest in standards for optical microscopy. The standards writing groups working on optical standards will be identified. The topics of some of the standards committees applicable to various fields of optics will be summarized.
How to make cylindrical optics
Authors: Karow Hank H. , Wolf Gerhard A.
Published: February 2023

This paper covers the fabrication of cylindrical components using
standard optical shop equipment and mechanical aids.
Cleaning a Laser Disk by the Drag-Wipe Method
Authors: Giove J. , Guscott B.
Published: February 2023

Summary not available.
Handling Chemicals in the Laboratory: (Information Sources on Toxicity and Controls)
Authors: Panel Speakers
Published: February 2023

The laboratory and pilot plant research worker in optics encounters a wide range of chemicals. In many cases there are little data available on the effects from exposure. One is not normally concerned with handling gram amounts of material once or twice a year, but frequently interesting materials are followed for extended periods resulting in chronic exposure to low concentrations over a period of time. Some of you are acquainted with the data base available on the toxic effects from these chemicals. For those of you who are not, I intend to introduce you to selected sources of information and prepare you for the interpretation of that data. In the second part of my talk I will discuss one control technique -- the laboratory hood and how one can use it effectively.
Processing for Dimensional Stability
Authors: Paquin R. A.
Published: February 2023

Summary not available.
Aspheric Surface Errors from Foucault Test Data
Authors: Holleran Robert T.
Published: February 2023

The numerical integration of Foucault test data is simplified when readings are taken for the centers of contiguous zones of equal area. Height errors from the reference surface are shown to be proportional to the simple sump of knife-edge shifts from nominal settings. Change of reference curvature for minimum zonal error is effected by changing each shift by the same amount. Errors are exact to third-order for conic surfaces. The method is especially helpful when many tests must be made in the figuring process. Formulas are derived and an example is given, using both arithmetical and graphical error adjustment.
Space Telescope Primary Mirror
Authors: Strickland John C.
Published: February 2023

Eastman Kodak Company, under subcontract to Perkin-Elmer Corporation, is polishing the 97.5-inch mirror shown in Figure 1 for the Optical Telescope Assembly being built by Perkin-Elmer under contract to NASA. Specifications for the mirror are listed in Table 1. Discussion of this fabrication will include a quick summary of the overall process, as well as a detailed discussion of the aspheric grinding and measurement. In addition, an interferogram summary of the polishing, including the most recent test prior to the OSA Workshop, is presented.
Specialized Interferometric Testing Techniques
Authors: Bacevic J.
Published: February 2023

Summary not available.
A Simple Test Method for Conic Surfaces
Authors: Shafer David
Published: February 2023

Descartes described the conditions which allow a single lens with one conic surface to image a point to a point, with no spherical aberration of any order. The results, which depend on the index of the glass, only give a solution for certain conic eccentricities. This paper shows how to generalize Descartes' approach so that any conic can be conveniently tested, providing the size of the piece is not too large.
Testing Forged IR Optics by Holographic Techniques
Authors: Leung K.M. , Schmit F. , Anderson R.
Published: February 2023

When forging spherical or aspherical lenses, a large difference in the optical figures can be found between the forged lens surface and the diamond-turned die. A two-wavelength holographic technique can be used to test the forged lens surface when the resulting interferograms are too complicated to analyze. However, when the difference is small, or when an aspheric die is to be evaluated, another unique holographic technique is available which uses a computer generated hologram for the null optics. This paper describes these two holographic techniques for testing the forged ir optics at the visible wavelengths.
A User’s Guide to Designing and Mounting Lenses and Mirrors
Authors: Kowalskie Bryan J.
Published: February 2023

This guidebook is a practitioner-oriented supplement to standard texts in optics and mechanical engineering. It reflects the author’s practical experience with the oftentimes troublesome aspects of effectively integrating optical components with mechanical hardware. Accordingly, its focus is on the techniques, assumptions, and levels of design sophistication needed for a wide variety of sizes and optical surface quality levels. It is intended to be a primer for engineers, designers, and draftsmen already familiar with some of the problems encountered in mounting optical components and who are responsible for developing components for high-energy laser systems.
"A Method of Optical Fabrication of Indium Antimonide"
Authors: Cave Thomas R.
Published: February 2023

Indium antimonide has been found to be very difficult to optically fabricate to a high order of surface quality and figure. The following method now allows this to be accomplished.