Optical Disk Recording Research Articles

Optical recording disc

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Applications of Scanning Tunneling Microscopy in the Materials Characterization Laboratory

Scanning tunneling microscopy, first developed by G.Binnig, H.Rohrer, Ch.Gerber, and E.Weibel [1] in 1982 as a method of directly observing atom sites at the surface of graphite and other crystalline materials, is now being used in an ever increasing variety of applications as a result of steady and rapid advances in instrumentation, interpretation, and specimen handling techniques [2]. As a result the STM is widely recognized as a powerful method of observing surface structure on an atomic scale and is fast becoming an accessory tool in materials characterization laboratories that are devoted to solving industrial problems. Some examples representative materials characterization studies are described in mis paper.The first STM studies employed its high resolution capabilities for fundamental studies of the topography of atoms at surfaces [2]. More recently the value of the STM to observe both surface topography and electronic structure has been utilized. Figure 1 is a STM image of a charge density wave (CDW) from a TaS3 sample at 143K[3]. In this work the advantage of STM, due to sensitivity to both surface topography and electron structure, is apparent.The development of long scan STMs with scan capabilities of several micrometers or more has opened up a whole new class of materials where the magnifications required are comparable to that of a conventional SEM. The 3-dimensional structure of a processed optical recording disk, as revealed by the STM, is illustrated in Figure 2. The ability of the STM to observe both the course and ultrafine structure of such a sample makes it a powerful tool for relating processing conditions to surface structure defects and hence to the quality and reliability of the optical storage disk itself.

Patterns of cell movement in early organ primordia of the chick embryo

Purse-string constriction of the cytoskeleton at cell poles is generally accepted as the causal mechanism for invagination during early stages of organ formation. However, it is known that other cell movements, including intercalation, play a role in the organotypic shape changes that occur during gastrulation and neurulation. Such cell movements have not been investigated in pouching and branching epithelial primordia. There is reason to suspect that cells within these organ primordia might exchange their neighbors for others, that is, intercalate or translocate, at sites of sharp folding such as borders with the surrounding epithelial sheet or where a bend occurs within the primordium. The greatest difficulty in identifying these movements has been the need to use intact embryos so that the processes are not distorted. This study explores the possibility of using time-lapse video recording to identify cell movement at these locations. Three organ primordia were tested: otic and thyroid placodes, which had not been tested previously, and neural plate as a control, where movements of this sort have been documented. Embryos or parts containing the primordia were immobilized and cell apices visualized with Hoffman modulation contrast optics. Recordings to an optical memory disc recorder were transferred to a microcomputer for image analysis. The viewing procedure allows reasonably clear visualization of cell apices, and image analysis permits tracking of a number of adjacent cell apices over an extended time period. Several types of movement were found to occur within cell sheets, and the relative abundance of each type depends on the specific primordium. In the neural plate, some cells move many cell diameters from their neighbors. In the other two primordia, most cells show limited shifts in position relative to their neighbors except at regions where folds are formed. In other regions, adjacent cells move as a unit. Knowledge of the movements which occur in any particular primordium is essential to an understanding of the mechanisms controlling its formation.

High density recording by superresolution in an optical disk memory system

High density optical disk recording using an optical superresolution technique is proposed. By setting a shading band in the center of the collimating beam, the focused spot size on the recording medium is reduced to 80% compared with that of a conventional optical recording. The readout signal degradation affected by the focused spot sidelobe on the recording medium is suppressed by spatially extracting the main lobe region from the reflected back beam using a slit on a reimaged plane. The linear recording density has been improved to 1.2 times as high as that for a conventional optical recording using a normal resolution optical head.

瀬戸内海大型水理模型における流れの可視化

The hydraulic model experiment for a tidal basin requires a log term flow measurement in wide area, keeping its spatial high-measurement density. To fulfill these requirements, we developed an image processing system. The system installs a optical video disk recorder, A/D and D/A converter with LUT and can record successively four visualized flow images at the same time provided that a proper time interval is given. We use many white plastic balls as floats to visualize flows and require the system to process the float images with a high speed. This image processing is done by the hardware of the A/D and D/A converter which turns over the processed data to the float analysis.The float analysis adopted here lays stress on unique pairing of floats and requires their coordinates and members around the float to be paired in two scenes at different time. A pairing algorithm is proposed and tested by the experiment data which is obtained in the Seto Inland Sea hydraulic model and covers flows around islands and bay mouths.

光ディスク記録の動向

光ディスク記録の動向

Diffraction-limited circular single spot from phased array lasers

Anamorphic prism optics makes it possible to obtain a diffraction-limited (lambda/8) circular single spot from index guided phased array lasers. It served not only for beam shaping but also for astigmatism correction and spatial filtering. The optical path analysis based on the interferometric fringe scanning phase measurements both in the near and far fields indicates that the phased array lasers can be applied to such diffraction-limited precise optical systems as optical disk recording, laser beam printing, or second harmonics generation.

Optical and thermal analyses on multilayered thin films of a phase-change optical recording disk

A computer simulation method to study a laser-induced transient temperature profile of a multilayered phase-change optical recording disk (PCORD) has been developed. The simulation program consists of two parts. One part is an optical analysis program based on the optical characteristic matrix method, and the other is a thermal analysis program based on the finite-element method. A new estimation method for thermal conductivity of recording films was proposed. The estimated thermal conductivity of the thin-film recording media was found to be 50% lower than that of the bulk. Reflectivity, absorbance, and temperature values obtained with this simulation method were compared with those measured by a spectrophotometer and an infrared radiation thermometer when the samples were irradiated in an Ar+ laser beam. The accuracy using this simulator was within 8% for reflectivity and absorbance and within 10% for temperature. A method of optimizing the laser-absorbing layer was studied. With this method simulations showed that the PCORD had a maximum contrast ratio and minimum recording time when thickness, thermal conductivity, and complex refractive index of the laser-absorbing film were 60 nm, 4.2×10−3 W/cm °C, and 2.6−i⋅0.0, respectively. This simulation could provide better film designs for PCORDs and the other optical disks of heat mode recording.

High power and low optical feedback noise AlGaAs single quantum well lasers

GaAs/AlGaAs single quantum well self-aligned lasers have been developed for optical disc recording. The lasers emitting at 834 nm have realised low optical feedback noise as well as high output power. The lasers have shown less than −130dB/Hz relative intensity noise at 3mW, and stable 50 mW operation (over 500 hours at 50°C ambient).

Small astigmatism, high power and low noise 0.78 µm self-aligned lasers

0.78 µm self-aligned AlGaAs lasers have been developed for optical disc recording. The lasers have shown a small astigmatism (<3 µm), low-noise characteristics (RIN < −126 dB/Hz at 3 mW) and stable 30 mW operation (over 1800 hours at 50°C).

An Optical Recording Disk Using an Organic Dye Medium in Regard to Provide Interchangeability to the Disks Using Different Organic Dyes

An Optical Recording Disk Using an Organic Dye Medium in Regard to Provide Interchangeability to the Disks Using Different Organic Dyes

Time lapse records of cells in vitro using optical memory disk and cell analyzer

A system has been developed for making automated cinematographic records, using the Cell Analyzer imaging apparatus and an optical memory disk recorder (OMDR). The system is particularly useful when numerous individual cells must be followed over an extended period in a single experiment where the cells are growing in a multichamber tissue culture vessel, or are sparsely distributed within a single flask. The system is programmed to revisit each cell location at a prescribed time interval and to record a video frame on the OMDR. Each frame is stored on a preselected position on the optical memory disk under computer control so that individual records of each cell can be played back in sequence at a selected speed immediately after the experiment. The system can also make use of the Cell Analyzer imaging functions, such as the tracking of cell positions and quantitative measurements of morphologic cell features.

Influence of melt viscosity on the writing sensitivity of organic dye-binder optical-disk recording media

The writing sensitivity of dye-binder optical recording media has been defined as the rate of change in the recording response of the medium as a function of laser power. That response was measured by the electronic readout of the recorded pits and shown to be a function of the viscosity of the binder. The variation in dye-binder media sensitivity was 98% accounted for by variations in binder viscosity and writing laser power. For nonpolymeric systems, a more general regression model was formulated using the glass-transition temperature of the recording medium as a substitute for its viscosity. Thus, for any given dye-binder system, writing sensitivity can be largely predicted from the dye T(g), the binder T(g), and their relative concentration, assuming optimum optical efficiency.

Optical memory disks in image data-base management for cytometry

Many applications in image cytometry require storage and retrieval of a large number of high-resolution color video images. For this purpose, a microprocessor-controlled image cytometry database system has been developed which employs optical memory disk recording and graphics overlay capabilities. The image data base is recorded on optical disk, while associated descriptors are stored in the computer memory in a relational data base. The system has been designed for several applications, some of which require real-time access of individual images. The modular structure of the system permits various experimental configurations as well as integration into an image cytometry apparatus.

Summary Abstract: The correlation of pit shape with the valence state of Ti in Te–Se–Ti alloy thin films for optical recording disks

First Page

追記型光ビデオディスクレコーダを利用したビデオ／データ混在ファイルシステム

追記型光ビデオディスクレコーダを利用したビデオ／データ混在ファイルシステム

Laser diodes are power-packed: Single-mode laser diodes have a rosy future, both as individual sources of power up to 100 milliwatts and in arrays promising up to half a watt

The ultimate power limits of current diode-laser structures are considered, along with the prospects of new applications. After explaining how the physical geometry of a diode laser determines its performance, the author discusses the three methods that can relax the output-power limits imposed by the gradual or catastrophic degradation of the diode's mirror facets. Attention is given to ways of obtaining high powers at long wavelengths from InGaAsP lasers and the most powerful AlGaAs and InGaAsP devices now available are described. The use of arrays in overcoming present power limits is explained. Applications of high-power lasers in optical-disk recording, fiber-optic distribution networks, laser printers and space communications (satellite-to-satellite) are discussed.

Optical recording by reducing a metal salt complexed to a polymer host

An alternative approach which makes use of a laser to reduce a polymer/complexed metal ion matrix to generate small reflective surfaces is described. The thermal energy provided by the laser promotes an electron transfer from the polymer to the metal ion to form metal. Since the reduction occurs within the thermal profile of the focused laser beam, the reflective area has a diameter close to that of the beam waist. We have formed ∼l-μm-diam reflective areas using a pulsed diode laser. Application of this method to optical disk recording is discussed.

New optical recording material for video disc system

The optical characteristics of Sb2Se3 and Sb2Te3 films are changed due to an amorphous-crystalline phase transition below 200 °C. The respective reflectivity of 400 Å Sb2Se3 and 300 Å Sb2Te3 films, each on a Te reflective layer, is increased from 10% to 30% and from 45% to 65% by laser radiation. Using these new materials, optical disc recording of FM video signals by a diode laser has been demonstrated.

High-power diode lasers for optical recording with operating lifetimes in excess of 10 000 h

Real-time lifetest data are reported which show that single spatial mode CDH-LOC diode lasers can operate stably at 25°C ambient temperature for greater than 10000 h at 40–50 mW output power and 50% duty cycle. This makes CDH-LOC lasers useful for optical disc recording, as well as for a variety of other applications that require high output power in a stable nonastigmatic farfield beam pattern.