Laser Beam Recorder Research Articles

Doubly Photopolymerized Holographic Sensors.

Holographic sensors are two-dimensional (2D) photonic crystals that diffract narrow-band light in the visible spectrum to quantify analytes in aqueous solutions. Here, a holographic fabrication setup was developed to produce holographic sensors through a doubly polymerization system of a poly-2-hydroxyethyl methacrylate hydrogel film using a pulsed Nd:YAG laser (λ = 355 nm, 5 ns, 100 mJ). Wavelength shifts of holographic Bragg peak in response to alcohol species (0-100 vol %) were characterized. Diffraction spectra showed that the holographic sensors could be used for short-chain alcohols at concentrations up to 60 vol %. The reversibility of the sensor was demonstrated, exhibiting a response time of 7.5 min for signal saturation. After 30 cycles, the Bragg peak and color remained the same in both 20 and 60 vol %. The fabrication parameters were simulated in MATLAB using a 2D finite-difference time-domain algorithm to model the interference pattern and energy flux profile of laser beam recording in the hydrogel medium. This work demonstrates a particle-free holographic sensor that offers continuous, reversible, and rapid colorimetric readouts for the real-time quantification of alcohols.

Використання халькогенідних склоподібних напівпровідників для створення мікро- та нанорозмірних структур

The results on the analysis of methods for the formation of nanoscale elements on thin films of chalcogenide glassy semiconductors and their application to create optical diffraction elements are presented. When creating micro- and nanoelements of optoelectronic devices, micro / nanoelectromechanical systems (MEMS/NEMS) and diffractive optical elements, chalcogenide glassy semiconductors (CGS) can be effectively used. The use of CGS is mainly based on their sensitivity to various types of radiation, which cause structural changes in them and transparency for infrared light. Numerous studies have been carried out aimed at studying the processes of formation of nanostructures on CGS films. A number of photoinduced changes are observed in CGS, which are associated with structural transformations, phase transitions, defect formation, and atom diffusion. It is of interest to determine the technologies for the formation of micro- and nanoscale structures on CGS films that can be used to create diffractive optical elements for optoelectronic devices. Increasing the resolution of recording media based on vitreous chalcogenide semiconductors can be achieved by choosing recording modes and glass compositions, in which the nonlinearity of the exposure characteristics of photosensitive material is most pronounced, as well as the introduction of noble metal nanoparticles for excitation of precious metals for excitation. A promising area of application of chalcogenide glassy semiconductors can be direct laser recording of diffractive optical elements at upgraded laser beam recorder of master disks. The unique properties of chalcogenide glassy semiconductors allow the formation of microrelief images without selective chemical etching due to the irradiation of thin films with rays of different polarization. Fig.: 8. Refs: 41 titles.

Прямий лазерний запис мікрорельєфних структур в халькогенідних склах лазерним променевим записувачем мастер-дисків

Methods to create microrelief phase elements for diffractive optics and ophthalmology were analyzed. Direct laser writing, by a laser beam recorder used for master discs is an effective method for the formation of flat microrelief phase elements on thin films of chalcogenide semiconductors, where photo-structural transformations occur under the action of laser radiation.

Определение температуропроводности материалов методом нестационарного точечного нагрева

Express thermographic method for measuring thermal diffusivity of thin flat objects is described in the paper. It could be considered as modification or a branch of laser flash method, however it does not require sample cutting or two side access to the object. The method comprises step-like heating of the small area (~ 0.1 mm2) at the object surface by focused laser beam and continuous recording temperature distribution at the surface by thermal camera. Developed data processing technique does not require information about absolute temperatures or absorbed energy for determination of thermal diffusivity coefficient.

Inorganic Resist Film for Submicron Structure Fabrication

The current study employs an inexpensive thermal lithography technique to fabricate submicron size structures for applications in blu-ray optical disks and other optoelectronics. A heat buffer layer and an inorganic resist layer of Ge- Sb-Sn-O are sequentially deposited on a pre-grooved polycarbonate substrate. Laser irradiation is then carried out by a laser beam recording system with wavelength of 405nm and numerical aperture of 0.65. The size of features can be controlled by regulating laser power and development parameters while taking resist thickness and heat removal of thin film structure into consideration. Minimum feature size of 175nm in width and 107nm in depth is obtained. It has overcome the optical diffraction limit of irradiation laser spot. Furthermore, dot patterns can be prepared using laser pulse strategy.

Improvement of Thermal Interference for High-Density Thermal Recording Mastering

We optimized the silicon master structure with the dielectric material as the recording material of the thermal recording. We confirmed that a 48-nm-long pit was able to be recorded with a laser of 405 nm wavelength. As a result of that, we could make a 250 gigabyte (GB) data capacity master with a conventional laser beam recorder (LBR). 75 and 100 GB discs with a photopolymer cover film made by the same method were able to be read with a solid immersion lens (SIL)-equipped tester. The 75 and 100 GB disc jitter values were 6 and 10%, respectively. We also confirmed that a 37-nm-long pit could be formed with the SIL-equipped tester as the recording machine of the thermal recording.

Thermal Recording for High-Density Optical Disc Mastering

Thermal recording using a dielectric as a recording material was examined to make a high-density optical disc master. We confirmed that a pit of 53 nm length was able to be recorded with a laser of 405 nm wavelength. As a result we could make a master with a 200 gigabyte (GB) data capacity with a conventional laser beam recorder (LBR). A 100 GB disc made by the same method was able to be read with a tester equipped with a solid immersion lens (SIL) and the measured jitter value was 9.9%.

Spin Coatable Inorganic Resist for High Density Disk Mastering Process Application

Along with the development of high definition televisions (HD-TVs), some high density optical discs are demanded to have a capacity of up to 25 Gbytes on a single layer at a single surface. The capacity on single layer may even reach up to 100 Gbytes in the near future, which requires the size of recording to be minimized to less than 100 nm. In this study, ultra high resolution patterns (<100 nm) formation by conventional laser beam recorder using the inorganic spin-coatable photoresist and without additional development or etching process is demonstrated. The recording spot size of laser beam recorder (LBR) can be reduced effectively by using this spin coatable inorganic photoresist.

Phase-Transition Mastering of High-Density Optical Media

A new phase-transition mastering (PTM) process was developed for Blu-ray Disc read-only memory (BD-ROM) mastering. Results obtained with both a 266 and 405 nm laser beam recorder (LBR) are discussed in this paper. The feasibility of BD-ROM mastering was successfully demonstrated on both LBRs. With the insight that 25 Gbytes BD-ROM can be mastered with a 405 nm wavelength LBR, the availability of the 266 nm wavelength LBR opened the route to explore PTM of near-field data densities. First experiments indicate that the PTM process is also suitable for mastering data densities beyond 25 Gbytes data density.

High-Density Read-Only-Memory Disc Mastering Using Direct-Focus Laser Beam Recorder

The authors have developed a novel laser beam mastering apparatus using a deep-UV (DUV) laser for a high-density optical disc. A direct focusing mechanism, where the recording beam itself is also used for focusing, is applied in the laser beam recorder (LBR). The mechanism solves the focus depth issue and provides stable focusing. The evaluation results for the 23.3-Gbytes-capacity read-only-memory (ROM) disc revealed that uniform recording can be realized. Jitter variations in the tangential and radial directions were suppressed to less than 0.2% and 0.07%, respectively. A low residual tracking error signal was also attained. The measurement results for the 25-Gbyte-capacity disc show reasonable jitter not only for a resist/glass disc, but also for an injection-molded disc. The tilt margin of the disc confirmed that the disc was practical for application in the market. Furthermore, the evaluation of the 27 GByte disc indicated the possibility of higher density ROM disc mastering.

Manufacture of 27 GB Read-Only-Memory Disc Using Deep-UV Beam Recorder with Two-Dimensional Optical Compensation

A novel mastering method using a deep-UV laser beam recorder (LBR) with two-dimensional optical compensation has been proposed. Using this technique, uniform fine pits can be created. The result reveals that a 27 GB read-only-memory (ROM) disc can be realized. The bottom jitter with a limit equalizer was 7.5%.

Improvements of Resolution and Surface Roughness using Alkaline Treatment of Photoresist Surface in High-Density Optical Disk Mastering

In the next-generation optical disk using blue laser diodes, the track pitch will be reduced to 0.3 µm, that is about half of the track pitch of digital versatile disks. To realize such high-density optical disks, it is important to develop a high-density optical disk mastering technique. In particular, in this mastering technique, two major improvements, resolution improvement and surface roughness reduction, are required. In this work, we fabricate grooves with track pitches of 0.28–0.40 µm land/groove using an ultraviolet laser beam recorder, and investigate the influences of an alkaline treatment of positive photoresist surface on the resolution and the surface roughness of the grooves. We confirm experimentally that the alkaline treatment is effective for the resolution improvement and the roughness reductions of the surface and sidewall. We also show that these effects are attributed to the contrast enhancement and the decrease of photoresist film thickness loss.

Master Recording for High-Density Disk Using 248 nm Laser Beam Recorder

A deep ultra-violet (UV) laser beam recorder (LBR) with 248 nm wavelength was developed to realize a high-density disk. The characteristics of the LBR are the wavelength and the multifunctional design. Among the possible laser wavelengths, 248 nm is the shortest wavelength applicable with Novolac photoresist, and the LBR has both modulation and deflection functions to support various formats flexibly. It was confirmed that the LBR performance was such that a groove of even 0.26 µm track pitch could be recorded, and the shape was observed with a scanning electron microscope (SEM). The disk with a groove of 0.32 µm track pitch recorded by the LBR had a practical deviation in the tracking error signal, and the addressed disk with phase-change material and a 0.1-mm-thick cover layer showed the stable reproduction of the address and a practical jitter at the equivalent density for achieving 25 GB capacity at 120 mm in diameter, on the condition of having a pick-up head with a wavelength of 400 nm and an NA of 0.85.

High Density Mastering Using Electron Beam

A mastering system for the next-generation digital versatile disk (DVD) is required to have a higher resolution compared with the conventional mastering systems. We have developed an electron beam mastering machine which features a thermal field emitter and a vacuum sealed air spindle motor. Beam displacement caused by magnetic fluctuation with spindle rotation was about 60 nm(p-p) in both the radial and tangential directions. Considering the servo gain of a read-out system, it has little influence on the read-out signal in terms of tracking errors and jitters. The disk performance was evaluated by recording either the 8/16 modulation signal or a groove on the disk. The electron beam recording showed better jitter values from the disk playback than those from a laser beam recorder. The deviation of track pitch was 44 nm(p-p). We also confirmed the high density recording with a capacity reaching 30 GB.

High-Density Optical Disc Mastering Using Photobleachable Dye

The authors earlier developed a UV laser beam recorder (UV-LBR) and the mastering process for a high-density optical disc. Although it has sufficient resolution for the current digital versatile disc (DVD), the available resolution is not sufficient for the next generation DVD. Therefore, the authors have developed a new mastering process that can extend the resolution limit of the UV-LBR to realize the next generation DVD. It uses photobleachable dye (PBD) coated over a photoresist layer. In this paper, the effectiveness of the new multilayer mastering process is discussed, especially the writing ability of random data using 8/16-modulation. From the results of the experiments, the authors confirmed that the new process, which consists of a multilayer using PBD, has an advantage over the conventional process in the high-density recording, for a recording capacity of 13 Gbytes or greater.

光ディスク 原盤露光装置の精密機構

光ディスク 原盤露光装置の精密機構

High Recording Density Optical Disc Mastering

Aiming at obtaining a high CNR (carrier-to-noise ratio) and four times higher recording density than that of the conventional Laser Disc, we have developed a mastering process for a Laser Beam Recorder utilizing an ultraviolet laser. A photoresist claiming high resolution and high CNR has been screened out from the photoresists available on the market. By the improvement of the photoactive component in the photoresist, a CNR of 61.5 dB was obtained in the case of the 4-times higher density.

HDTV Laser-Beam Recording on 35mm Color Film and its Application to Electro-Cinematography

A laser-beam recorder has been developed by NHK which transfers high-definition television signals to 35mm motion-picture film. This device can expose slow and fine-grain 35mm color film, such as color print film or color internegative film, so that the picture quality of recorded film is superior to that of the conventional recorder. Results of various recording experiments have shown that laser-recording technology can be applied to electro-cinematography, video printing, and photography by utilizing a high-definition television system.

Description Of A Dry Film Tactical Laser Beam Recorder

This article describes a laser beam image recorder, which has been designed and fielded for a minimum amount of flexibility for the operator and a maximum amount of control by a remote sensor minimizing the operator duties and requirements. It is also designed for the shelter environment of a tactical and field operation, where the environment is not so benign. With the advent of recent electronic sensors, the capability for data linking information directly to ground with immediate image production is now feasible. The laser beam recorder, which RCA chose to call the Tactical Laser Beam Recorder because of its application, has been designed to meet three general types of applications which are somewhat similar. They are systems with electronic sensors and data link capability, where images can be immediately produced, all in high resolution. The information from an Air Force remote sensor system is directed to the Tactical Laser II earn Recorder which records a latent image, immediately processes the film on a continuous in-line basis, and slides the film automatically across the photo-interpreter's tables. Simultaneously, a tape recorder records the information in the airborne reconnaissance plane in the event that a data link is not maintained,

Design Considerations For A Flexible High-Resolution Film Recording System

The High Resolution Film Recording System (HRFRS), recently delivered to NASA/Goddard Space Flight Center by RCA, is uniquely characterized by full flexibility in: resolution (1,000 to 20,000 pixels/scan), line rate (15-350' lines/sec), data rate (0.5 to 20 Mbit/sec), optical spot size (10 itaM to 200 pm), pixel aspect ratio (0.5 to 2.0), and frame aspect ratio (0.5 to 2.0). This flexibility is designed to accommodate the specific characteristics of all NASA's satellite, imaging sensors of the 1970s and 1980s. RCA renamed this system Operation Laser Beam Recorder (OLBR) to reflect the production environment in which this versatile, high performance image recorder must operate. Design tech niques and objectives are presented which meet the required flexibilities while maintaining simplicity of design, repeatability, quality of performance, and operability in an image production environment. Human factors, careful partitioning of subsystems, and innovative design techniques are successfully employed to yield a versatile film recording system with a minimum of operational complexity..