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Masud Mansuripur - One of the best experts on this subject based on the ideXlab platform.

  • the physical principles of magneto Optical Recording
    The Physical Principles of Magneto-optical Recording, 1998
    Co-Authors: Masud Mansuripur
    Abstract:

    From the Publisher: This book covers the physics of magneto-Optical Recording, beginning with first principles and working through to contemporary state-of-the-art topics. Both optics and magnetism are broad subjects, each with many applications in modern technology. This book prepares the reader for advanced work in either field. The first half of the book teaches the theory of diffraction using an original unified approach. It also covers the optics of multilayers (including dielectric, metal, birefringent and magnetic layers), polarization optics, noise in photodetection, and thermal aspects. The second half of the book describes the basics of magnetism and magnetic materials, magneto-static field calculations, domains and domain walls, the mean-field theory of magnetism, magnetization dynamics, the theory of coercivity, and the process of thermomagnetic Recording. In each chapter, throughout the book, after coverage of the fundamentals the author explains the relevance of the topic to magneto-Optical Recording, and examples are given that emphasize this particular connection. Numerous examples based on real-world problems encountered in the engineering design of magneto-Optical media and systems will give the reader valuable insights into the science and technology of Optical Recording. In addition, there are extensive problem sets at the ends of the chapters. This book may be used as an advanced textbook on Optical Recording in both physics and engineering departments, and also as a reference work for scientists and engineers in industrial and academic laboratories.

  • experimental and theoretical investigations of laser induced crystallization and amorphization in phase change Optical Recording media
    Journal of Applied Physics, 1997
    Co-Authors: Chubing Peng, Lu Cheng, Masud Mansuripur
    Abstract:

    We describe the numerical procedure for calculating three-dimensional profiles of temperature in a multilayer stack illuminated by a laser beam, and model the crystallization and amorphization kinetics for phase-change rewritable media. Experimental methods have been used to determine indirectly the probabilities of nucleation and growth for Ge2Sb2Te5 alloy. Some of the fundamental behaviors of phase-change erasable media, such as the crystallization of as-deposited amorphous phase, amorphization of supercooled liquid, and recrystallization of quenched amorphous phase, have been illustrated based on our three-dimensional temperature calculations and the model kinetics. The calculated transient reflectance behavior of as-deposited Ge2Sb2Te5 amorphous films in a single layer and in a quadrilayer stack, as well as the erasure behavior of Ge2Sb2Te5 alloy in a quadrilayer disk are in good agreement with experimental observations.

  • measurement of magnetic anisotropy constant for magneto Optical Recording media a comparison of several techniques
    Journal of Applied Physics, 1993
    Co-Authors: R A Hajjar, T Suzuki, Masud Mansuripur
    Abstract:

    Experimental data of the intrinsic perpendicular magnetic anisotropy energy constant K u are presented for amorphous rare earth‐transition metal (RE‐TM) Tb x (FeCo)1−x and multilayered Co/Pt thin film samples. These data were independently measured using five techniques based on torque magnetometry, the extraordinary Hall effect, and the magneto‐optic Kerr effect. In the Hall effectmeasurement, the external field was applied to the sample in three different ways: fixed at 45° from the film normal; rotating around the sample; and fixed along the in‐plane direction. The results obtained with these techniques agree with each other for the Co/Pt samples. However, we do find systematic differences in the measuredK u for the Tb x (FeCo)1−x samples. For example, K u given by the Hall effect and Kerr effect is always larger (by up to a factor of 3) than that given by torque technique. Another interesting fact is that K u given by the Hall effect technique drops as x approaches the compensation point x c in the TM‐dominant case, but increases as x approaches x c in the RE‐dominant case. These experimental results are explained by taking into account the canting between RE and TM subnetworks.

T. Uruga - One of the best experts on this subject based on the ideXlab platform.

  • Pressure-induced site-selective disordering of Ge2Sb2Te5: A new insight into phase-change Optical Recording
    Physical Review Letters, 2006
    Co-Authors: Alexander Kolobov, Julien Haines, Annie Pradel, Michel Ribes, P. Fons, J. Tominaga, Y. Katayama, Tahar Hammouda, T. Uruga
    Abstract:

    We demonstrate that Ge2Sb2Te5, the material of choice in phase-change Optical Recording (such as DVD-RAM), can be rendered amorphous by the application of hydrostatic pressure. It is argued that this structural change is due to a very strong second-nearest-neighbor Te-Te interaction that determines the long-range order in the metastable cubic phase of Ge2Sb2Te5 and also to the presence of vacancies. This newly discovered phenomenon suggests that pressure is an important factor for the formation of the amorphous phase which opens new insight into the mechanism of phase-change Optical Recording.

Matthew Donnelly - One of the best experts on this subject based on the ideXlab platform.

  • high yield passive si photodiode array towards Optical neural Recording
    IEEE Electron Device Letters, 2018
    Co-Authors: Dacheng Mao, John Morley, Ziqi Zhang, Matthew Donnelly
    Abstract:

    Emerging fluorescent protein-based sensors allow researchers to monitor neural activities via Optical Recording of the fluorescence signals. This Optical method is able to monitor multiple cell signals with ease in identifying individual cells in dense neurocircuitry. To this end, we demonstrate a high-yield passive Si photodiode array, aiming to establish a miniaturized Optical Recording device toward in-vivo use. Our fabricated array features a high yield (>90%), low detection limit (32 $\mu {\text{W}}$ /cm2), and high speed (1000 frames per second for scanning up to 100 pixels). Using a fast I–V measurement setup, we examined the device performance in terms of detection limit and speed. A mapping of the light intensity on the entire array manifests its promise as an on-chip fluorescence imager for Optical neural Recording. The array routinely consumes sub- $10~\mu {\text{W}}$ power, which is suitable for chronic in vivo use.

  • high yield passive si photodiode array towards Optical neural Recording
    International Electron Devices Meeting, 2017
    Co-Authors: Dacheng Mao, John Morley, Ziqi Zhang, Matthew Donnelly
    Abstract:

    Fluorescent protein sensors, once expressed in neurons, can report cell activity by Optical Recording of the fluorescence of the sensors. Here we demonstrate a high yield, passive Si photodiode array, aiming to establish a miniaturized Optical Recording device for in-vivo use. Our fabricated array features high yield (>90%), high sensitivity (down to 32 μW/cm2), and high speed (1000 frame per second by scanning over up to 100 pixels). Using a fast-IV measurement setup, we examined the array performance in terms of the responsivity, speed, and signal to noise ratio. The array routinely consumes sub-10 μW power, suitable for chronic in vivo use.

Ferry Zijp - One of the best experts on this subject based on the ideXlab platform.

Guofu Zhou - One of the best experts on this subject based on the ideXlab platform.

  • materials aspects in phase change Optical Recording
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2001
    Co-Authors: Guofu Zhou
    Abstract:

    Abstract Phase change Recording materials used in reversible Optical Recording disks are briefly reviewed with focus on Ge–Sb–Te and Ag–In–Sb–Te materials. Methods that lead to a high crystallization rate of the Ge–Sb–Te Recording layer are discussed. The role of Recording layer composition, its thickness and interface layers, is especially emphasized. It is demonstrated that the methods used for increasing the crystallization rate of Ge–Sb–Te materials usually lead to opposite results in Ag–In–Sb–Te because of their different crystallization mechanisms: nucleation-driven vs growth-driven crystallization processes. Using Ge–Sb–Te and Ag–In–Sb–Te as example materials, a method is introduced for distinguishing crystallization mechanisms of an amorphous material.

  • high performance media for phase change Optical Recording
    Japanese Journal of Applied Physics, 1999
    Co-Authors: Guofu Zhou, Bernardus Antonius Joha Jacobs
    Abstract:

    We discuss various mechanisms that lead to a high crystallization rate of the Recording layer in a phase change disk. The role of interface layers, Recording layer composition and its thickness is especially emphasized. Disks with a data bit rate beyond 40 Mbit/s have been realized.