bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymer Brushes
Authors: Advincula Rigoberto C. 
Published: July 2004

Abstract

Polymer materials in confined dimensions are of great interest theoretically and experimentally. The investigation of polymer brushes involves the use of surface‐sensitive analytical tools and theoretical models using self‐consistent field theory as well as Monte Carlo simulations. However, of much more recent interest is the investigation of different polymerization mechanisms that can be employed in the so‐called surface initiated polymerization (SIP) or “grafting from” methods where initiators are tethered to surfaces.

Polymer brushes

are

polymer materials prepared and assembled from end‐tethered or SIP systems where the average distance between grafting points can be much smaller than the radius of gyration (
R
g
)

. Macromolecule systems involving polymer blends, block copolymers, complex polymer architectures, and other functional polymers can have intereting properties when confined to surfaces and interfaces. Analogies in bulk or solution do not necessarily hold when applied to the unique anisotropy and dimension of a flat surface or a colloidal particle. It is expected that interesting applications will be derived from the direct tethering of macromolecules in areas such as lubricants, flocculation, membranes, bioapplications, microarrays, lithography, and others.
Ellipsometry
Authors: Collins Robert W. 
Published: July 2004

AbstractEllipsometry is an optical measurement technique that involves generating a monochromatic or quasimonochromatic light beam in a known polarization state and reflecting it from a sample having a planar, specularly reflecting surface. By measuring the polarization state of the reflected beam, the ellipsometric angles (ψ, Δ) can be determined, and upon detailed analysis, these angles yield information about the sample. Such information includes the optical properties, that is, the index of refraction and extinction coefficient, for a bulk sample or the thickness and optical properties for one or more thin films on the sample surface having plane‐parallel interfaces. For an isotropic sample, the angles (ψ, Δ) are defined by tanψexp(iΔ) = rp/rs, whererpandrsare the complex amplitude reflection coefficients for linear p and s polarization states, for which the electric field vibrates parallel and perpendicular to the plane of incidence, respectively. Several variations of the ellipsometry experiment have been developed. In spectroscopic ellipsometry (SE), (ψ, Δ) are measured continuously versus the wavelength of the light beam, and in real‐time ellipsometry (RT‐E), (ψ, Δ) are measured continuously versus time at fixed wavelength. The latter two modes can be combined to yield real‐time SE (RT‐SE), utilizing an instrument with a linear photodiode array for parallel detection at many wavelengths simultaneously. In imaging ellipsometry (IE), (ψ, Δ) are measured over a two‐dimensional (2‐D) area of a nonuniform sample surface using an instrument with a 2‐D charge‐coupled device (CCD) as the detection system. The most widely used instruments for SE and RT‐SE span the spectral range from the ultraviolet (200–300 nm) to the near infrared (800 nm). Over this spectral range, the optical properties deduced from SE provide information on the processes of absorption and dispersion originating from the valence electrons in semiconductors and dielectrics and from the conduction electrons in metals. Specialized SE equipment designed for the infrared range can be more effective for chemical identification of thin films, based on the absorption processes originating from the vibrational modes of chemical bonds.
Laser Physics
Authors: Zayhowski John J. , Kelley Paul L. 
Published: July 2004

AbstractThis article concerns the physics of lasers, including population inversion, pumping processes, stimulated emission, and resonators. Important laser characteristics such as narrow spectral linewidth, high spatial collimation, and ultrashort pulses are discussed. A review is given of several types of laser media, laser dynamics, and modes of laser operation. Methods for control of laser output and practical considerations in laser design are considered. Finally, there is a discussion of nonlinear optical techniques for frequency conversion of laser radiation.
Lasers, Free‐electron
Authors: Pellegrini Claudio , Reiche Sven 
Published: July 2004

AbstractFree‐electron lasers are radiation sources, based on the coherent emission of synchrotron radiation of relativistic electrons within an undulator or wiggler. The resonant radiation wavelength depends on the electron beam energy and can be tuned over the entire spectrum from micrometer to X‐ray radiation. The emission level of free‐electron lasers is several orders of magnitude larger than the emission level of spontaneous synchrotron radiation, because the interaction between the electron beam and the radiation field modulates the beam current with the periodicity of the resonant radiation wavelength. The high brightness and the spectral range of this kind of radiation source allows studying physical and chemical processes on a femtosecond scale with angstrom resolution.
Lasers, Semiconductor
Authors: Ogasawara Nagaatsu , Ito Ryoichi 
Published: July 2004

AbstractFollowing a brief history of semiconductor lasers, this article describes their operation principles in relation to their device structures and materials. Their fundamental operation characteristics, including the static, spectral, and dynamic aspects, are then presented. Finally, the current state of the art in semiconductor laser technology is described by reviewing up‐to‐date devices incorporating new structures and new functions.
Magneto‐optical Devices
Authors: Castera Jean Paul , Suzuki Takao 
Published: July 2004

AbstractThe history of magneto‐optical effects is first introduced. Then the types of magneto‐optical effects are described, which include the varieties of the interactions of electromagnetic waves with magnetization or spins in solids. The physical origin of the magneto‐optical effects is phenomenologically discussed. Both magnetic circular/linear birefringence and dichroism, and Void and Cotton–Mouton effects are discussed. Then, some representatives of magneto‐optical materials of transmission (Faraday effect) and reflection (Kerr) types are described. Finally, the applications of magneto‐optical effects are presented, which include the isolators, circulators, modulators, deflectors, magneto‐optical imaging, field sensors, magneto‐optical sensors, and magneto‐optical recording and microwave waveguides. In particular, a recent development of magneto‐optical recording is summarized, which highlights the various novel methods of increasing recording density.
Modulators and Demodulators, Optical
Authors: LiKamWa Patrick , Yao Shi‐Kay , Young Eddie H. 
Published: July 2004

AbstractModulation is a means of adding a signal information to an energy carrier used for transmission. Demodulation is the process of extracting the signal information from the carrier. Electromagnetic waves have been used extensively as the carrier for radio and television broadcasting as well as wireless and satellite telephony and data communications. Optical waves are electromagnetic waves that are at the much higher end of the frequency spectrum compared to radio frequencies. Therefore, information can be sent at much higher rates using optical carrier waves than using radio waves. In this chapter, the application and the technology of various optical modulators are described. The various forms of modulation formats and demodulation techniques are also discussed.
Optical Communications
Authors: Kogelnik Herwig 
Published: July 2004

AbstractThis article discusses the fundamentals of optical fiber transmission technology and its basic building blocks. It aims to explain the principal characteristics of optical fibers, such as chromatic dispersion, of optical‐fiber amplifiers, including the noise they generate, and of semiconductor lasers. Also included is a discussion of optical receivers and their sensitivities, of nonlinear phenomena in optical‐fibers, of solitons, and of various transmission network architectures such as passive optical networks (PONs).
Optical Computing
Authors: Tanida Jun , Ichioka Yoshiki 
Published: July 2004

Abstract
Optical computing is an area of technology for information processing that utilizes excellent features of light. Beginning with some historical background of this technological field, the concept of optical computing is described with respect to definition, motivation, advantages, targets, and classifications. Then two major categories, analog optical computing and digital optical computing, are used to explain concrete instances of this technology. Analog optical computing includes Fourier image processing, acoustooptical signal processing, optical neural computing, and spatiotemporal information processing. Digital optical computing covers logic gates and circuit constructions, computing paradigms, optical computer architectures, and VLSI photonics. Finally, some comments on potential applications of optical computing are added to suggest effective areas for this technological field.
Interconnections, Optical
Authors: Matsumoto Takao , Trewhella Jean 
Published: July 2004

AbstractAlthough progress has been made in optical interconnections, electrical interconnections continue to dominate most of the hierarchical interconnect layers that comprise computer systems. (The delay in the industry's move to optics is largely due to the continued improvements in electrical links, most notably the addition of equalization schemes [1].) The challenges faced by electrical interconnections [2] are described along with a presentation of the potential benefits optical interconnections afford. Commercial success for optical interconnections has largely been in rack‐to‐rack links, where the distances are great enough to require the low loss advantages of optical transmission. Further work on optical schemes for each layer of interconnection hierarchy, rack to rack, board to board, and intraboard is presented. These schemes can be broken into two general types of guided wave solutions that use fibers or waveguides as transmission media and free‐space solutions, which require only the optical elements. Advantages and examples of links using each type are described. It is shown that free‐space optical interconnections board to board can reduce wiring congestion dramatically over electrical or guided wave approaches, which force all interconnections to pass between the boards through the backplane. The density achievable can be further improved by employing 3D interconnection arrangements which are discussed in the intraboard examples. Optical interconnection will gradually penetrate from the outer levels of the systems to the inner as the technology matures, but all of these interesting possibilities will remain possibilities unless future areas of study include focus on low cost, small size for high density and high reliability of optical interconnections and devices.
Data Storage, Optical
Authors: Milster Tom D. 
Published: July 2004

AbstractIn its most general definition, optical data storage is simply using light as a tool to store and retrieve data. Optical data storage is found in popular consumer products. Compact Discs (CDs), Digital Versatile Discs (DVDs), and MiniDiscs (MDs), are all forms of optical data storage. More advanced forms of optical data storage include high‐speed devices and library products. All optical data storage devices use optical principles to achieve high data density, rugged packaging, reliable information retrieval, and cost‐effective production. There are many forms of optical storage media and many types of optical systems used to scan data. This chapter discusses the basic principles of optical data storage, types of commercial optical media available in 2003, several performance parameters, and some interesting prospects for future systems.
Optical Tomography
Authors: Hillman Elizabeth M. C. 
Published: July 2004

AbstractOptical tomography (OT) is an imaging technique that uses near‐infrared (NIR) and visible light to resolve the internal structure of scattering objects. OT has recently been the focus of much development as a method for imaging living tissue such as the breast and brain. By using NIR light, it is possible to investigate the hemoglobin in bloodin vivo, since hemoglobin is a strong NIR absorber compared to other tissue constituents. Using spectroscopic techniques to extract the oxygenation state of the hemoglobin in tissue can provide information about the functional state of the tissue, allowing detection of tumors, hemorrhages, and other abnormalities. This article introduces the basic concepts of medical OT, giving two detailed examples of instrumental approaches. The physics of light propagation in scattering tissue and the various techniques for tomographic image reconstruction are then detailed, followed by a review of some of the latest novel approaches to OT.
Nonlinear Optics
Authors: Flytzanis Christos 
Published: July 2004

AbstractWe present an unified overview and classification of the main nonlinear optical effects and the underlying nonlinear optical interactions. The physical origin of these effects is analyzed and related to material features and their behavior, their characteristics and efficiency are discussed in terms of the nonlinear propagation equations. Some aspects related to nonlinear optical materials and devices are presented and connections with quantum optics, nonlinear spectroscopy and optoelectronics are stressed.
Physiological Optics
Authors: Jüttner Martin 
Published: July 2004

AbstractPhysiological optics is concerned with the perceptual processes in the eye and its associated neuronal structures in the brain. This article provides an overview of the structure and functionality of the visual system, and of experimental and analytical techniques used to study the principles of visual information processing. First, the anatomy of the eye and the various stages of the optical pathway from the retina to the visual cortex are considered in some detail. The concept of receptive fields is introduced and related to the theoretical framework of spatial‐frequency channels. A range of tools and techniques used in neurophysiological and psychophysical vision research are reviewed and compared. This provides the basis for a detailed discussion of elementary visual sensations, including the perception of brightness, depth, movement, and shape, both with regard to their phenomenology and their neurophysiological foundations. Finally, the role of such elementary sensations for higher‐level visual processes is considered by relating them to current theories of object recognition.
Underwater Optics
Authors: Dolin Lev S. , Levin Iosif M. 
Published: July 2004

Abstract
Four major subjects of the underwater optics are especially important, both for fundamental study of interaction between light and water and for various technical applications. These are (1) inherent optical properties (IOP) of natural waters; (2) propagation of natural and artificial light in the water; (3) optical methods for investigation of natural waters, and (4) underwater imaging. These four items form the main content of the paper and determine the titles of its four main sections.
Section 2 presents the definitions of IOP determining light absorption and scattering in water. Methods of measuring IOP are discussed, and data on spatial and spectral distributions of IOP in natural waters are given. Physical and empirical low‐parametric models considered in the section make it possible to determine the whole set of IOP distributions, based on few measurements. Section 3 deals with the underwater light fields. Methods for solving the radiative transfer equation are considered. The section presents data on the solar irradiance and angular radiance distributions near the sea surface and at the sea depth, as well as on the light field of artificial sources. Optical methods for investigation of natural waters are discussed in Sect. 4. This section is mainly concerned with the problem of remote sensing of phytoplankton, suspended and dissolved matters by measuring the ocean color, with the account of algorithms for atmospheric correction of satellite measurements. Finally, Sect. 5 is devoted to the problem of underwater imaging. The presented theory connects the image parameters, such as modulation transfer function, contrast, signal/noise ratio with the parameters of light sources, detectors, water, and target. Comparison of the sighting range and spatial resolution in water ensured by different underwater imaging systems is given.
Photoemission and Photoelectron Spectra
Authors: Himpsel Franz J. , Lindau Ingolf 
Published: July 2004

AbstractApplications of photoelectron spectroscopy and related techniques are reviewed. They include photoelectric yield spectroscopy, absorption spectroscopy from core levels, photoelectron spectroscopy of core‐level shifts (XPS or ESCA), angle‐resolved photoemission and inverse photoemission, EXAFS, and photoelectron diffraction. These techniques provide information about structure, bonding, and electronic states of atoms, molecules, solids, surfaces, and nanostructures. Advances in detectors and light sources, such as high‐resolution multidetection and synchrotron radiation from undulators, are breaking ground for new applications. Among those are element‐resolved microscopy and high‐resolution spectroscopy of the electronic states relevant to magnetism, superconductivity, and transport properties.
Polarization Optics, Polarimeters and Polarization Spectrometers
Authors: Hermann Gerd 
Published: July 2004

AbstractPolarimeters, employing polarization optics, are well known as highly precise and accurate instruments for determining optically active substances. Even simple manual polarimeters offer high accuracies compared to other analytical methods. Also, more sophisticated devices with half‐shadow adjustment and with quartz‐wedge compensation were already constructed in early times of polarimetry.High improvement of polarimeters has been obtained with modern automated and semiautomated instruments. Until now, polarimetry has been the main analytical standard method for determining sucrose in the sugar and beverage industries and is an important tool for controlling production processes of optically active substances. For obtaining high precision and accuracy, the brightness and monochromaticity of the light source is important.While polarimetry is based on intrinsic optical activity, polarization spectroscopy also measures anisotropies that may be induced into isotropic atomic or molecular species by DC electric or magnetic fields or also by interaction with radiation. Doppler‐free methods of nonlinear polarization spectroscopy yield high spectral resolution and result in the suppression of interferences by extremely close‐lying lines. Polarization spectroscopy based on an applied DC magnetic field, which is also denoted as coherent forward scattering spectroscopy (CFS), allows simultaneous multielement determination in combination with continuum light sources and the measurement over an extremely wide dynamic range.
Remote Sensing
Authors: Zalewski Edward F. 
Published: July 2004

Abstract
Remote Sensing is defined for space‐borne and airborne imaging instruments that use electromagnetic radiation. The historical background for this field of study is presented. The methods of remote sensing are described along with the portions of the electromagnetic spectrum that are utilized. The role of the atmospheric transmission limits and the corrections necessary for optimum accuracy is described. The different types electromagnetic detectors are described along with the image collection systems in which they are used. Modern remote sensing is possible because of the improvement in the accuracy of the radiometric calibration and characterization of the sensors and these methods are briefly described. The objective of remote sensing is the quantitative interpretation of the images, specifically obtaining the data products. Several examples of the basis for some of the data products are presented. Some of the remote sensing systems presently in use are briefly described. The future of remote sensing is described in terms of some of the planned sensors systems and the challenges that must be met in order to understand the Earth and mankind's effect on its climate.
Spectroscopy, Laser
Authors: Inguscio Massimo , Sasso Antonio 
Published: July 2004

Abstract
The high intensity, high spectral purity, and short‐pulse duration of laser sources have opened a new era in laser spectroscopy. Many sophisticated spectroscopic techniques have been developed during the last decades. They have allowed the investigation of the structure of atoms and molecules with great detail, making it possible to test fundamental quantum mechanics theories. Moreover, laser spectroscopy represents a very diffused tool in many other fields. A wide range of applications concern not only free atoms and molecules but also plasma physics and solid‐state physics and many other interdisciplinary fields such as chemistry, biology, and medicine. Laser spectroscopy is till now a very fascinating field of research continuously in evolution: the new techniques of laser cooling have allowed the production of condensates of atoms that represent a new state of the matter only recently explored.
Electrophotographic Copying and Printing (Xerography)
Authors: Hays Dan A. , Ossman Kenneth R. 
Published: July 2004

Abstract
In the electrophotographic process for copying and printing documents, the image content controls the amount of light that selectively discharges a uniformly charged photoreceptor material. The electrostatic image is developed with a charged, pigmented powder that is transferred and bonded to paper with heat and pressure. Over the years, a variety of optical devices and systems have been used as electrophotographic technology has evolved to higher levels of performance and image quality. The earlier copiers utilized a light source and lens optical system to project the document image onto the charged photoreceptor. The imagers for copying use either optics with moving components or flash exposure systems. Electrophotographic printers do not use direct optical imaging but use a digital stream from an external source to generate a printed document. These printers were enabled by advances in digital electronics and light sources that exposed the photoreceptor with a scanning laser beam modulated by digital signals. Alternatively, many electrophotographic printers in recent years utilize a Light Emitting Diode (LED) array and optical lens array to imagewise expose the photoreceptor. An electrophotographic printer combined with an image input scanner becomes a digital copier that provides image editing, multiple copies from a single document scan, and digital image processing for high‐quality color documents. The advances in imaging devices over the last half century have played an important role in the current achievement of high‐quality color electrophotographic documents.