Showing papers in "Progress in Optics in 2010"

Propagation-Invariant Optical Fields

Abstract: The first article by Turunen and Friberg deals with a class of fields with propagation-invariant properties such as the optical intensity distribution. Coherent and partially coherent stationary and pulsed solutions are treated in view of scalar and electromagnetic approaches. Approximations of ideal propagation-invariant fields and methods for their generation are discussed. Finally, some application areas are covered.

Vacuum-Induced Processes in Multilevel Atoms

Abstract: Publisher Summary Atoms commonly do not act as isolated objects, but rather are open quantum systems, as they interact with the environment Typically, this environment is formed by the electromagnetic vacuum field The interaction of atoms with the environment modifies the atomic dynamics, with spontaneous emission as the most obvious example Spontaneous emission is generally recognized as incoherent process, which leads to decoherence and, therefore, forms a major limitation for many schemes of current theoretical and experimental interest But vacuum-induced processes can also generate coherent time evolution These coherences can be interpreted as arising from vacuum-induced transitions between different atomic states The situation becomes even more interesting if different atoms can exchange energy via the vacuum Such dipole–dipole interactions induce both coherent and incoherent atomic dynamics, leading to significant deviations from the single-atom properties Finally, a complex interplay of vacuum-induced interatomic and intraatomic dynamics may arise if several multilevel atoms are considered These vacuum-induced processes form the basis for a large number of applications, for which the vacuum-induced dynamics can be favorable, perturbing, or even both Most applications can be improved, if the vacuum-induced processes can be modified or even controlled Thus, a profound understanding of vacuum-induced processes is desirable Motivated by this, this chapter discusses vacuum-induced processes in multilevel atoms

The structure of partially coherent fields

Abstract: Publisher Summary The general framework of optical coherence theory is now well established and has been described in numerous publications. This chapter provides an overview of recent advances, both theoretical and experimental, that have been made in a number of areas of classical optical coherence. These advances have been spurred on by the introduction of the space-frequency representation of partially coherent fields, and an increased emphasis on the spatial coherence properties of wave fields. The fundamental experiment to measure spatial coherence is Young's double-slit experiment. A number of important optical processes are influenced by the coherence properties of the wave field. Results relating to the propagation of partially coherent wavefields highlight some of the significant results relating to optical beams. The influence of coherence on focusing is summarized and reviewed, along with the scattering of partially coherent wave fields and its relation to inverse scattering problems is discussed. It has been shown that spatial correlation functions have interesting topological properties associated with their phase singularities; these properties and the relevant literature are discussed. The coherent mode representation and its applications are described and several techniques for the numerical simulation of wave fields with a prescribed statistical behavior are explained.

Optical Quantum Computation

Abstract: We review the field of Optical Quantum Computation, considering the various implementations that have been proposed and the experimental progress that has been made toward realizing them We examine both linear and nonlinear approaches and both particle and field encodings In particular we discuss the prospects for large scale optical quantum computing in terms of the most promising physical architectures and the technical requirements for realizing them

Chapter 4 – Adaptive Lens

Abstract: Publisher Summary Adaptive or varifocal lenses with variable focusing powers have attracted much attention because of their wide applications in vision care, consumer electronics such as digital cameras, aberration correction, optical interconnects, and three-dimensional biomedical imaging. The focal power of an optical system is usually changed by nonlinear movement of lenses with spherical or cylindrical powers along the optical axis and such a system consists of several lens components. A lot of efforts have been devoted to the research in adaptive lens. Recent advances in this field have been reviewed in this chapter. For liquid crystal lens, refractive and diffractive LC lenses based on discrete electrodes, hole-patterned electrodes, modal control electrode, hybrid alignment, and polymer/LC materials have been discussed in detail. For liquid lenses, lenses based on mechanic pressure, electrowetting effect, dielectric effect, and hydrogel and thermal effect have been reviewed. Examples of applications in vision care, aberration compensation, zoom lens, and optical tweezers have been discussed.

The Mathematical Theory of Laser Beam-Splitting Gratings

Abstract: We review the mathematical theory of laser beam splitting gratings. We discuss the theory of one and two dimensional gratings, for both continuous and Dammann gratings.

Polarization and Coherence Optics: Historical Perspective, Status, and Future Directions

Abstract: For polarization and coherence optics, the chain of thought extends from the late 1660s to nowadays. We describe some of the milestones, of the past three and a half centuries, along the road towards increased understanding of polarization optics. As we shall see, the nascent germ of many novel ideas in polarization optics can be traced back directly or indirectly to Stokes, and Poincare and other physicists from times long gone by. The story is divided into four main steps: from Bartholinus (1669) to Stokes (1852) polarization is a geometric property of light; from Stokes (1852) to Poincare (1892) : polarization is an electromagnetic property of light; from Poincare (1892) to Wolf (1954)ˆˆa0: polarization is a statistical property of light; and nowˆˆa0: geometric-algebra is back. In so doing, we hope to give the reader a taste of the conceptual issues suggesting that geometric-algebra provides a unifying conceptual framework from which to view different descriptions of the polarization states.

Manipulating Light States by Single-Photon Addition and Subtraction

Abstract: Publisher Summary The fundamental quantum operations of single-photon addition and subtraction are promising tools for completely engineering quantum light states and testing the principles of quantum physics. The additional capability of combining such basic operations in sequences and arbitrary superpositions has further extended the range of possible light state manipulations. Quantum information protocols like quantum teleportation, quantum cloning, and quantum cryptography, mainly devised for spin-1/2 systems (especially polarization-entangled photons) can also be efficiently realized in the continuous-variable (CV) regime. This chapter discusses single-photon operators for manipulating quantum information and the unified treatment of experimental single-photon addition and subtraction implementations. Single-photon addition is a very attractive tool for generating quantum states with different degrees of nonclassicality and explore the boundary between classical and quantum behavior. It may also be used to put to a stringent test different experimental criterion to measure the nonclassical character of a state. Single-photon subtraction is described, followed by a look at sequences and superpositions of single-photon operators. Recent experimental demonstrations have opened new exciting perspectives in the accurate generation and manipulation of photonic states and will certainly provide an important basis toward the application of quantum physics to future technologies.

Science and Engineering of Photonic Crystals

Abstract: The history of photonic crystals started with the pursuit of the complete photonic band gap. This was achieved in the microwave frequency range by Yablonovitch, Gmitter, and Leung in 1991. Although some important applications of the photonic band gap such as the creation of highly localized electromagnetic modes and waveguides could be realized in the microwave range, others such as the suppression of spontaneous emission of photons and enhanced optical nonlinearities required the downsizing of photonic crystals to optical wavelengths. Researchers made tremendous efforts and eventually succeeded in this. This article describes the essence of this history and the state of the art of photonic crystals.

Theoretical Tools for Quantum Optics in Structured Media

Abstract: In this work we review modern methods and theoretical tools for description of a quantum system interaction with reservoirs. A particular attention is given to electromagnetic field reservoirs of structured media, such as photonic crystals. We describe ways to model a system-reservoir interaction under conditions when the reservoir correlation time cannot be assumed negligibly small, and non-Markovian effects are significant. We address ways to obtain exact and approximate solutions for the complete system plus reservoir problem, and also methods to obtain and solve master equations for non-Markovian problems.

Optical Pulse Propagation in Biological Media: Theory and Numerical Methods

Abstract: Publisher Summary Different versions of the “Tricorder” device used in Star-Trek science fiction series can noninvasively scan any physical, chemical, or biological entity and cure ailments by hovering over their bodies. Recent advances in ultra-sound and electromagnetics (including optics) could make “Tricorder” a reality. Increasingly, novel innovative ways of using light for clinical applications are developed by researchers all around the world. All these developments rely on having a detailed understanding of light propagation through tissue. Such understanding can only be gained by creating sufficiently accurate models that can capture the essence of light interaction with biological media. This chapter covers the transient characteristics of optical fields propagating through biological media at sufficiently low power levels, which do not induce physical or chemical changes in the material. It specifically looks at short, low-intensity pulses interacting with biological media and discards any light-induced permanent changes (tissue damage and ablation) or secondary emission processes (fluorescence and phosphorescence). A review of the basic features of light scattering from biological media is presented that points out some specific features and provides pointers to literature for specific details. The quantitative aspects of light propagation through tissue are covered by a discussion of the general structure of the transient photon transport equation and related quantities. Various ways of solving the transient photon transport equation is described and the strengths and weakness of each method is highlighted.