Sample records for nonlinear geometric optics

  1. Fully controllable adiabatic geometric phase in nonlinear optics. (United States)

    Karnieli, Aviv; Arie, Ady


    We propose and analyze a new way for obtaining an adiabatic geometric phase for light, via the sum-frequency-generation nonlinear process. The state of light is represented by the complex amplitudes at two different optical frequencies, coupled by the second order nonlinearity of the medium. The dynamics of this system is then shown to be equivalent to that of a spin-1/2 particle in a magnetic field, which in turn can be rotated adiabatically on the Bloch sphere. When the input wave itself is an eigenstate of the magnetic field equivalent, the geometric phase is manifested as a pure phase factor. Two adiabatic rotation schemes, based on specific modulations of the quasi-phase-matching poling parameters, are discussed. In the first, the geometric phase is shown to be sensitive to the pump intensity variations, as a result of the Bloch sphere deformation. The second can be utilized for the realization of nonlinear-optics-based geometric phase plates. Moreover, non-closed adiabatic trajectories are investigated, which are expected to provide a robust and broadband geometric wavefront shaping in the sum frequency.

  2. Nonlinear unitary transformations of space-variant polarized light fields from self-induced geometric-phase optical elements (United States)

    Kravets, Nina; Brasselet, Etienne


    We propose to couple the optical orientational nonlinearities of liquid crystals with their ability to self-organize to tailor them to control space-variant-polarized optical fields in a nonlinear manner. Experimental demonstration is made using a liquid crystal light valve that behaves like a light-driven geometric phase optical element. We also unveil two original nonlinear optical processes, namely self-induced separability and nonseparability. These results contribute to the advancement of nonlinear singular optics that is still in its infancy despite 25 years of effort, which may foster the development of nonlinear protocols to manipulate high-dimensional optical information both in the classical and quantum regimes.

  3. Numerical nonlinear complex geometrical optics algorithm for the 3D Calderón problem

    DEFF Research Database (Denmark)

    Delbary, Fabrice; Knudsen, Kim


    computer implementation of the full nonlinear algorithm is given. First a boundary integral equation is solved by a Nystrom method for the traces of the complex geometrical optics solutions, second the scattering transform is computed and inverted using fast Fourier transform, and finally a boundary value...... to the generalized Laplace equation. The 3D problem was solved in theory in late 1980s using complex geometrical optics solutions and a scattering transform. Several approximations to the reconstruction method have been suggested and implemented numerically in the literature, but here, for the first time, a complete...... to the simpler approximations. In addition, convergence of the numerical solution towards the exact solution of the boundary integral equation is proved....

  4. Linear and nonlinear optical properties of multilayered spherical quantum dots: Effects of geometrical size, hydrogenic impurity, hydrostatic pressure and temperature

    International Nuclear Information System (INIS)

    Karimi, M.J.; Rezaei, G.; Nazari, M.


    Based on the effective mass and parabolic one band approximations, simultaneous effects of the geometrical size, hydrogenic impurity, hydrostatic pressure, and temperature on the intersubband optical absorption coefficients and refractive index changes in multilayered spherical quantum dots are studied. Energy eigenvalues and eigenvectors are calculated using the fourth-order Runge–Kutta method and optical properties are obtained using the compact density matrix approach. The results indicate that the hydrogenic impurity, hydrostatic pressure, temperature and geometrical parameters such as the well and barrier widths have a great influence on the linear, the third-order nonlinear and the total optical absorption coefficients and refractive index changes. -- Highlights: • Hydrogenic impurity effects on the optical properties of a MSQD are investigated. • Hydrostatic pressure and temperature effects are also studied. • Hydrogenic impurity has a great influence on the linear and nonlinear ACs and RICs. • Hydrostatic pressure and temperature change the linear and nonlinear ACs and RICs

  5. Multiphase Weakly Nonlinear Geometric Optics for Schrödinger Equations

    KAUST Repository

    Carles, Rémi


    We describe and rigorously justify the nonlinear interaction of highly oscillatory waves in nonlinear Schrödinger equations, posed on Euclidean space or on the torus. Our scaling corresponds to a weakly nonlinear regime where the nonlinearity affects the leading order amplitude of the solution, but does not alter the rapid oscillations. We consider initial states which are superpositions of slowly modulated plane waves, and use the framework of Wiener algebras. A detailed analysis of the corresponding nonlinear wave mixing phenomena is given, including a geometric interpretation of the resonance structure for cubic nonlinearities. As an application, we recover and extend some instability results for the nonlinear Schrödinger equation on the torus in negative order Sobolev spaces. © 2010 Society for Industrial and Applied Mathematics.

  6. Nonlinear optics

    CERN Document Server

    Bloembergen, Nicolaas


    Nicolaas Bloembergen, recipient of the Nobel Prize for Physics (1981), wrote Nonlinear Optics in 1964, when the field of nonlinear optics was only three years old. The available literature has since grown by at least three orders of magnitude.The vitality of Nonlinear Optics is evident from the still-growing number of scientists and engineers engaged in the study of new nonlinear phenomena and in the development of new nonlinear devices in the field of opto-electronics. This monograph should be helpful in providing a historical introduction and a general background of basic ideas both for expe

  7. Nonlinear optics

    CERN Document Server

    Boyd, Robert W


    Nonlinear Optics is an advanced textbook for courses dealing with nonlinear optics, quantum electronics, laser physics, contemporary and quantum optics, and electrooptics. Its pedagogical emphasis is on fundamentals rather than particular, transitory applications. As a result, this textbook will have lasting appeal to a wide audience of electrical engineering, physics, and optics students, as well as those in related fields such as materials science and chemistry.Key Features* The origin of optical nonlinearities, including dependence on the polarization of light* A detailed treatment of the q

  8. Discriminating cascading processes in nonlinear optics: A QED analysis based on their molecular and geometric origin (United States)

    Bennett, Kochise; Chernyak, Vladimir Y.; Mukamel, Shaul


    The nonlinear optical response of a system of molecules often contains contributions whereby the products of lower-order processes in two separate molecules give signals that appear on top of a genuine direct higher-order process with a single molecule. These many-body contributions are known as cascading and complicate the interpretation of multidimensional stimulated Raman and other nonlinear signals. In a quantum electrodynamic treatment, these cascading processes arise from second-order expansion in the molecular coupling to vacuum modes of the radiation field, i.e., single-photon exchange between molecules, which also gives rise to other collective effects. We predict the relative phase of the direct and cascading nonlinear signals and its dependence on the microscopic dynamics as well as the sample geometry. This phase may be used to identify experimental conditions for distinguishing the direct and cascading signals by their phase. Higher-order cascading processes involving the exchange of several photons between more than two molecules are discussed.

  9. Geometrical optical illusionists. (United States)

    Wade, Nicholas J


    Geometrical optical illusions were given this title by Oppel in 1855. Variants on such small distortions of visual space were illustrated thereafter, many of which bear the names of those who first described them. Some original forms of the geometrical optical illusions are shown together with 'perceptual portraits' of those who described them. These include: Roget, Chevreul, Fick, Zöllner, Poggendorff, Hering, Kundt, Delboeuf Mach, Helmholtz, Hermann, von Bezold, Müller-Lyer, Lipps, Thiéry, Wundt, Münsterberg, Ebbinghaus, Titchener, Ponzo, Luckiesh, Sander, Ehrenstein, Gregory, Heard, White, Shepard, and. Lingelbach. The illusions are grouped under the headings of orientation, size, the combination of size and orientation, and contrast. Early theories of illusions, before geometrical optical illusions were so named, are mentioned briefly.

  10. Determination of geometrical, spectroscopic, thermal and nonlinear optical parameters of (+)-Varitriol by DFT/ab initio calculations. (United States)

    Vasantha Kumar, V; Nagabhushanam, M; Laxmikanth Rao, J


    Theoretical studies have been carried out on (+)-Varitriol using both the B3LYP/6-311+G and HF/6-311+G methods. The vibrational spectra of the title molecule have been recorded in solid state with FT-IR and Micro-Raman spectrometry. The calculated geometrical parameters of the title molecule, like bond length, bond angle and dihedral angles have been compared with the experimental data. The spectral frequencies have been calculated theoretically using both the above mentioned methods and are compared with the observed spectra. The complete vibrational assignments of wavenumbers have been made on the basis of potential energy distribution (PED). From this analysis, it is seen that the vibrational frequencies obtained from B3LYP method are in good agreement with the experiment, when compared to HF method. Nonlinear optical properties like dipole moment, hyperpolarizabilities and thermal properties like rotational constants, zero point vibrational energies are calculated. The effect of temperature on various thermodynamic properties have been calculated and reported. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Advances in nonlinear optics

    CERN Document Server

    Chen, Xianfeng; Zeng, Heping; Guo, Qi; She, Weilong


    This book presents an overview of the state of the art of nonlinear optics from weak light nonlinear optics, ultrafast nonlinear optics to electro-optical theory and applications. Topics range from the fundamental studies of the interaction between matter and radiation to the development of devices, components, and systems of tremendous commercial interest for widespread applications in optical telecommunications, medicine, and biotechnology.

  12. Field guide to geometrical optics

    CERN Document Server

    Greivenkamp, John E


    This Field Guide derives from the treatment of geometrical optics that has evolved from both the undergraduate and graduate programs at the Optical Sciences Center at the University of Arizona. The development is both rigorous and complete, and it features a consistent notation and sign convention. This volume covers Gaussian imagery, paraxial optics, first-order optical system design, system examples, illumination, chromatic effects, and an introduction to aberrations. The appendices provide supplemental material on radiometry and photometry, the human eye, and several other topics.

  13. Nonlinear Optics and Applications (United States)

    Abdeldayem, Hossin A. (Editor); Frazier, Donald O. (Editor)


    Nonlinear optics is the result of laser beam interaction with materials and started with the advent of lasers in the early 1960s. The field is growing daily and plays a major role in emerging photonic technology. Nonlinear optics play a major role in many of the optical applications such as optical signal processing, optical computers, ultrafast switches, ultra-short pulsed lasers, sensors, laser amplifiers, and many others. This special review volume on Nonlinear Optics and Applications is intended for those who want to be aware of the most recent technology. This book presents a survey of the recent advances of nonlinear optical applications. Emphasis will be on novel devices and materials, switching technology, optical computing, and important experimental results. Recent developments in topics which are of historical interest to researchers, and in the same time of potential use in the fields of all-optical communication and computing technologies, are also included. Additionally, a few new related topics which might provoke discussion are presented. The book includes chapters on nonlinear optics and applications; the nonlinear Schrodinger and associated equations that model spatio-temporal propagation; the supercontinuum light source; wideband ultrashort pulse fiber laser sources; lattice fabrication as well as their linear and nonlinear light guiding properties; the second-order EO effect (Pockels), the third-order (Kerr) and thermo-optical effects in optical waveguides and their applications in optical communication; and, the effect of magnetic field and its role in nonlinear optics, among other chapters.

  14. Optical Computing With Nonlinear Optics (United States)

    Khitrova, Galina; Gibbs, Hyatt; Peyghambarian, Nasser


    Nonlinear optics is becoming a new thrust in the field of optical computing and signal processing.14 Optical nonlinearity makes the device's transmission intensity dependent, so one can obtain the thresholding needed for logic decisionmaking. Thresholding is essential to digital optical computing, neural nets, and associative memories. GaAs etalons exhibit many of the characteristics desirable for the nonlinear devices including high speed (picosecond) and diode-laser compatability. However, demonstrations of the use of nonlinear decisionmaking for optical computing have used ZnS or ZnSe interference filters. They are slow (millisecond), but they can be used with the visible 514.5-nm output of an argon laser. We have used such filters to demonstrate all-optical logic operations, one-bit addition by symbolic substitution, and recognition of a three-spot pattern in an arbitrary 2 x 8 array of input beams. The application to associative memories is under study.

  15. Geometric nonlinear functional analysis volume 1

    CERN Document Server

    Benyamini, Yoav


    The book presents a systematic and unified study of geometric nonlinear functional analysis. This area has its classical roots in the beginning of the twentieth century and is now a very active research area, having close connections to geometric measure theory, probability, classical analysis, combinatorics, and Banach space theory. The main theme of the book is the study of uniformly continuous and Lipschitz functions between Banach spaces (e.g., differentiability, stability, approximation, existence of extensions, fixed points, etc.). This study leads naturally also to the classification of

  16. Nonlinear optical systems

    CERN Document Server

    Lugiato, Luigi; Brambilla, Massimo


    Guiding graduate students and researchers through the complex world of laser physics and nonlinear optics, this book provides an in-depth exploration of the dynamics of lasers and other relevant optical systems, under the umbrella of a unitary spatio-temporal vision. Adopting a balanced approach, the book covers traditional as well as special topics in laser physics, quantum electronics and nonlinear optics, treating them from the viewpoint of nonlinear dynamical systems. These include laser emission, frequency generation, solitons, optically bistable systems, pulsations and chaos and optical pattern formation. It also provides a coherent and up-to-date treatment of the hierarchy of nonlinear optical models and of the rich variety of phenomena they describe, helping readers to understand the limits of validity of each model and the connections among the phenomena. It is ideal for graduate students and researchers in nonlinear optics, quantum electronics, laser physics and photonics.

  17. Terahertz semiconductor nonlinear optics

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias


    In this proceedings we describe our recent results on semiconductor nonlinear optics, investigated using single-cycle THz pulses. We demonstrate the nonlinear absorption and self-phase modulation of strong-field THz pulses in doped semiconductors, using n-GaAs as a model system. The THz nonlinear...

  18. Nonlinear optics and photonics

    CERN Document Server

    He, Guang S


    This book provides a comprehensive presentation on most of the major topics in nonlinear optics and photonics, with equal emphasis on principles, experiments, techniques, and applications. It covers many major new topics including optical solitons, multi-photon effects, nonlinear photoelectric effects, fast and slow light , and Terahertz photonics. Chapters 1-10 present the fundamentals of modern nonlinear optics, and could be used as a textbook with problems provided at the end of each chapter. Chapters 11-17 cover the more advanced topics of techniques and applications of nonlinear optics and photonics, serving as a highly informative reference for researchers and experts working in related areas. There are also 16 pages of color photographs to illustrate the visual appearances of some typical nonlinear optical effects and phenomena. The book could be adopted as a textbook for both undergraduates and graduate students, and serve as a useful reference work for researchers and experts in the fields of physics...

  19. Geometric Phase Generated Optical Illusion. (United States)

    Yue, Fuyong; Zang, Xiaofei; Wen, Dandan; Li, Zile; Zhang, Chunmei; Liu, Huigang; Gerardot, Brian D; Wang, Wei; Zheng, Guoxing; Chen, Xianzhong


    An optical illusion, such as "Rubin's vase", is caused by the information gathered by the eye, which is processed in the brain to give a perception that does not tally with a physical measurement of the stimulus source. Metasurfaces are metamaterials of reduced dimensionality which have opened up new avenues for flat optics. The recent advancement in spin-controlled metasurface holograms has attracted considerate attention, providing a new method to realize optical illusions. We propose and experimentally demonstrate a metasurface device to generate an optical illusion. The metasurface device is designed to display two asymmetrically distributed off-axis images of "Rubin faces" with high fidelity, high efficiency and broadband operation that are interchangeable by controlling the helicity of the incident light. Upon the illumination of a linearly polarized light beam, the optical illusion of a 'vase' is perceived. Our result provides an intuitive demonstration of the figure-ground distinction that our brains make during the visual perception. The alliance between geometric metasurface and the optical illusion opens a pathway for new applications related to encryption, optical patterning, and information processing.

  20. Geometrical charged-particle optics

    CERN Document Server

    Rose, Harald H


    This reference monograph covers all theoretical aspects of modern geometrical charged-particle optics. It is intended as a guide for researchers, who are involved in the design of electron optical instruments and beam-guiding systems for charged particles, and as a tutorial for graduate students seeking a comprehensive treatment. Procedures for calculating the properties of systems with arbitrarily curved axes are outlined in detail and methods are discussed for designing and optimizing special components such as aberration correctors, spectrometers, energy filters, monochromators, ion traps, electron mirrors and cathode lenses. Also addressed is the design of novel electron optical components enabling sub-Angstroem spatial resolution and sub-0.1eV energy resolution. Relativistic motion and spin precession of the electron is treated in a concise way by employing a covariant five-dimensional procedure.

  1. Geometrical charged-particle optics

    CERN Document Server

    Rose, Harald


    This second edition is an extended version of the first edition of Geometrical Charged-Particle Optics. The updated reference monograph is intended as a guide for researchers and graduate students who are seeking a comprehensive treatment of the design of instruments and beam-guiding systems of charged particles and their propagation in electromagnetic fields. Wave aspects are included in this edition for explaining electron holography, the Aharanov-Bohm effect and the resolution of electron microscopes limited by diffraction. Several methods for calculating the electromagnetic field are presented and procedures are outlined for calculating the properties of systems with arbitrarily curved axis. Detailed methods are presented for designing and optimizing special components such as aberration correctors, spectrometers, energy filters monochromators, ion traps, electron mirrors and cathode lenses. In particular, the optics of rotationally symmetric lenses, quadrupoles, and systems composed of these elements are...

  2. Nonlinear Optical Terahertz Technology (United States)

    National Aeronautics and Space Administration — We develop a new approach to generation of THz radiation. Our method relies on mixing two optical frequency beams in a nonlinear crystalline Whispering Gallery Mode...

  3. 50 years of nonlinear optics

    International Nuclear Information System (INIS)

    Shen Yuanrang


    This article presents a brief introduction to the birth and early investigations of nonlinear optics, such as second harmonic generation,sum and difference frequency generation, stimulated Raman scattering,and self-action of light etc. Several important research achievements and applications of nonlinear optics are presented as well, including nonlinear optical spectroscopy, phase conjugation and adaptive optics, coherent nonlinear optics, and high-order harmonic generation. In the end, current and future research topics in nonlinear optics are summarized. (authors)

  4. Fundamentals of nonlinear optical materials

    Indian Academy of Sciences (India)

    Nonlinear optics; nonlinear polarization; optical fiber communication; optical switch- ing. PACS Nos 42.65Tg; ... The importance of nonlinear optics is to understand the nonlinear behavior in the induced polarization and to ..... but much work in material development and characterization remains to be done. 16. Conclusion.

  5. Nonlinear optics at interfaces

    International Nuclear Information System (INIS)

    Chen, C.K.


    Two aspects of surface nonlinear optics are explored in this thesis. The first part is a theoretical and experimental study of nonlinear intraction of surface plasmons and bulk photons at metal-dielectric interfaces. The second part is a demonstration and study of surface enhanced second harmonic generation at rough metal surfaces. A general formulation for nonlinear interaction of surface plasmons at metal-dielectric interfaces is presented and applied to both second and third order nonlinear processes. Experimental results for coherent second and third harmonic generation by surface plasmons and surface coherent antiStokes Raman spectroscopy (CARS) are shown to be in good agreement with the theory

  6. The Geometric Nonlinear Generalized Brazier Effect

    DEFF Research Database (Denmark)

    Nikolajsen, Jan Ánike; Lauridsen, Peter Riddersholm; Damkilde, Lars


    denoted the generalized Brazier effect. The original work of Brazier dealt with very large deformations that changed the cross section significantly and hereby also the bending moment of inertia and the bending moment capacity. In this paper the aim is to describe the Brazier effect for smaller...... deformation not taking into account the change in moment of inertia. However, the generalized Brazier effect gives additional stresses directed perpendicular to the beam axis. In composite structures these extra stresses may influence the fatigue life significantly. The paper demonstrates a linearized method...... that the generalized Brazier effect is a local effect not influencing the overall mechanical behavior of the structure significantly. The offset is a nonlinear geometric beam-type Finite Element calculation, which takes into account the large displacements and rotations. The beam-type model defines the stresses which...

  7. Fundamentals of nonlinear optics

    CERN Document Server

    Powers, Peter E


    Peter Powers's rigorous but simple description of a difficult field keeps the reader's attention throughout. … All chapters contain a list of references and large numbers of practice examples to be worked through. … By carefully working through the proposed problems, students will develop a sound understanding of the fundamental principles and applications. … the book serves perfectly for an introductory-level course for second- and third-order nonlinear optical phenomena. The author's writing style is refreshing and original. I expect that Fundamentals of Nonlinear Optics will fast become pop

  8. Nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind


    Since the 4e appeared, a fast evolution of the field has occurred. The 5e of this classic work provides an up-to-date account of the nonlinear phenomena occurring inside optical fibers, the basis of all our telecommunications infastructure as well as being used in the medical field. Reflecting the big developments in research, this new edition includes major new content: slow light effects, which offers a reduction in noise and power consumption and more ordered network traffic-stimulated Brillouin scattering; vectorial treatment of highly nonlinear fibers; and a brand new chapter o

  9. Essentials of nonlinear optics

    CERN Document Server

    Murti, Y V G S


    Current literature on Nonlinear Optics varies widely in terms of content, style, and coverage of specific topics, relative emphasis of areas and the depth of treatment. While most of these books are excellent resources for the researchers, there is a strong need for books appropriate for presenting the subject at the undergraduate or postgraduate levels in Universities. The need for such a book to serve as a textbook at the level of the bachelors and masters courses was felt by the authors while teaching courses on nonlinear optics to students of both science and engineering during the past two decades. This book has emerged from an attempt to address the requirement of presenting the subject at college level. A one-semester course covering the essentials can effectively be designed based on this.

  10. Terahertz Nonlinear Optics in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias C.


    We demonstrate the nonlinear optical effects – selfphase modulation and saturable absorption of a single-cycle THz pulse in a semiconductor. Resulting from THz-induced modulation of Drude plasma, these nonlinear optical effects, in particular, lead to self-shortening and nonlinear spectral...... breathing of a single-cycle THz pulse in a semiconductor....

  11. Online course Geometrical Optics for undergraduate students (United States)

    Bakholdin, Alexey; Voznesenskaya, Anna; Romanova, Galina; Ivanova, Tatiana; Tolstoba, Nadezhda; Ezhova, Kseniia; Garshin, Aleksei; Trifonov, Oleg; Sazonenko, Dmitry; Ekimenkova, Alisa


    The paper is devoted to the description of the on-line course "Geometrical Optics" placed on the national open-education platform. The course is purposed mainly for undergraduate students in optics and related fields. We discuss key features of the on-line form of this course, the issues of its realization and learning outcomes' evaluation.

  12. A practical guide to experimental geometrical optics

    CERN Document Server

    Garbovskiy, Yuriy A


    A concise, yet deep introduction to experimental, geometrical optics, this book begins with fundamental concepts and then develops the practical skills and research techniques routinely used in modern laboratories. Suitable for students, researchers and optical engineers, this accessible text teaches readers how to build their own optical laboratory and to design and perform optical experiments. It uses a hands-on approach which fills a gap between theory-based textbooks and laboratory manuals, allowing the reader to develop their practical skills in this interdisciplinary field, and also explores the ways in which this knowledge can be applied to the design and production of commercial optical devices. Including supplementary online resources to help readers track and evaluate their experimental results, this text is the ideal companion for anyone with a practical interest in experimental geometrical optics.

  13. Material and geometric nonlinear analysis of reinforced concrete frames

    Directory of Open Access Journals (Sweden)

    E. Parente Jr

    Full Text Available The analysis of reinforced concrete structures until failure requires the consideration of geometric and material nonlinearities. However, nonlinear analysis is much more complex and costly than linear analysis. In order to obtain a computationally efficient approach to nonlinear analysis of reinforced concrete structures, this work presents the formulation of a nonlinear plane frame element. Geometric nonlinearity is considered using the co-rotational approach and material nonlinearity is included using appropriate constitutive relations for concrete and steel. The integration of stress resultants and tangent constitutive matrix is carried out by the automatic subdivision of the cross-section and the application of the Gauss quadrature in each subdivision. The formulation and computational implementation are validated using experimental results available in the literature. Excellent results were obtained.


    NARCIS (Netherlands)

    Meijer, E.W.; Feringa, B.L.


    Chirality in molecular opto-electronics is limited sofar to the use of optically active liquid crystals and a number of optical phenomena are related to the helical macroscopic structure obtained by using one enantiomer, only. In this paper, the use of chirality in nonlinear optics and optical

  15. Applications of nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind


    * The only book describing applications of nonlinear fiber optics * Two new chapters on the latest developments: highly nonlinear fibers and quantum applications* Coverage of biomedical applications* Problems provided at the end of each chapterThe development of new highly nonlinear fibers - referred to as microstructured fibers, holey fibers and photonic crystal fibers - is the next generation technology for all-optical signal processing and biomedical applications. This new edition has been thoroughly updated to incorporate these key technology developments.The bo

  16. Field guide to nonlinear optics

    CERN Document Server

    Powers, Peter E


    Optomechanics is a field of mechanics that addresses the specific design challenges associated with optical systems. This [i]Field Guide [/i]describes how to mount optical components, as well as how to analyze a given design. It is intended for practicing optical and mechanical engineers whose work requires knowledge in both optics and mechanics. This Field Guide is designed for those looking for a condensed and concise source of key concepts, equations, and techniques for nonlinear optics. Topics covered include technologically important effects, recent developments in nonlinear optics

  17. Geometric Structure-Preserving Discretization Schemes for Nonlinear Elasticity (United States)


    application of the nonlinear elasticity complex is in developing mixed finite element methods for large deformations, which will be pursued in a future...framework of Hilbert complexes to write Hodge-type and Helmholtz-type orthogonal decompositions for second-order tensors. As some applications of these...conditions. 15.  SUBJECT TERMS geometric theory for nonlinear elasticity, discrete exterior calculus 16.  SECURITY CLASSIFICATION OF: 17.  LIMITATION

  18. Nonlinear optics principles and applications

    CERN Document Server

    Li, Chunfei


    This book reflects the latest advances in nonlinear optics. Besides the simple, strict mathematical deduction, it also discusses the experimental verification and possible future applications, such as the all-optical switches. It consistently uses the practical unit system throughout. It employs simple physical images, such as "light waves" and "photons" to systematically explain the main principles of nonlinear optical effects. It uses the first-order nonlinear wave equation in frequency domain under the condition of “slowly varying amplitude approximation" and the classical model of the interaction between the light and electric dipole. At the same time, it also uses the rate equations based on the energy-level transition of particle systems excited by photons and the energy and momentum conservation principles to explain the nonlinear optical phenomenon. The book is intended for researchers, engineers and graduate students in the field of the optics, optoelectronics, fiber communication, information tech...

  19. A mixed element for geometrically and physically nonlinear shell problems

    NARCIS (Netherlands)

    Bout, A.; Van Keulen, F.


    A triangular element for geometrical and physical nonlinear shell problems is described. The degrees of freedom are 18 displacement components and 6 rotation-like scalars. A key role in the description is played by a flat reference triangle through the vertices of the element. The governing

  20. Coated sphere scattering by geometric optics approximation. (United States)

    Mengran, Zhai; Qieni, Lü; Hongxia, Zhang; Yinxin, Zhang


    A new geometric optics model has been developed for the calculation of light scattering by a coated sphere, and the analytic expression for scattering is presented according to whether rays hit the core or not. The ray of various geometric optics approximation (GOA) terms is parameterized by the number of reflections in the coating/core interface, the coating/medium interface, and the number of chords in the core, with the degeneracy path and repeated path terms considered for the rays striking the core, which simplifies the calculation. For the ray missing the core, the various GOA terms are dealt with by a homogeneous sphere. The scattering intensity of coated particles are calculated and then compared with those of Debye series and Aden-Kerker theory. The consistency of the results proves the validity of the method proposed in this work.

  1. Extreme Nonlinear Optics An Introduction

    CERN Document Server

    Wegener, Martin


    Following the birth of the laser in 1960, the field of "nonlinear optics" rapidly emerged. Today, laser intensities and pulse durations are readily available, for which the concepts and approximations of traditional nonlinear optics no longer apply. In this regime of "extreme nonlinear optics," a large variety of novel and unusual effects arise, for example frequency doubling in inversion symmetric materials or high-harmonic generation in gases, which can lead to attosecond electromagnetic pulses or pulse trains. Other examples of "extreme nonlinear optics" cover diverse areas such as solid-state physics, atomic physics, relativistic free electrons in a vacuum and even the vacuum itself. This book starts with an introduction to the field based primarily on extensions of two famous textbook examples, namely the Lorentz oscillator model and the Drude model. Here the level of sophistication should be accessible to any undergraduate physics student. Many graphical illustrations and examples are given. The followi...

  2. Oscillating solitons in nonlinear optics

    Indian Academy of Sciences (India)

    Abstract. Oscillating solitons are obtained in nonlinear optics. Analytical study of the variable- coefficient nonlinear Schrödinger equation, which is used to describe the soliton propagation in those systems, is carried out using the Hirota's bilinear method. The bilinear forms and analytic soliton solutions are derived, and the ...

  3. Inflationary perturbation theory is geometrical optics in phase space (United States)

    Seery, David; Mulryne, David J.; Frazer, Jonathan; Ribeiro, Raquel H.


    A pressing problem in comparing inflationary models with observation is the accurate calculation of correlation functions. One approach is to evolve them using ordinary differential equations ("transport equations"), analogous to the Schwinger-Dyson hierarchy of in-out quantum field theory. We extend this approach to the complete set of momentum space correlation functions. A formal solution can be obtained using raytracing techniques adapted from geometrical optics. We reformulate inflationary perturbation theory in this language, and show that raytracing reproduces the familiar "δN" Taylor expansion. Our method produces ordinary differential equations which allow the Taylor coefficients to be computed efficiently. We use raytracing methods to express the gauge transformation between field fluctuations and the curvature perturbation, ζ, in geometrical terms. Using these results we give a compact expression for the nonlinear gauge-transform part of fNL in terms of the principal curvatures of uniform energy-density hypersurfaces in field space.

  4. Geometric properties of Banach spaces and nonlinear iterations

    CERN Document Server

    Chidume, Charles


    Nonlinear functional analysis and applications is an area of study that has provided fascination for many mathematicians across the world. This monograph delves specifically into the topic of the geometric properties of Banach spaces and nonlinear iterations, a subject of extensive research over the past thirty years. Chapters 1 to 5 develop materials on convexity and smoothness of Banach spaces, associated moduli and connections with duality maps. Key results obtained are summarized at the end of each chapter for easy reference. Chapters 6 to 23 deal with an in-depth, comprehensive and up-to-date coverage of the main ideas, concepts and results on iterative algorithms for the approximation of fixed points of nonlinear nonexpansive and pseudo-contractive-type mappings. This includes detailed workings on solutions of variational inequality problems, solutions of Hammerstein integral equations, and common fixed points (and common zeros) of families of nonlinear mappings. Carefully referenced and full of recent,...

  5. Nonlinear optical properties and nonlinear optical probes of organic materials (United States)

    Meredith, Gerald R.


    Nonlinear optical processes and electro-optical effects are expected to have increasing importance as the information age matures and photonics augment electronics in various high density and high bandwidth technologies. Whereas for electronics the emphasis is in construction of smaller device structures from a few parent materials, for organic materials the direction of materials research has been reversed. For some time it's been known that some molecular structures engender exceptionally large molecular nonlinear-polarization responses. If such molecules could be assembled in convenient, versatile, and reliable ways, the resulting materials would be very useful or even enabling in various photonics applications. The mature science and art of chemistry allows very good control over molecular composition and structure and, as will be illustrated in this talk, our knowledge of hyperpolarizability structure- property relationships is advancing rapidly. However, the science of fabrication and arrangement in molecular ensembles and polymers is rather primitive. Thus the goal to develop the appropriately structured materials for utilization in nonlinear and electro-optics has fostered the widespread use of nonlinear optical processes to probe the nature of supramolecular order and assembly. Examples of intrinsic and artificially assembled structures of crystals, molecular aggregates, polymeric orientational electrets and molecular mono- and multi-layer thin films will be shown. Nonlinear optical processes, primarily second-harmonic generation, provide unique probes of these structures, their assembly, and evolution.

  6. Nonclassical properties of a nonlinear generalized geometric state

    Energy Technology Data Exchange (ETDEWEB)

    Abdalla, M Sebawe [Mathematics Department, College of Science, King Saud University, PO Box 2455, Riyadh 11451 (Saudi Arabia); Obada, A-S F [Department of Mathematics, Faculty of Science, Al-Azhar University, Nasr City 11884, Cairo (Egypt); Darwish, M [Department of Physics, Faculty of Education, Suez Canal University, Al-Arish (Egypt)], E-mail:


    In this paper, we introduce and investigate some properties of a nonlinear generalized geometric state (the state that interpolates between the number state and a nonlinear pure thermal state). We mainly concentrate on the statistical properties. We have discussed the normal squeezing as well as the amplitude squared squeezing, further the Mandel's q-parameter is also considered. The investigation is also extended to include the quasi-probability distribution functions (W-Wigner and Q-functions). The quadrature distribution and the phase properties in the Pegg-Barnett formalism besides the phase variances are considered.

  7. Nonlinear Optics of Hexaphenyl Nanofibers

    DEFF Research Database (Denmark)

    Balzer, Frank; Al-Shamery, Katharina; Neuendorf, Rolf


    The nonlinear optical response of films of needle-shaped para-hexaphenyl nanoaggregates on mica surfaces is investigated. Two-photon luminescence as well as optical second harmonic generation (SHG) are observed following excitation with femtosecond pulses at 770 nm. Polarization dependent...... measurements reveal that the nonlinear optical transition dipole moment is oriented with an angle of 75° with respect to the needles long axes. The absolute value of the macroscopic second-order susceptibility, averaged over a size distribution of p-6P nanoaggregates, is estimated to be of the order of 6...

  8. Geometric-optical illusions at isoluminance. (United States)

    Hamburger, Kai; Hansen, Thorsten; Gegenfurtner, Karl R


    The idea of a largely segregated processing of color and form was initially supported by observations that geometric-optical illusions vanish under isoluminance. However, this finding is inconsistent with some psychophysical studies and also with physiological evidence showing that color and luminance are processed together by largely overlapping sets of neurons in the LGN, in V1, and in extrastriate areas. Here we examined the strength of nine geometric-optical illusions under isoluminance (Delboeuf, Ebbinghaus, Hering, Judd, Müller-Lyer, Poggendorff, Ponzo, Vertical, Zöllner). Subjects interactively manipulated computer-generated line drawings to counteract the illusory effect. In all cases, illusions presented under isoluminance (both for colors drawn from the cardinal L-M or S-(L+M) directions of DKL color space) were as effective as the luminance versions (both for high and low contrast). The magnitudes of the illusion effects were highly correlated across subjects for the different conditions. In two additional experiments we determined that the strong illusions observed under isoluminance were not due to individual deviations from the photometric point of isoluminance or due to chromatic aberrations. Our findings show that our conscious percept is affected similarly for both isoluminance and luminance conditions, suggesting that the joint processing for chromatic and luminance defined contours may extend well beyond early visual areas.

  9. Nonlinear Optics: Principles and Applications

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Tidemand-Lichtenberg, Peter

    As nonlinear optics further develops as a field of research in electromagnetic wave propagation, its state-of-the-art technologies will continue to strongly impact real-world applications in a variety of fields useful to the practicing scientist and engineer. From basic principles to examples...... of applications, Nonlinear Optics: Principles and Applications effectively bridges physics and mathematics with relevant applied material for real-world use. The book progresses naturally from fundamental aspects to illustrative examples, and presents a strong theoretical foundation that equips the reader...

  10. Nanoplasmonic solution for nonlinear optics

    DEFF Research Database (Denmark)

    Bache, Morten; Lavrinenko, Andrei; Lysenko, Oleg


    . The quality of samples was inspected using the optical microscope, scanningelectron microscope, atomic force microscope, and ellipsometer. The ready wafer was diced into several rectangular sliced with the fixed width of 15 mm and the different length from 2 mm to 6 mm for optical characterization......Nonlinear optical properties of dielectric waveguides are well known and are widely used in moderntelecommunication systems [1]. However, the fundamental law of diffraction imposes physical limitation for integration of dielectric photonics and semiconductor electronics [2]. A possible way...... to combine the high speed of a photonic device with the compact size of an electronic device is to produce ananoplasmonic device based on metal waveguides. The successful solutions can be used for future sustainable technologies. In meantime, nonlinear optics of metal waveguides is not fully understood...

  11. Geometric nonlinear formulation for thermal-rigid-flexible coupling system (United States)

    Fan, Wei; Liu, Jin-Yang


    This paper develops geometric nonlinear hybrid formulation for flexible multibody system with large deformation considering thermal effect. Different from the conventional formulation, the heat flux is the function of the rotational angle and the elastic deformation, therefore, the coupling among the temperature, the large overall motion and the elastic deformation should be taken into account. Firstly, based on nonlinear strain-displacement relationship, variational dynamic equations and heat conduction equations for a flexible beam are derived by using virtual work approach, and then, Lagrange dynamics equations and heat conduction equations of the first kind of the flexible multibody system are obtained by leading into the vectors of Lagrange multiplier associated with kinematic and temperature constraint equations. This formulation is used to simulate the thermal included hub-beam system. Comparison of the response between the coupled system and the uncoupled system has revealed the thermal chattering phenomenon. Then, the key parameters for stability, including the moment of inertia of the central body, the incident angle, the damping ratio and the response time ratio, are analyzed. This formulation is also used to simulate a three-link system applied with heat flux. Comparison of the results obtained by the proposed formulation with those obtained by the approximate nonlinear model and the linear model shows the significance of considering all the nonlinear terms in the strain in case of large deformation. At last, applicability of the approximate nonlinear model and the linear model are clarified in detail.

  12. Unconstrained Finite Element for Geometrical Nonlinear Dynamics of Shells

    Directory of Open Access Journals (Sweden)

    Humberto Breves Coda


    Full Text Available This paper presents a positional FEM formulation to deal with geometrical nonlinear dynamics of shells. The main objective is to develop a new FEM methodology based on the minimum potential energy theorem written regarding nodal positions and generalized unconstrained vectors not displacements and rotations. These characteristics are the novelty of the present work and avoid the use of large rotation approximations. A nondimensional auxiliary coordinate system is created, and the change of configuration function is written following two independent mappings from which the strain energy function is derived. This methodology is called positional and, as far as the authors' knowledge goes, is a new procedure to approximated geometrical nonlinear structures. In this paper a proof for the linear and angular momentum conservation property of the Newmark algorithm is provided for total Lagrangian description. The proposed shell element is locking free for elastic stress-strain relations due to the presence of linear strain variation along the shell thickness. The curved, high-order element together with an implicit procedure to solve nonlinear equations guarantees precision in calculations. The momentum conserving, the locking free behavior, and the frame invariance of the adopted mapping are numerically confirmed by examples.

  13. Nonlinear optics principles and applications

    CERN Document Server

    Rottwitt, Karsten


    IntroductionReview of linear opticsInduced polarizationHarmonic oscillator modelLocal field correctionsEstimated nonlinear responseSummaryTime-domain material responseThe polarization time-response functionThe Born-Oppenheimer approximationRaman scattering response function of silicaSummaryMaterial response in the frequency domain, susceptibility tensorsThe susceptibility tensorThe induced polarization in the frequency domainSum of monochromatic fieldsThe prefactor to the induced polarizationThird-order polarization in the Born-Oppenheimer approximation in the frequency domainKramers-Kronig relationsSummarySymmetries in nonlinear opticsSpatial symmetriesSecond-order materialsThird-order nonlinear materialsCyclic coordinate-systemContracted notation for second-order susceptibility tensorsSummaryThe nonlinear wave equationMono and quasi-monochromatic beamsPlane waves - the transverse problemWaveguidesVectorial approachNonlinear birefringenceSummarySecond-order nonlinear effectsGeneral theoryCoupled wave theoryP...

  14. Impact of carbon nanotube geometrical volume on nonlinear absorption and scattering properties (United States)

    Nair, Vijayakumar Sadasivan; Pusala, Aditya; Hatamimoslehabadi, Maryam; Yelleswarapu, Chandra S.


    Nonlinear optical (NLO) properties of carbon nanostructures are of great interest due to their broadband spectral response. As carbon nanotubes (CNTs) can be synthesized with various lengths, thicknesses, and numbers of layers, their optical properties can also be different. We have performed side-by-side comparative studies of the relationship between the geometrical volume and NLO properties of CNTs. The real and imaginary components of the third order optical nonlinearity are obtained using well-known Z-scan technique. While the transmission and scattered light are detected using photodiodes, the generated photoacoustic signal is recorded simultaneously using an ultrasonic transducer. Results show an inverse relationship between the volume of CNTs and their NLO properties. This can be attributed to the availability of more nanoparticles within the laser beam profile and concurrent generation of scattering sites upon the absorption of incident radiation.

  15. Oscillating solitons in nonlinear optics

    Indian Academy of Sciences (India)

    ... are derived, and the relevant properties and features of oscillating solitons are illustrated. Oscillating solitons are controlled by the reciprocal of the group velocity and Kerr nonlinearity. Results of this paper will be valuable to the study of dispersion-managed optical communication system and mode-locked fibre lasers.

  16. Nonlinear compression of optical solitons

    Indian Academy of Sciences (India)

    pulse area can be conserved by the inclusion of gain (or loss) and phase modulation effects. Keywords. Optical solitons; bright and dark solitons; nonlinear compression; phase modulation; fibre amplification; loss. PACS Nos 42.81. Dp; 02.30 Jr; 04.30 Nk. 1. Introduction. The term soliton refers to special kinds of waves that ...

  17. Basic considerations on surface optical nonlinearities

    International Nuclear Information System (INIS)

    Guyot-Sionnest, P.; Chen, W.; Shen, Y.R.


    The origins of the surface nonlinearity in surface second harmonic generation are discussed. It is shown that this second-order nonlinear optical process is characterized by a surface nonlinear susceptibility tensor containing both local and nonlocal contributions

  18. Nonlinear fibre optics overview

    DEFF Research Database (Denmark)

    Travers, J. C.; Frosz, Michael Henoch; Dudley, J. M.


    The optical fiber based supercontinuum source has recently become a significant scientific and commercial success, with applications ranging from frequency comb production to advanced medical imaging. This one-of-a-kind book explains the theory of fiber supercontinuum broadening, describes...... the diverse operational regimes and indicates principal areas of applications, making it a very important guide for researchers and graduate students. With contributions from major figures and groups who have pioneered research in this field, the book describes the historical development of the subject...

  19. Nonlinear fiber optics formerly quantum electronics

    CERN Document Server

    Agrawal, Govind


    The field of nonlinear fiber optics has grown substantially since the First Edition of Nonlinear Fiber Optics, published in 1989. Like the First Edition, this Second Edition is a comprehensive, tutorial, and up-to-date account of nonlinear optical phenomena in fiber optics. It synthesizes widely scattered research material and presents it in an accessible manner for students and researchers already engaged in or wishing to enter the field of nonlinear fiber optics. Particular attention is paid to the importance of nonlinear effects in the design of optical fiber communication systems. This is

  20. Geometrically Nonlinear Transient Response of Laminated Plates with Nonlinear Elastic Restraints

    Directory of Open Access Journals (Sweden)

    Shaochong Yang


    Full Text Available To investigate the dynamic behavior of laminated plates with nonlinear elastic restraints, a varied constraint force model and a systematic numerical procedure are presented in this work. Several kinds of typical relationships of force-displacement for spring are established to simulate the nonlinear elastic restraints. In addition, considering the restraining moments of flexible pads, the pads are modeled by translational and rotational springs. The displacement- dependent constraint forces are added to the right-hand side of equations of motion and treated as additional applied loads. These loads can be explicitly defined, via an independent set of nonlinear load functions. The time histories of transverse displacements at typical points of the laminated plate are obtained through the transient analysis. Numerical examples show that the present method can effectively treat the geometrically nonlinear transient response of plates with nonlinear elastic restraints.

  1. Active Learning Environment with Lenses in Geometric Optics (United States)

    Tural, Güner


    Geometric optics is one of the difficult topics for students within physics discipline. Students learn better via student-centered active learning environments than the teacher-centered learning environments. So this study aimed to present a guide for middle school teachers to teach lenses in geometric optics via active learning environment…

  2. Determination of optical constants and nonlinear optical coefficients ...

    Indian Academy of Sciences (India)

    −7 cm2/W and nonlinear absorption coefficient, β = 6.31×10. −3 cm/W. Optical limiting characteris- tics of the dye-doped polymer film was studied. The result reveals that Violet 1 can be a promising material for optical limiting applications. Keywords. Absorption spectra; nonlinear optics; optical constants; optical limiting.

  3. Geometrical Effects on Nonlinear Electrodiffusion in Cell Physiology (United States)

    Cartailler, J.; Schuss, Z.; Holcman, D.


    We report here new electrical laws, derived from nonlinear electrodiffusion theory, about the effect of the local geometrical structure, such as curvature, on the electrical properties of a cell. We adopt the Poisson-Nernst-Planck equations for charge concentration and electric potential as a model of electrodiffusion. In the case at hand, the entire boundary is impermeable to ions and the electric field satisfies the compatibility condition of Poisson's equation. We construct an asymptotic approximation for certain singular limits to the steady-state solution in a ball with an attached cusp-shaped funnel on its surface. As the number of charge increases, they concentrate at the end of cusp-shaped funnel. These results can be used in the design of nanopipettes and help to understand the local voltage changes inside dendrites and axons with heterogeneous local geometry.

  4. Nonlinear optical interactions in silicon waveguides

    Directory of Open Access Journals (Sweden)

    Kuyken B.


    Full Text Available The strong nonlinear response of silicon photonic nanowire waveguides allows for the integration of nonlinear optical functions on a chip. However, the detrimental nonlinear optical absorption in silicon at telecom wavelengths limits the efficiency of many such experiments. In this review, several approaches are proposed and demonstrated to overcome this fundamental issue. By using the proposed methods, we demonstrate amongst others supercontinuum generation, frequency comb generation, a parametric optical amplifier, and a parametric optical oscillator.

  5. Nonlinear optical crystals a complete survey

    CERN Document Server

    Nikogosyan, David N


    Nonlinear optical crystals are widely used in modern optical science and technology for frequency conversion of laser light, i.e. to generate laser radiation at any specific wavelength in visible, UV or IR spectral regions. This unrivalled reference book contains the most complete and up-to-date information on properties of nonlinear optical crystals. It includes: * Database of 63 common and novel nonlinear optical crystals * Periodically-poled and self-frequency-doubling materials * Full description of linear and nonlinear optical properties * Significant amount of crystallophysical, thermophysical, spectroscopic, electro-optic and magneto-optic information * 7 mini-reviews on novel applications, such as deep-UV light generation, terahertz-wave generation, ultrashort laser pulse compression, photonic band-gap crystals, x3 nonlinearity, etc. * More than 1500 different references with full titles It is a vital source of information for scientists and engineers dealing with modern applications of nonlinear opti...

  6. Extreme nonlinear energy exchanges in a geometrically nonlinear lattice oscillating in the plane (United States)

    Zhang, Zhen; Manevitch, Leonid I.; Smirnov, Valeri; Bergman, Lawrence A.; Vakakis, Alexander F.


    We study the in-plane damped oscillations of a finite lattice of particles coupled by linear springs under distributed harmonic excitation. Strong nonlinearity in this system is generated by geometric effects due to the in-plane stretching of the coupling spring elements. The lattice has a finite number of nonlinear transverse standing waves (termed nonlinear normal modes - NNMs), and an equal number of axial linear modes which are nonlinearly coupled to the transverse ones. Nonlinear interactions between the transverse and axial modes under harmonic excitation give rise to unexpected and extreme nonlinear energy exchanges in the lattice. In particular, we directly excite a transverse NNM by harmonic forcing (causing simulataneous indirect excitation of a corresponding axial linear mode due to nonlinear coupling), and identify three energy transfer mechanisms in the lattice. First, we detect the stable response of the directly excited transverse NNM (despite its instability in the absence of forcing), with simultaneous stability of the indirectly excited axial linear mode. Second, by changing the system and forcing parameters we report extreme nonlinear "energy explosions," whereby, after an initial regime of stability, the directly excited transverse NNM loses stability, leading to abrupt excitation of all transverse and axial modes of the lattice, at all possible wave numbers. This strong instability is triggered by the parametric instability of an indirectly excited axial mode which builds energy until the explosion. This is proved through theoretical analysis. Finally, in other parameter ranges we report intermittent, intense energy transfers from the directly excited transverse NNM to a small set of transverse NNMs with smaller wavelengths, and from the indirectly excited axial mode to a small set of axial modes, but with larger wavelengths. These intermittent energy transfers resemble energy cascades occurring in turbulent flows. Our results show that

  7. Strongly nonlinear free vibration of four edges simply supported stiffened plates with geometric imperfections

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhaoting; Wang, Rong Hui; Chen, Li; Dong, Chung Uang [School of Civil Engineering and Transportation, South China University of Technology, Guangzhou (China)


    This article investigated the strongly nonlinear free vibration of four edges simply supported stiffened plates with geometric imperfections. The von Karman nonlinear strain-displacement relationships are applied. The nonlinear vibration of stiffened plate is reduced to a one-degree-of-freedom nonlinear system by assuming mode shapes. The Multiple scales Lindstedt-Poincare method (MSLP) and Modified Lindstedt-Poincare method (MLP) are used to solve the governing equations of vibration. Numerical examples for stiffened plates with different initial geometric imperfections are presented in order to discuss the influences to the strongly nonlinear free vibration of the stiffened plate. The results showed that: the frequency ratio reduced as the initial geometric imperfections of plate increased, which showed that the increase of the initial geometric imperfections of plate can lead to the decrease of nonlinear effect; by comparing the results calculated by MSLP method, using MS method to study strongly nonlinear vibration can lead to serious mistakes.

  8. Nonlinear Photonics and Novel Optical Phenomena

    CERN Document Server

    Morandotti, Roberto


    Nonlinear Photonics and Novel Optical Phenomena contains contributed chapters from leading experts in nonlinear optics and photonics, and provides a comprehensive survey of fundamental concepts as well as hot topics in current research on nonlinear optical waves and related novel phenomena. The book covers self-accelerating airy beams, integrated photonics based on high index doped-silica glass, linear and nonlinear spatial beam dynamics in photonic lattices and waveguide arrays, polariton solitons and localized structures in semiconductor microcavities, terahertz waves, and other novel phenomena in different nanophotonic and optical systems.

  9. Optical computation based on nonlinear total reflectional optical ...

    Indian Academy of Sciences (India)

    ∗ ... kind of all-optical computation which is based on the polarization coding technique and the nonlinear total reflectional ..... [8] G P Agrawal, Nonlinear fiber optics, 3rd edn (Academic Press, Boston, 2005). S X Qian and R Y Zhu, Nonlinear ...

  10. Electrifying photonic metamaterials for tunable nonlinear optics. (United States)

    Kang, Lei; Cui, Yonghao; Lan, Shoufeng; Rodrigues, Sean P; Brongersma, Mark L; Cai, Wenshan


    Metamaterials have not only enabled unprecedented flexibility in producing unconventional optical properties that are not found in nature, they have also provided exciting potential to create customized nonlinear media with high-order properties correlated to linear behaviour. Two particularly compelling directions are active metamaterials, whose optical properties can be purposely tailored by external stimuli in a reversible manner, and nonlinear metamaterials, which enable intensity-dependent frequency conversion of light waves. Here, by exploring the interaction of these two directions, we leverage the electrical and optical functions simultaneously supported in nanostructured metals and demonstrate electrically controlled nonlinear optical processes from a metamaterial. Both second harmonic generation and optical rectification, enhanced by the resonance behaviour in the metamaterial absorber, are modulated externally with applied voltage signals. Our results reveal an opportunity to exploit optical metamaterials as self-contained, dynamic electro-optic systems with intrinsically embedded electrical functions and optical nonlinearities.

  11. A Global Geometric Framework for Nonlinear Dimensionality Reduction (United States)

    Tenenbaum, Joshua B.; de Silva, Vin; Langford, John C.


    Scientists working with large volumes of high-dimensional data, such as global climate patterns, stellar spectra, or human gene distributions, regularly confront the problem of dimensionality reduction: finding meaningful low-dimensional structures hidden in their high-dimensional observations. The human brain confronts the same problem in everyday perception, extracting from its high-dimensional sensory inputs-30,000 auditory nerve fibers or 106 optic nerve fibers-a manageably small number of perceptually relevant features. Here we describe an approach to solving dimensionality reduction problems that uses easily measured local metric information to learn the underlying global geometry of a data set. Unlike classical techniques such as principal component analysis (PCA) and multidimensional scaling (MDS), our approach is capable of discovering the nonlinear degrees of freedom that underlie complex natural observations, such as human handwriting or images of a face under different viewing conditions. In contrast to previous algorithms for nonlinear dimensionality reduction, ours efficiently computes a globally optimal solution, and, for an important class of data manifolds, is guaranteed to converge asymptotically to the true structure.

  12. Nonlinear Thermo-mechanical Finite Element Analysis of Polymer Foam Cored Sandwich Structures including Geometrical and Material Nonlinearity

    DEFF Research Database (Denmark)

    Palleti, Hara Naga Krishna Teja; Thomsen, Ole Thybo; Taher, Siavash Talebi

    In this paper, polymer foam cored sandwich structures with fibre reinforced composite face sheets subjected to combined mechanical and thermal loads will be analysed using the commercial FE code ABAQUS® incorporating both material and geometrical nonlinearity. Large displacements and rotations...

  13. Ultrathin Nonlinear Metasurface for Optical Image Encoding. (United States)

    Walter, Felicitas; Li, Guixin; Meier, Cedrik; Zhang, Shuang; Zentgraf, Thomas


    Security of optical information is of great importance in modern society. Many cryptography techniques based on classical and quantum optics have been widely explored in the linear optical regime. Nonlinear optical encryption in which encoding and decoding involve nonlinear frequency conversions represents a new strategy for securing optical information. Here, we demonstrate that an ultrathin nonlinear photonic metasurface, consisting of meta-atoms with 3-fold rotational symmetry, can be used to hide optical images under illumination with a fundamental wave. However, the hidden image can be read out from second harmonic generation (SHG) waves. This is achieved by controlling the destructive and constructive interferences of SHG waves from two neighboring meta-atoms. In addition, we apply this concept to obtain gray scale SHG imaging. Nonlinear metasurfaces based on space variant optical interference open new avenues for multilevel image encryption, anticounterfeiting, and background free image reconstruction.

  14. Nonlinear optics quantum computing with circuit QED. (United States)

    Adhikari, Prabin; Hafezi, Mohammad; Taylor, J M


    One approach to quantum information processing is to use photons as quantum bits and rely on linear optical elements for most operations. However, some optical nonlinearity is necessary to enable universal quantum computing. Here, we suggest a circuit-QED approach to nonlinear optics quantum computing in the microwave regime, including a deterministic two-photon phase gate. Our specific example uses a hybrid quantum system comprising a LC resonator coupled to a superconducting flux qubit to implement a nonlinear coupling. Compared to the self-Kerr nonlinearity, we find that our approach has improved tolerance to noise in the qubit while maintaining fast operation.

  15. Growth and characterization of nonlinear optical single crystals: bis ...

    Indian Academy of Sciences (India)


    Organic compound; growth from solution; characterization; nonlinear optical materials. 1. Introduction. Organic nonlinear optical (NLO) materials have attracted much attention due to their potential applications in telecommunication, optical switching, optical frequency conversion, THz generation, electro-optical and inte-.

  16. Improvement of nonlinear diffusion equation using relaxed geometric mean filter for low PSNR images

    DEFF Research Database (Denmark)

    Nadernejad, Ehsan


    A new method to improve the performance of low PSNR image denoising is presented. The proposed scheme estimates edge gradient from an image that is regularised with a relaxed geometric mean filter. The proposed method consists of two stages; the first stage consists of a second order nonlinear...... anisotropic diffusion equation with new neighboring structure and the second is a relaxed geometric mean filter, which processes the output of nonlinear anisotropic diffusion equation. The proposed algorithm enjoys the benefit of both nonlinear PDE and relaxed geometric mean filter. In addition, the algorithm...... and quantitatively, is produced....

  17. Introduction: Nonlinear Optics (NLO) 2017 feature issue. (United States)

    Hagan, David J; Denz, Cornelia; Suchowski, Haim; Biaggio, Ivan; Sheik-Bahae, Mansoor


    The editors introduce the feature issue on "Nonlinear Optics 2017," based on the topics presented at the NLO 2017 conference, which was held in Waikoloa, Hawaii, USA from July 17-21, 2017. This feature issue is jointly published by Optics Express and Optical Materials Express.

  18. Controlling lightwave in Riemann space by merging geometrical optics with transformation optics. (United States)

    Liu, Yichao; Sun, Fei; He, Sailing


    In geometrical optical design, we only need to choose a suitable combination of lenses, prims, and mirrors to design an optical path. It is a simple and classic method for engineers. However, people cannot design fantastical optical devices such as invisibility cloaks, optical wormholes, etc. by geometrical optics. Transformation optics has paved the way for these complicated designs. However, controlling the propagation of light by transformation optics is not a direct design process like geometrical optics. In this study, a novel mixed method for optical design is proposed which has both the simplicity of classic geometrical optics and the flexibility of transformation optics. This mixed method overcomes the limitations of classic optical design; at the same time, it gives intuitive guidance for optical design by transformation optics. Three novel optical devices with fantastic functions have been designed using this mixed method, including asymmetrical transmissions, bidirectional focusing, and bidirectional cloaking. These optical devices cannot be implemented by classic optics alone and are also too complicated to be designed by pure transformation optics. Numerical simulations based on both the ray tracing method and full-wave simulation method are carried out to verify the performance of these three optical devices.

  19. Nonlinear soliton matching between optical fibers

    DEFF Research Database (Denmark)

    Agger, Christian; Sørensen, Simon Toft; Thomsen, Carsten L.


    In this Letter, we propose a generic nonlinear coupling coefficient, η2 NL ¼ ηjγ=β2jfiber2=jγ=β2jfiber1, which gives a quantitative measure for the efficiency of nonlinear matching of optical fibers by describing how a fundamental soliton couples from one fiber into another. Specifically, we use η......NL to demonstrate a significant soliton selffrequency shift of a fundamental soliton, and we show that nonlinear matching can take precedence over linear mode matching. The nonlinear coupling coefficient depends on both the dispersion (β2) and nonlinearity (γ), as well as on the power coupling efficiency η. Being...

  20. A geometric morphometric assessment of the optic cup in glaucoma. (United States)

    Sanfilippo, Paul G; Cardini, Andrea; Sigal, Ian A; Ruddle, Jonathan B; Chua, Brian E; Hewitt, Alex W; Mackey, David A


    The morphologic appearance of the optic disc is of interest in glaucoma. In contrast to descriptive classification systems that are currently used, a quantitative approach to the analysis of optic disc morphology is required. Our goal was to determine the optimal method for quantifying optic cup shape by comparing traditional (ovality, form-factor and neuroretinal rim (NRR) width ratio) and geometric morphometric approaches. Left optic disc stereophotographs of 160 (80 normal and 80 glaucomatous (stratified by severity)) subjects were examined. The optic cup margins were stereoscopically delineated with a custom tracing system and saved as a series of discrete points. The geometric morphometric methods of elliptic Fourier analysis (EFA) and sliding semi-landmark analysis (SSLA) were used to eliminate variation unrelated to shape (e.g. size) and yield a series of shape variables. Differences in optic cup shape between normal and glaucoma groups were investigated. Discriminant functions were computed and the sensitivity and specificity of each technique determined. Receiver operator characteristic (ROC) curves were calculated for all methods and evaluated in their potential to discriminate between normal and glaucomatous eyes based on the shape variables. All geometric morphometric methods revealed differences between normal and glaucomatous eyes in optic cup shape, in addition to the traditional parameters of ovality, form-factor and NRR width ratio (pcurve (AUC) (0.91). EFA (72 points) performed similarly well (74%, 0.89) as did the set of traditional shape-based variables (76%, 0.86). This study demonstrated that a geometric morphometric approach for discriminating between normal and glaucomatous eyes in optic cup shape is superior to that provided by traditional single parameter shape measures. Such analytical techniques could be incorporated into future automated optic disc screening modalities. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  1. A geometric criterion for the stability of forced oscillations in non-linear mechanics (1961)

    International Nuclear Information System (INIS)

    Blaquiere, A.


    The author completes the two-parameter diagram theory which he has previously explained, by giving a geometric criterion of stability for a non-linear system under forced conditions. After two simple geometric transformations of the diagram he obtains the separators which are the boundary conditions for the zones of stability. (author) [fr

  2. Experimental Characterization of Nonlinear Optical Materials (United States)

    Knox, Katie; Yang, Chuan; Liu, Zhiwen


    An optical system based on a half-wave plate-polarizer attenuator was designed to determine the transmitted light through materials that behave nonlinearly in the presence of high-energy picosecond laser pulses. The sample's nonlinear absorbance of a frequency-doubled Nd:YAG laser was measured as the energy of the incident light was regulated by the rotation of a half-wave plate. The optical system was used to measure the absorption of two linear samples as well as a nonlinear liquid crystal. Experimental results revealed that the optical material, which was composed of gold nanospheres in the nonlinear liquid L34, behaved as expected in the presence of lower input energies, but the attenuated beam did not reach a high enough energy to observe the full limiting effects of the nonlinear material.

  3. Nuclear matter as a nonlinear optical medium

    International Nuclear Information System (INIS)

    Hefter, E.F.; Papini, G.


    This paper is concerned with the question whether nuclear matter should be considered as a nonlinear optical medium. Taking, in a pragmatic way, quality and quantity of the results of well-established linear and nonlinear approaches as the main criterion, an affirmative answer is seen to be consistent with long-standing practices adhered to in nuclear physics

  4. Completely integrable models of nonlinear optics

    Indian Academy of Sciences (India)

    Abstract. The models of the nonlinear optics in which solitons appeared are considered. These models are of paramount importance in studies of nonlinear wave phenomena. The classical ex- amples of phenomena of this kind are the self-focusing, self-induced transparency and parametric interaction of three waves.

  5. Nonlinear Optical Effects in Liquid Crystals. (United States)


    nonlinear optical devices using these media 3 ,4 ,5 and more recently to use nonlinear optical measurements to study the properties of materials . However...susceptibilities Lasers, Nematic, Cholesteric, Flexoelectric , Second-harmonic generation 20M AV*--YRAc rR-r, m, revere i It nf le4U7 siad Idsiully byr... flexoelectric effect can give rise to second-harmonic generation in nematic liquid crystal and the birefringence of nematic crystal can be used to achieve

  6. Complementary Huygens principle for geometrical and nongeometrical optics

    International Nuclear Information System (INIS)

    Luis, Alfredo


    We develop a fundamental principle depicting the generalized ray formulation of optics provided by the Wigner function. This principle is formally identical to the Huygens-Fresnel principle but in terms of opposite concepts, rays instead of waves, and incoherent superpositions instead of coherent ones. This ray picture naturally includes diffraction and interference, and provides a geometrical picture of the degree of coherence

  7. Geometric optical transfer function and tis computation method

    International Nuclear Information System (INIS)

    Wang Qi


    Geometric Optical Transfer Function formula is derived after expound some content to be easily ignored, and the computation method is given with Bessel function of order zero and numerical integration and Spline interpolation. The method is of advantage to ensure accuracy and to save calculation

  8. A simple numerical model of a geometrically nonlinear Timoshenko beam

    NARCIS (Netherlands)

    Keijdener, C.; Metrikine, A.


    In the original problem for which this model was developed, onedimensional flexible objects interact through a non-linear contact model. Due to the non-linear nature of the contact model, a numerical time-domain approach was adopted. One of the goals was to see if the coupling between axial and

  9. A Novel Rational Design Method for Laminated Composite Structures Exhibiting Complex Geometrically Nonlinear Buckling Behaviour

    DEFF Research Database (Denmark)

    Lindgaard, Esben; Lund, Erik


    This paper presents a novel FEM-based approach for fiber angle optimal design of laminated composite structures exhibiting complicated nonlinear buckling behavior, thus enabling design of lighter and more cost-effective structures. The approach accounts for the geometrically nonlinear behavior of...

  10. Controlling geometric phase optically in a single spin in diamond (United States)

    Yale, Christopher G.

    Geometric phase, or Berry phase, is an intriguing quantum mechanical phenomenon that arises from the cyclic evolution of a quantum state. Unlike dynamical phases, which rely on the time and energetics of the interaction, the geometric phase is determined solely by the geometry of the path travelled in parameter space. As such, it is robust to certain types of noise that preserve the area enclosed by the path, and shows promise for the development of fault-tolerant logic gates. Here, we demonstrate the optical control of geometric phase within a solid-state spin qubit, the nitrogen-vacancy center in diamond. Using stimulated Raman adiabatic passage (STIRAP), we evolve a coherent dark state along `tangerine slice' trajectories on the Bloch sphere and probe these paths through time-resolved state tomography. We then measure the accumulated geometric phase through phase reference to a third ground spin state. In addition, we examine the limits of this control due to adiabatic breakdown as well as the longer timescale effect of far-detuned optical fields. Finally, we intentionally introduce noise into the experimental control parameters, and measure the distributions of the resulting phases to probe the resilience of the phase to differing types of noise. We also examine this robustness as a function of traversal time as well as the noise amplitude. Through these studies, we demonstrate that geometric phase is a promising route toward fault-tolerant quantum information processing. This work is supported by the AFOSR, the NSF, and the German Research Foundation.

  11. An introduction to geometric theory of fully nonlinear parabolic equations

    International Nuclear Information System (INIS)

    Lunardi, A.


    We study a class of nonlinear evolution equations in general Banach space being an abstract version of fully nonlinear parabolic equations. In addition to results of existence, uniqueness and continuous dependence on the data, we give some qualitative results about stability of the stationary solutions, existence and stability of the periodic orbits. We apply such results to some parabolic problems arising from combustion theory. (author). 24 refs

  12. Nonlinear dynamics of the bimodal optical computer (United States)

    Caulfield, H. John


    In the bimodal optical computer, linear and nonlinear acts occur in rapid succession generating solutions to Ax equals b. Both chaos and stochastic resonance can appear in some cases. This is the first observation of such complexity effects in optical processors.

  13. Geometrical nonlinear free vibration of multi-layered graphene sheets

    International Nuclear Information System (INIS)

    Wang Jinbao; He Xiaoqiao; Kitipornchai, S; Zhang Hongwu


    A nonlinear continuum model is developed for the nonlinear vibration analysis of multi-layered graphene sheets (MLGSs), in which the nonlinear van der Waals (vdW) interaction between any two layers is formulated explicitly. The nonlinear equations of motion are studied by the harmonic-balance methods. Based on the present model, the nonlinear stiffened amplitude-frequency relations of double-layered graphene sheets (DLGSs) are investigated in the spectral neighbourhood of lower frequencies. The influence of the vdW interaction on the vibration properties of DLGSs is well illustrated by plotting the resulting modes' shapes, in which in-phase and anti-phase vibrations of DLGSs are studied. In particular, the large-amplitude vibration which associates with the anti-phase resonant frequencies, separating DLGS into single-layered GSs, is a promising application that needs to be explored further. In contrast, the vibration modes that are associated with the resonant frequencies are nonidentical and give various vibration patterns, which indicates that MLGSs are highly suited to being used as high-frequency resonators.

  14. Optical rogue waves and soliton turbulence in nonlinear fibre optics

    DEFF Research Database (Denmark)

    Genty, G.; Dudley, J. M.; de Sterke, C. M.


    We examine optical rogue wave generation in nonlinear fibre propagation in terms of soliton turbulence. We show that higher-order dispersion is sufficient to generate localized rogue soliton structures, and Raman scattering effects are not required.......We examine optical rogue wave generation in nonlinear fibre propagation in terms of soliton turbulence. We show that higher-order dispersion is sufficient to generate localized rogue soliton structures, and Raman scattering effects are not required....

  15. Geometrically Nonlinear Static Analysis of 3D Trusses Using the Arc-Length Method (United States)

    Hrinda, Glenn A.


    Rigorous analysis of geometrically nonlinear structures demands creating mathematical models that accurately include loading and support conditions and, more importantly, model the stiffness and response of the structure. Nonlinear geometric structures often contain critical points with snap-through behavior during the response to large loads. Studying the post buckling behavior during a portion of a structure's unstable load history may be necessary. Primary structures made from ductile materials will stretch enough prior to failure for loads to redistribute producing sudden and often catastrophic collapses that are difficult to predict. The responses and redistribution of the internal loads during collapses and possible sharp snap-back of structures have frequently caused numerical difficulties in analysis procedures. The presence of critical stability points and unstable equilibrium paths are major difficulties that numerical solutions must pass to fully capture the nonlinear response. Some hurdles still exist in finding nonlinear responses of structures under large geometric changes. Predicting snap-through and snap-back of certain structures has been difficult and time consuming. Also difficult is finding how much load a structure may still carry safely. Highly geometrically nonlinear responses of structures exhibiting complex snap-back behavior are presented and analyzed with a finite element approach. The arc-length method will be reviewed and shown to predict the proper response and follow the nonlinear equilibrium path through limit points.

  16. A Circumzenithal Arc to Study Optics Concepts with Geometrical Optics (United States)

    Isik, Hakan


    This paper describes the formation of a circumzenithal arc for the purpose of teaching light and optics. A circumzenithal arc, an optic formation rarely witnessed by people, is formed in this study using a water-filled cylindrical glass illuminated by sunlight. Sunlight refracted at the top and side surfaces of the glass of water is dispersed into…

  17. Fundamentals of nonlinear optical materials

    Indian Academy of Sciences (India)

    Optical solitons, optical switching and memory by NLO effects, which depend on light intensity, are expected to result in the realization of pivotal .... The term squeezing refers to the generation of special states of electromagnetic fields in which noises are reduced to that below the quantum noise level. This is in accor-.

  18. Nonlinear optical techniques for surface studies

    International Nuclear Information System (INIS)

    Shen, Y.R.


    Recent effort in developing nonlinear optical techniques for surface studies is reviewed. Emphasis is on monolayer detection of adsorbed molecules on surfaces. It is shown that surface coherent antiStokes Raman scattering (CARS) with picosecond pulses has the sensitivity of detecting submonolayer of molecules. On the other hand, second harmonic or sum-frequency generation is also sensitive enough to detect molecular monolayers. Surface-enhanced nonlinear optical effects on some rough metal surfaces have been observed. This facilitates the detection of molecular monolayers on such surfaces, and makes the study of molecular adsorption at a liquid-metal interface feasible. Advantages and disadvantages of the nonlinear optical techniques for surface studies are discussed

  19. Nonlinear Optics with 2D Layered Materials. (United States)

    Autere, Anton; Jussila, Henri; Dai, Yunyun; Wang, Yadong; Lipsanen, Harri; Sun, Zhipei


    2D layered materials (2DLMs) are a subject of intense research for a wide variety of applications (e.g., electronics, photonics, and optoelectronics) due to their unique physical properties. Most recently, increasing research efforts on 2DLMs are projected toward the nonlinear optical properties of 2DLMs, which are not only fascinating from the fundamental science point of view but also intriguing for various potential applications. Here, the current state of the art in the field of nonlinear optics based on 2DLMs and their hybrid structures (e.g., mixed-dimensional heterostructures, plasmonic structures, and silicon/fiber integrated structures) is reviewed. Several potential perspectives and possible future research directions of these promising nanomaterials for nonlinear optics are also presented. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Material characterisation with methods of nonlinear optics (United States)

    Prylepa, A.; Reitböck, C.; Cobet, M.; Jesacher, A.; Jin, X.; Adelung, R.; Schatzl-Linder, M.; Luckeneder, G.; Stellnberger, K.-H.; Steck, T.; Faderl, J.; Stehrer, T.; Stifter, D.


    In this review, we present nonlinear optical methods, based on the second and third order nonlinear polarization, especially in the context of material characterization tasks outside the area of life sciences—for which these techniques are mostly designed. An overview of application studies reported to date is given, together with a discussion on the advantages and limits of the individual methods. Furthermore, new ways of experimentally combining different optical concepts are introduced, and their potential for characterisation and inspection tasks is evaluated in the context of various case studies, including the investigation of semiconductor surfaces, metals and related corrosion products, as well as of organic materials.

  1. Optical computation based on nonlinear total reflectional optical ...

    Indian Academy of Sciences (India)

    A new scheme of binary half adder and full adder is proposed. It realizes a kind of all-optical computation which is based on the polarization coding technique and the nonlinear total reflectional optical switches. Author Affiliations. Jianqi Zhang1 Huan Xu2. Laboratory of Photonic Information Technology, School of ...

  2. MERTIS: geometrical calibration of thermal infrared optical system by applying diffractive optical elements (United States)

    Bauer, M.; Baumbach, D.; Buder, M.; Börner, A.; Grießbach, D.; Peter, G.; Santier, E.; Säuberlich, T.; Schischmanow, A.; Schrader, S.; Walter, I.


    Geometrical sensor calibration is essential for space applications based on high accuracy optical measurements, in this case for the thermal infrared push-broom imaging spectrometer MERTIS. The goal is the determination of the interior sensor orientation. A conventional method is to measure the line of sight for a subset of pixels by single pixel illumination with collimated light. To adjust angles, which define the line of sight of a pixel, a manipulator construction is used. A new method for geometrical sensor calibration is using Diffractive Optical Elements (DOE) in connection with laser beam equipment. Diffractive optical elements (DOE) are optical microstructures, which are used to split an incoming laser beam with a dedicated wavelength into a number of beams with well-known propagation directions. As the virtual sources of the diffracted beams are points at infinity, the resulting image is invariant against translation. This particular characteristic allows a complete geometrical sensor calibration with only one taken image avoiding complex adjustment procedures, resulting in a significant reduction of calibration effort. We present a new method for geometrical calibration of a thermal infrared optical system, including an thermal infrared test optics and the MERTIS spectrometer bolometer detector. The fundamentals of this new approach for geometrical infrared optical systems calibration by applying diffractive optical elements and the test equipment are shown.

  3. Geometrical optical transfer function: is it worth calculating? (United States)

    Díaz, José A; Mahajan, Virendra N


    In this paper, we explore the merit of calculating the geometrical optical transfer function (GOTF) in optical design by comparing the time to calculate it with the time to calculate the diffraction optical transfer function (DOTF). We determine the DOTF by numerical integration of the pupil function autocorrelation (that reduces to an integration of a complex exponential of the aberration difference function), 2D digital autocorrelation of the pupil function, and the Fourier transform (FT) of the point-spread function (PSF); and we determine the GOTF by the FT of the geometrical PSF (that reduces to an integration over the pupil plane of a complex exponential that is a scalar product of the spatial frequency and transverse ray aberration vectors) and the FT of the spot diagram. Our starting point for calculating the DOTF is the wave aberrations of the system in its pupil plane, and the transverse ray aberrations in the image plane for the GOTF. Numerical results for primary aberrations and some typical imaging systems show that the direct numerical integrations are slow, but the GOTF calculation by a FT of the spot diagram is two or even three times slower than the DOTF calculation by an FT of the PSF, depending on the aberration. We conclude that the calculation of GOTF is, at best, an approximation of the DOTF and only for large aberrations; GOTF does not offer any advantage in the optical design process, and hence negates its utility.

  4. Nonlinear microstructured polymer optical fibres

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch

    is potentially the case for microstructured polymer optical fibres (mPOFs). Another advantage is that polymer materials have a higher biocompatibility than silica, meaning that it is easier to bond certain types of biosensor materials to a polymer surface than to silica. As with silica PCFs, it is difficult...

  5. Picosecond optical nonlinearities in symmetrical and unsymmetrical ...

    Indian Academy of Sciences (India)

    We present our experimental results on the picosecond nonlinear optical. (NLO) studies of symmetrical and unsymmetrical phthalocyanines, examined using the. Z-scan technique. Both the open-aperture ... Z-scan measurements were performed using the amplified Ti:sapphire laser system. (LEGEND, Coherent) delivering ...

  6. Modelling Nonlinear Optics in the CERN SPS

    CERN Document Server

    Zimmermann, Frank; Faus-Golfe, A; Collier, Paul


    Nonlinear fields arising from eddy currents in the vac-uum chamber and remanent fields in the magnets of the CERN SPS vary with time and with the acceleration cycle. We describe a procedure of constructing a nonlinear op-tics model for the SPS, by considering sextupolar, octupo-lar, and decapolar field errors in the dipole and quadrupole magnets, respectively, whose strengths are adjusted so as to best reproduce the measured nonlinear chromaticities up to third order in the momentum deviation. Applying this procedure to SPS chromaticity measurements taken at 26 GeV/c, we have obtained a refined optics model. The tune shifts with the transverse amplitude predicted by this model are consistent with a direct measurement.

  7. Geometric Nonlinear Computation of Thin Rods and Shells (United States)

    Grinspun, Eitan


    We develop simple, fast numerical codes for the dynamics of thin elastic rods and shells, by exploiting the connection between physics, geometry, and computation. By building a discrete mechanical picture from the ground up, mimicking the axioms, structures, and symmetries of the smooth setting, we produce numerical codes that not only are consistent in a classical sense, but also reproduce qualitative, characteristic behavior of a physical system----such as exact preservation of conservation laws----even for very coarse discretizations. As two recent examples, we present discrete computational models of elastic rods and shells, with straightforward extensions to the viscous setting. Even at coarse discretizations, the resulting simulations capture characteristic geometric instabilities. The numerical codes we describe are used in experimental mechanics, cinema, and consumer software products. This is joint work with Miklós Bergou, Basile Audoly, Max Wardetzky, and Etienne Vouga. This research is supported in part by the Sloan Foundation, the NSF, Adobe, Autodesk, Intel, the Walt Disney Company, and Weta Digital.

  8. RADIANCE AND PHOTON NOISE: Imaging in geometrical optics, physical optics, quantum optics and radiology. (United States)

    Barrett, Harrison H; Myers, Kyle J; Caucci, Luca


    A fundamental way of describing a photon-limited imaging system is in terms of a Poisson random process in spatial, angular and wavelength variables. The mean of this random process is the spectral radiance. The principle of conservation of radiance then allows a full characterization of the noise in the image (conditional on viewing a specified object). To elucidate these connections, we first review the definitions and basic properties of radiance as defined in terms of geometrical optics, radiology, physical optics and quantum optics. The propagation and conservation laws for radiance in each of these domains are reviewed. Then we distinguish four categories of imaging detectors that all respond in some way to the incident radiance, including the new category of photon-processing detectors. The relation between the radiance and the statistical properties of the detector output is discussed and related to task-based measures of image quality and the information content of a single detected photon.

  9. High field optical nonlinearities in gases (United States)

    Cheng, Yu-Hsiang

    Optical femtosecond self-channeling in gases, also called femtosecond filamentation, has become an important area of research in high field nonlinear optics. Filamentation occurs when laser light self-focuses in a gas owing to self-induced nonlinearity, and then defocuses in the plasma generated by the self-focused beam. The result of this process repeating itself multiple times is an extended region of plasma formation. Filamentation studies have been motivated by the extremely broad range of applications, especially in air, including pulse compression, supercontinuum generation, broadband high power terahertz pulse generation, discharge triggering and guiding, and remote sensing. Despite the worldwide work in filamentation, the fundamental gas nonlinearities governing self-focusing had never been directly measured in the range of laser intensity up to and including the ionization threshold. This dissertation presents the first such measurements. We absolutely measured the temporal refractive index change of O2, N2, Ar, H2, D2 and N2O caused by highfield ultrashort optical pulses with single-shot supercontinuum spectral interferometry, cleanly separating for the first time the instantaneous electronic and delayed rotational nonlinear response in diatomic gases. We conclusively showed that a recent claim by several European groups that the optical bound electron nonlinearity saturates and goes negative is not correct. Such a phenomenon would preclude the need for plasma to provide the defocusing contribution for filamentation. Our results show that the 'standard model of filamentation', where the defocusing is provided by plasma, is correct. Finally, we demonstrated that high repetition rate femtosecond laser pulses filamenting in gases can generate long-lived gas density `holes' which persist on millisecond timescales, long after the plasma has recombined. Gas density decrements up to ~20% have been measured. The density hole refilling is dominated by thermal

  10. Modal representation of geometrically nonlinear behavior by the finite element method

    International Nuclear Information System (INIS)

    Nagy, D.A.


    A method is presented for representing mild geometrically nonlinear static behavior of thin-type structures, within the finite element method, in terms of linear elastic and linear (bifurcation) buckling analysis results for structural loading or geometry situations which violate the idealized restrictive (perfect) interpretation of linear behavior up to bifurcation. (Auth.)

  11. Pushing the Boundaries : Level-set Methods and Geometrical Nonlinearities in Structural Topology Optimization

    NARCIS (Netherlands)

    Van Dijk, N.P.


    This thesis aims at understanding and improving topology optimization techniques focusing on density-based level-set methods and geometrical nonlinearities. Central in this work are the numerical modeling of the mechanical response of a design and the consistency of the optimization process itself.

  12. Anisotropic and nonlinear optical waveguides

    CERN Document Server

    Someda, CG


    Dielectric optical waveguides have been investigated for more than two decades. In the last ten years they have had the unique position of being simultaneously the backbone of a very practical and fully developed technology, as well as an extremely exciting area of basic, forefront research. Existing waveguides can be divided into two sets: one consisting of waveguides which are already in practical use, and the second of those which are still at the laboratory stage of their evolution. This book is divided into two separate parts: the first dealing with anisotropic waveguides, an

  13. Non-Reciprocal Geometric Wave Diode by Engineering Asymmetric Shapes of Nonlinear Materials (United States)

    Li, Nianbei; Ren, Jie


    Unidirectional nonreciprocal transport is at the heart of many fundamental problems and applications in both science and technology. Here we study the novel design of wave diode devices by engineering asymmetric shapes of nonlinear materials to realize the function of non-reciprocal wave propagations. We first show analytical results revealing that both nonlinearity and asymmetry are necessary to induce such non-reciprocal (asymmetric) wave propagations. Detailed numerical simulations are further performed for a more realistic geometric wave diode model with typical asymmetric shape, where good non-reciprocal wave diode effect is demonstrated. Finally, we discuss the scalability of geometric wave diodes. The results open a flexible way for designing wave diodes efficiently simply through shape engineering of nonlinear materials, which may find broad implications in controlling energy, mass and information transports. PMID:25169668

  14. A sandwich bar element for geometric nonlinear thermo-elastic analysis

    Directory of Open Access Journals (Sweden)

    Murín J.


    Full Text Available This contribution deals with a two-node straight sandwich composite bar element with constant double symmetric rectangular cross-sectional area. This new bar element (based on the non-linear second-order theory is intended to perform the non-incremental full geometric non-linear analysis. Stiffness matrix of this composite bar contains transfer constants, which accurately describe polynomial uniaxial variation of the material thermo-physical properties.In the numerical experiments the weak coupled thermo-structural geometric non-linear problem was solved. Obtained results were compared with several analyses made by ANSYS programme. Findings show good accuracy of this new finite element. The results obtained with this element do not depend on the element mesh density.

  15. Nonlinear optical response in narrow graphene nanoribbons (United States)

    Karimi, Farhad; Knezevic, Irena

    We present an iterative method to calculate the nonlinear optical response of armchair graphene nanoribbons (aGNRs) and zigzag graphene nanoribbons (zGNRs) while including the effects of dissipation. In contrast to methods that calculate the nonlinear response in the ballistic (dissipation-free) regime, here we obtain the nonlinear response of an electronic system to an external electromagnetic field while interacting with a dissipative environment (to second order). We use a self-consistent-field approach within a Markovian master-equation formalism (SCF-MMEF) coupled with full-wave electromagnetic equations, and we solve the master equation iteratively to obtain the higher-order response functions. We employ the SCF-MMEF to calculate the nonlinear conductance and susceptibility, as well as to calculate the dependence of the plasmon dispersion and plasmon propagation length on the intensity of the electromagnetic field in GNRs. The electron scattering mechanisms included in this work are scattering with intrinsic phonons, ionized impurities, surface optical phonons, and line-edge roughness. Unlike in wide GNRs, where ionized-impurity scattering dominates dissipation, in ultra-narrow nanoribbons on polar substrates optical-phonon scattering and ionized-impurity scattering are equally prominent. Support by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-SC0008712.

  16. Laser beam propagation in nonlinear optical media

    CERN Document Server

    Guha, Shekhar


    ""This is very unique and promises to be an extremely useful guide to a host of workers in the field. They have given a generalized presentation likely to cover most if not all situations to be encountered in the laboratory, yet also highlight several specific examples that clearly illustrate the methods. They have provided an admirable contribution to the community. If someone makes their living by designing lasers, optical parametric oscillators or other devices employing nonlinear crystals, or designing experiments incorporating laser beam propagation through linear or nonlinear media, then

  17. The Young-Laplace equation links capillarity with geometrical optics

    CERN Document Server

    Rodriguez-Valverde, M A; Hidalgo-Alvarez, R


    Analogies in physics are unusual coincidences that can be very useful to solve problems and to clarify some theoretical concepts. Apart from their own curiosity, analogies are attractive tools because they reduce the abstraction of some complex phenomena in such a way that these can be understood by means of other phenomena closer to daily experience. Usually, two analogous systems share a common aspect, like the movement of particles or transport of matter. On account of this, the analogy presented is exceptional since the involved phenomena are a priori disjoined. The most important equation of capillarity, the Young-Laplace equation, has the same structure as the Gullstrand equation of geometrical optics, which relates the optic power of a thick lens to its geometry and the properties of the media.

  18. Rigorous theory of molecular orientational nonlinear optics

    Directory of Open Access Journals (Sweden)

    Chong Hoon Kwak


    Full Text Available Classical statistical mechanics of the molecular optics theory proposed by Buckingham [A. D. Buckingham and J. A. Pople, Proc. Phys. Soc. A 68, 905 (1955] has been extended to describe the field induced molecular orientational polarization effects on nonlinear optics. In this paper, we present the generalized molecular orientational nonlinear optical processes (MONLO through the calculation of the classical orientational averaging using the Boltzmann type time-averaged orientational interaction energy in the randomly oriented molecular system under the influence of applied electric fields. The focal points of the calculation are (1 the derivation of rigorous tensorial components of the effective molecular hyperpolarizabilities, (2 the molecular orientational polarizations and the electronic polarizations including the well-known third-order dc polarization, dc electric field induced Kerr effect (dc Kerr effect, optical Kerr effect (OKE, dc electric field induced second harmonic generation (EFISH, degenerate four wave mixing (DFWM and third harmonic generation (THG. We also present some of the new predictive MONLO processes. For second-order MONLO, second-order optical rectification (SOR, Pockels effect and difference frequency generation (DFG are described in terms of the anisotropic coefficients of first hyperpolarizability. And, for third-order MONLO, third-order optical rectification (TOR, dc electric field induced difference frequency generation (EFIDFG and pump-probe transmission are presented.

  19. Geometric optical optimization of the corneal lens of Notonecta glauca. (United States)

    Horváth, G


    The optimal shape of the corneal lens of the water bug backswimmer (Notonecta glauca) and the optimal shape and position of the thin transition layer between the distal and proximal units of its cornea are theoretically determined. Using a geometric optical method, first the shape of a geometric interface between the lens units is determined, which eliminates the longitudinal spherical aberration. This interface is investigated for differently formed thick lenses when the medium in contact with the entrance surface of the lens is water or air. The optimal transition layer for the amphibious backswimmer is that, the boundaries of which are the theoretical interfaces for water and air, and the refractive index varies continuously in it. The optimal shape of the corneal lens is determined, with the disadvantageous lenses, with respect to the possible minimal spherical aberration and amount of reflected light from the transition layer, being rejected. The optimal position of the transition layer in the cornea can be obtained from the minimization of the amount of diffracted light on the marginal connection of the layers. The optimal corneal lens for backswimmer has ellipsoid boundary surfaces; the optimal transition layer in it is thin bell-shaped, at the marginal connection of which there is no dimple, the maximum of the layer is on the margin of the cornea. The shape of the theoretically optimal corneal lens, the shape and position of the theoretically optimal transition layer agree well with those of Notonecta glauca. The question posed, the geometric optical method used and the results presented are of general importance, and not only with respect to vision in the bug Notonecta, but also in the fossil trilobites, or in the wave guide theories which have been employed in similar modelling problems, in design of system of lenses without spherical aberration, for example.

  20. Quantum Nonlinear Optics in Optomechanical Nanoscale Waveguides. (United States)

    Zoubi, Hashem; Hammerer, Klemens


    We show that strong nonlinearities at the few photon level can be achieved in optomechanical nanoscale waveguides. We consider the propagation of photons in cm-scale one-dimensional nanophotonic structures where stimulated Brillouin scattering (SBS) is strongly enhanced by radiation pressure coupling. We introduce a configuration that allows slowing down photons by several orders of magnitude via SBS from sound waves using two pump fields. Slowly propagating photons can then experience strong nonlinear interactions through virtual off-resonant exchange of dispersionless phonons. As a benchmark we identify requirements for achieving a large cross-phase modulation among two counterpropagating photons applicable for photonic quantum gates. Our results indicate that strongly nonlinear quantum optics is possible in continuum optomechanical systems realized in nanophotonic structures.

  1. Dissipative soliton acceleration in nonlinear optical lattices. (United States)

    Kominis, Yannis; Papagiannis, Panagiotis; Droulias, Sotiris


    An effective mechanism for dissipative soliton acceleration in nonlinear optical lattices under the presence of linear gain and nonlinear loss is presented. The key idea for soliton acceleration consists of the dynamical reduction of the amplitude of the effective potential experienced by the soliton so that its kinetic energy eventually increases. This is possible through the dependence of the effective potential amplitude on the soliton mass, which can be varied due to the presence of gain and loss mechanisms. In contrast to the case where either the linear or the nonlinear refractive index is spatially modulated, we show that when both indices are modulated with the same period we can have soliton acceleration and mass increasing as well as stable soliton propagation with constant non-oscillating velocity. The acceleration mechanism is shown to be very robust for a wide range of configurations.

  2. Nonlinear thermal stability of geometrically imperfect shape memory alloy hybrid laminated composite plates (United States)

    Asadi, Hamed; Eynbeygi, Mehdi; Wang, Quan


    The instability of geometrically imperfect shape memory alloy (SMA) fibers reinforced with hybrid laminated composite (SMAHC) plates and subjected to a uniform thermal loading is analytically investigated. The material properties of the SMAHC plates are assumed to be functions of temperature. Nonlinear equations of the plates’ thermal stability are derived based on a higher order shear deformation theory incorporating von Karman geometrical nonlinearity via stationary potential energy. The structural recovery stress, which is generated by martensitic phase transformation of the prestrained SMA fibers, is calculated based on the one-dimensional thermodynamic constitutive model by Brinson. Adopting the Galerkin procedure, the governing nonlinear partial differential equations are converted into a set of nonlinear algebraic equations, in which systems of equations are solved by introducing an analytical approach. Closed-form formulations are presented to determine the load-deflection path and critical buckling temperature of the plate. Based on the developed closed-form solutions, ample numerical results are presented to provide an insight into the effects of the volume fraction, prestrain, location and orientation of the SMA fibers, composite plate geometry, geometrical imperfection and temperature dependence on the stability of the SMAHC plates. It is shown that a proper application of SMA fibers results in a considerable delay of the thermal bifurcation and controllable thermal post-buckling deflection of the SMAHC plate.

  3. Nonlinear optical studies of organic monolayers

    International Nuclear Information System (INIS)

    Shen, Y.R.


    Second-order nonlinear optical effects are forbidden in a medium with inversion symmetry, but are necessarily allowed at a surface where the inversion summary is broken. They are often sufficiently strong so that a submonolayer perturbation of the surface can be readily detected. They can therefore be used as effective tools to study monolayers adsorbed at various interfaces. We discuss here a number of recent experiments in which optical second harmonic generation (SHG) and sum-frequency generation (SFG) are employed to probe and characterize organic monolayers. 15 refs., 5 figs

  4. Atom lasers and nonlinear atom optics

    International Nuclear Information System (INIS)

    Deng Lu


    Two recent experimental breakthroughs in the field of atomic physics are reported: the realization of a well-collimated, widely tunable, quasi-continuous wave atom laser, and the generation of matter waves via coherent multi-wave mixing. The former is a critical step towards a continuous wave, high brightness atom laser while the latter has opened a new field of research: nonlinear atom optics

  5. Nonlinear optical polymers for electro-optic signal processing (United States)

    Lindsay, Geoffrey A.


    Photonics is an emerging technology, slated for rapid growth in communications systems, sensors, imagers, and computers. Its growth is driven by the need for speed, reliability, and low cost. New nonlinear polymeric materials will be a key technology in the new wave of photonics devices. Electron-conjubated polymeric materials offer large electro-optic figures of merit, ease of processing into films and fibers, ruggedness, low cost, and a plethora of design options. Several new broad classes of second-order nonlinear optical polymers were developed at the Navy's Michelson Laboratory at China Lake, California. Polar alignment in thin film waveguides was achieved by electric-field poling and Langmuir-Blodgett processing. Our polymers have high softening temperatures and good aging properties. While most of the films can be photobleached with ultraviolet (UV) light, some have excellent stability in the 500-1600 nm range, and UV stability in the 290-310 nm range. The optical nonlinear response of these polymers is subpicosecond. Electro-optic switches, frequency doublers, light modulators, and optical data storage media are some of the device applications anticipated for these polymers.

  6. Geometrically nonlinear vibration analysis of piezoelectrically actuated FGM plate with an initial large deformation

    Energy Technology Data Exchange (ETDEWEB)

    Naei, Mohammad Hassan; Rastgoo, Abbas [University of Tehran, Tehran (Iran, Islamic Republic of); Ebrahimi, Farzad [Faculty of Engineering and Technology, lmam Khomeini International University, Qazvin (Iran, Islamic Republic of)


    A theoretical model for geometrically nonlinear vibration analysis of piezoelectrically actuated circular plates made of functionally grade material (FGM) is presented based on Kirchhoff's-Love hypothesis with von-Karman type geometrical large nonlinear deformations. To determine the initial stress state and pre-vibration deformations of the smart plate a nonlinear static problem is solved followed by adding an incremental dynamic state to the pre-vibration state. The derived governing equations of the structure are solved by exact series expansion method combined with perturbation approach. The material properties of the FGM core plate are assumed to be graded in the thickness direction according to the power-law distribution in terms of the volume fractions of the constituents. Control of the FGM plate's nonlinear deflections and natural frequencies using high control voltages is studied and their nonlinear effects are evaluated. Numerical results for FG plates with various mixture of ceramic and metal are presented in dimensionless forms. In a parametric study the emphasis is placed on investigating the effect of varying the applied actuator voltage as well as gradient index of FGM plate on vibration characteristics of the smart structure

  7. A Novel Rational Design Method for Laminated Composite Structures Exhibiting Complex Geometrically Nonlinear Buckling Behaviour

    DEFF Research Database (Denmark)

    Lindgaard, Esben; Lund, Erik


    This paper presents a novel FEM-based approach for fiber angle optimal design of laminated composite structures exhibiting complicated nonlinear buckling behavior, thus enabling design of lighter and more cost-effective structures. The approach accounts for the geometrically nonlinear behavior...... of the structure by utilizing path tracing response analysis up until the buckling point. The method simultaneously includes loss of stability due to bifurcation and limiting behavior and thereby avoids problems related to mode or stability type switching during optimization. The optimization formulation...


    Directory of Open Access Journals (Sweden)

    Gil Rama


    Full Text Available Composite laminates consisting of passive and multi-functional materials represent a powerful material system. Passive layers could be made of isotropic materials or fiber-reinforced composites, while piezoelectric ceramics are considered here as a multi-functional material. The paper is focused on  linear and geometrically nonlinear dynamic analysis of smart structures made of such a material system. For this purpose, a linear 3-node shell element is used. It employs the Mindlin-Reissner kinematics and the discrete shear gap (DSG technique to alleviate the transverse shear locking effects. The electric potential is assumed to vary linearly through the thickness for each piezoelectric layer. A co-rotational formulation is used to handle the geometrically nonlinear effects. A number of examples involving actuator and sensor application of piezoelectric layers are considered. For the validation purposes, the results available in the literature and those computed in Abaqus are used as a reference.

  9. An efficient formulation for linear and geometric non-linear membrane elements

    Directory of Open Access Journals (Sweden)

    Mohammad Rezaiee-Pajand

    Full Text Available Utilizing the straingradient notation process and the free formulation, an efficient way of constructing membrane elements will be proposed. This strategy can be utilized for linear and geometric non-linear problems. In the suggested formulation, the optimization constraints of insensitivity to distortion, rotational invariance and not having parasitic shear error are employed. In addition, the equilibrium equations will be established based on some constraints among the strain states. The authors' technique can easily separate the rigid body motions, and those belong to deformational motions. In this article, a novel triangular element, named SST10, is formulated. This element will be used in several plane problems having irregular mesh and complicated geometry with linear and geometrically nonlinear behavior. The numerical outcomes clearly demonstrate the efficiency of the new formulation.

  10. Degenerated shell element for geometrically nonlinear analysis of thin-walled piezoelectric active structures

    International Nuclear Information System (INIS)

    Marinković, D; Köppe, H; Gabbert, U


    Active piezoelectric thin-walled structures, especially those with a notably higher membrane than bending stiffness, are susceptible to large rotations and transverse deflections. Recent investigations conducted by a number of researchers have shown that the predicted behavior of piezoelectric structures can be significantly influenced by the assumption of large displacements and rotations of the structure, thus demanding a geometrically nonlinear formulation in order to investigate it. This paper offers a degenerated shell element and a simplified formulation that relies on small incremental steps for the geometrically nonlinear analysis of piezoelectric composite structures. A set of purely mechanical static cases is followed by a set of piezoelectric coupled static cases, both demonstrating the applicability of the proposed formulation

  11. Optimal design of geometrically nonlinear shells of revolution with using the mixed finite element method (United States)

    Stupishin, L. U.; Nikitin, K. E.; Kolesnikov, A. G.


    The article is concerned with a methodology of optimal design of geometrically nonlinear (flexible) shells of revolution of minimum weight with strength, stability and strain constraints. The problem of optimal design with constraints is reduced to the problem of unconstrained minimization using the penalty functions method. Stress-strain state of shell is determined within the geometrically nonlinear deformation theory. A special feature of the methodology is the use of a mixed finite-element formulation based on the Galerkin method. Test problems for determining the optimal form and thickness distribution of a shell of minimum weight are considered. The validity of the results obtained using the developed methodology is analyzed, and the efficiency of various optimization algorithms is compared to solve the set problem. The developed methodology has demonstrated the possibility and accuracy of finding the optimal solution.

  12. Modal representation of geometrically nonlinear behavior by the finite element method

    International Nuclear Information System (INIS)

    Nagy, D.A.


    A method is presented for representing mild geometrically nonlinear static behavior of thin-type structures, within the finite element method, in terms of linear elastic and linear (bifurcation) buckling analysis results for structural loading or geometry situations which violate the idealized restrictive (perfect) interpretation of linear behavior up to bifurcation. Formulation of the finite element displacement method for material linearity but retaining the full, nonlinear strain-displacement relations (geometric nonlinearity) leads to highly nonlinear equations relating the unknown nodal generalized displacements r to the applied loading R. Restriction to small strains alone does not linearize these equations for thin-type structural configurations; only explicitly requiring that all products of displacement gadients be much smaller than the gadients themselves reduces the equations to the familiar linear form Ksub(e)r=R, where Ksub(e) is the elastic stiffness. Assuming then that the solutions r of the linear equations also satisfies the full nonlinear equations (i.e., that the above explicit requirement is satisfied), a second solution to the full equations can be sought for a one-parameter loading path lambdaR, leading to the well-known linear (bifurcation) buckling eigenvalue problem Ksub(e)X=-Ksub(g)XΛ where Ksub(g) is the geometric stiffness, X the matrix whose columns are the eigenvectors (so-called buckling mode shapes) and Λ is a diagonal matrix of eigenvalues lambda(i) (so-called load scale factors). From the viewpoint of the practising structural analyst using finite element software, the method presented here gives broader and deeper significance to an existing linear (bifurcation) buckling analysis capability, in that the additional computations are minimal beyond those already required for a linear static and buckling analysis, and should be easily performable within any well-designed general purpose finite element system

  13. Advanced in Nonlinear Optics and Laser Research and Development

    International Nuclear Information System (INIS)

    Jackel, S.; Kotler, Z; Lavi, R.; Sternklar, S.


    The Nonlinear Optics Group (NLOG) at Soreq NRC is engaged in the development of fundamental and applied technology in the related fields of nonlinear optics and laser development. Our work in nonlinear optics started with the goal of improving laser performance. These efforts were successful and opened the way for R and D in nonlinear optics for other applications. Today we use nonlinear optics to enable continuous tunability of lasers, control the path of light beams, modulate a light signal rapidly, provide optical data storage, and supply new means of microscopically probing biological and inorganic samples. Technology maturation and interaction with users will show which aspects of nonlinear optics will make the most impact

  14. A refined element-based Lagrangian shell element for geometrically nonlinear analysis of shell structures

    Directory of Open Access Journals (Sweden)

    Woo-Young Jung


    Full Text Available For the solution of geometrically nonlinear analysis of plates and shells, the formulation of a nonlinear nine-node refined first-order shear deformable element-based Lagrangian shell element is presented. Natural co-ordinate-based higher order transverse shear strains are used in present shell element. Using the assumed natural strain method with proper interpolation functions, the present shell element generates neither membrane nor shear locking behavior even when full integration is used in the formulation. Furthermore, a refined first-order shear deformation theory for thin and thick shells, which results in parabolic through-thickness distribution of the transverse shear strains from the formulation based on the third-order shear deformation theory, is proposed. This formulation eliminates the need for shear correction factors in the first-order theory. To avoid difficulties resulting from large increments of the rotations, a scheme of attached reference system is used for the expression of rotations of shell normal. Numerical examples demonstrate that the present element behaves reasonably satisfactorily either for the linear or for geometrically nonlinear analysis of thin and thick plates and shells with large displacement but small strain. Especially, the nonlinear results of slit annular plates with various loads provided the benchmark to test the accuracy of related numerical solutions.

  15. Geometrically Nonlinear Static Analysis of Edge Cracked Timoshenko Beams Composed of Functionally Graded Material

    Directory of Open Access Journals (Sweden)

    Şeref Doğuşcan Akbaş


    Full Text Available Geometrically nonlinear static analysis of edge cracked cantilever Timoshenko beams composed of functionally graded material (FGM subjected to a nonfollower transversal point load at the free end of the beam is studied with large displacements and large rotations. Material properties of the beam change in the height direction according to exponential distributions. The cracked beam is modeled as an assembly of two subbeams connected through a massless elastic rotational spring. In the study, the finite element of the beam is constructed by using the total Lagrangian Timoshenko beam element approximation. The nonlinear problem is solved by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. The convergence study is performed for various numbers of finite elements. In the study, the effects of the location of crack, the depth of the crack, and various material distributions on the nonlinear static response of the FGM beam are investigated in detail. Also, the difference between the geometrically linear and nonlinear analysis of edge cracked FGM beam is investigated in detail.

  16. Free vibration of geometrically nonlinear micro-switches under electrostatic and Casimir forces

    International Nuclear Information System (INIS)

    Jia, X L; Kitipornchai, S; Lim, C W; Yang, J


    This paper investigates the free vibration characteristics of micro-switches under combined electrostatic, intermolecular forces and axial residual stress, with an emphasis on the effect of geometric nonlinear deformation due to mid-plane stretching and the influence of Casimir force. The micro-switch considered in this study is made of either homogeneous material or non-homogeneous functionally graded material with two material phases. The Euler–Bernoulli beam theory with von Karman type nonlinear kinematics is applied in the theoretical formulation. The principle of virtual work is used to derive the nonlinear governing differential equation. The eigenvalue problem which describes free vibration of the micro-beam at its statically deflected state is then solved using the differential quadrature method. The natural frequencies and mode shapes of micro-switches for four different boundary conditions (i.e. clamped–clamped, clamped–simply supported, simply supported and clamped–free) are obtained. The solutions are validated through direct comparisons with experimental and other existing results reported in previous studies. A parametric study is conducted to show the significant effects of geometric nonlinearity, Casimir force, axial residual stress and material composition for the natural frequencies

  17. Progress in nonlinear nano-optics

    CERN Document Server

    Lienau, Christoph; Grunwald, Rüdiger


    This book presents the state of the art in nonlinear nanostructures for ultrafast laser applications. Most recent results in two emerging fields are presented: (i) generation of laser-induced nanostructures in materials like metals, metal oxides and semiconductors, and (ii) ultrafast excitation and energy transfer in nanoscale physical, chemical and hybrid systems. Particular emphasis is laid on the up-to-date controversially discussed mechanisms of sub-wavelength ripple formation including models of self-organized material transport and multiphoton excitation channels, nonlinear optics of plasmonic structures (nanotips, nanowires, 3D-metamaterials), and energy localization and transport on ultrafast time scale and spatial nanoscale. High-resolution spectroscopy, simulation and characterization techniques are reported. New applications of ultrashort-pulsed lasers for materials processing and the use of nanostructured materials for characterizing laser fields and laser-matter-interactions are discussed.

  18. Quantum Information Processing using Nonlinear Optical Effects

    DEFF Research Database (Denmark)

    Andersen, Lasse Mejling

    This PhD thesis treats applications of nonlinear optical effects for quantum information processing. The two main applications are four-wave mixing in the form of Bragg scattering (BS) for quantum-state-preserving frequency conversion, and sum-frequency generation (SFG) in second-order nonlinear...... materials for heralded entanglement. BS is shown to be separable in the input and output modes in the low-conversion regime, the regime of small pump powers or short interaction times. The selective frequency conversion of a signal is found to only depend on one of the pumps, while the temporal output...... shifts of the input and output modes, corresponding to shifts of the central frequencies of the fields. The trade-off is that one is only able to select which signals are converted, or change the shape of the output idler. Finally, entanglement swapping using SFG was investigated. Considering two pairs...

  19. Uncertainty in visual processes predicts geometrical optical illusions. (United States)

    Fermüller, Cornelia; Malm, Henrik


    It is proposed in this paper that many geometrical optical illusions, as well as illusory patterns due to motion signals in line drawings, are due to the statistics of visual computations. The interpretation of image patterns is preceded by a step where image features such as lines, intersections of lines, or local image movement must be derived. However, there are many sources of noise or uncertainty in the formation and processing of images, and they cause problems in the estimation of these features; in particular, they cause bias. As a result, the locations of features are perceived erroneously and the appearance of the patterns is altered. The bias occurs with any visual processing of line features; under average conditions it is not large enough to be noticeable, but illusory patterns are such that the bias is highly pronounced. Thus, the broader message of this paper is that there is a general uncertainty principle which governs the workings of vision systems, and optical illusions are an artifact of this principle.

  20. Geometrically Nonlinear Shell Analysis of Wrinkled Thin-Film Membranes with Stress Concentrations (United States)

    Tessler, Alexander; Sleight, David W.


    Geometrically nonlinear shell finite element analysis has recently been applied to solar-sail membrane problems in order to model the out-of-plane deformations due to structural wrinkling. Whereas certain problems lend themselves to achieving converged nonlinear solutions that compare favorably with experimental observations, solutions to tensioned membranes exhibiting high stress concentrations have been difficult to obtain even with the best nonlinear finite element codes and advanced shell element technology. In this paper, two numerical studies are presented that pave the way to improving the modeling of this class of nonlinear problems. The studies address the issues of mesh refinement and stress-concentration alleviation, and the effects of these modeling strategies on the ability to attain converged nonlinear deformations due to wrinkling. The numerical studies demonstrate that excessive mesh refinement in the regions of stress concentration may be disadvantageous to achieving wrinkled equilibrium states, causing the nonlinear solution to lock in the membrane response mode, while totally discarding the very low-energy bending response that is necessary to cause wrinkling deformation patterns.

  1. Study of research-based teaching mode in the course of Geometric Optics and Optical Instruments (United States)

    Wang, Zefeng; Geng, Meihua; Cheng, Xiangai; Jiang, Zongfu


    Modern teaching opinions require research-based teaching mode in research universities. It is an advanced teaching mode enabling students to explore science and technology autonomously. It has a lot of advantages comparing with the conventional knowledge-oriented teaching mode. In this paper, we show some understanding of research-based teaching mode. And based on the course features of Geometric optics and optical instruments and characteristics of students, we explore the research-based teaching mode in the part of Practical Optical Systems.

  2. Computational studies of third-order nonlinear optical properties of ...

    Indian Academy of Sciences (India)


    Jun 20, 2017 ... We have reported a theoretical investigation on nonlinear optical behaviour, electronic and optical properties and other molecular properties of the organic nonlinear optical crystal 2-aminopyridinium ptoluenesulphonate(APPTS). The computation has been done using density functional theory (DFT) ...

  3. Nonlinear optical THz generation and sensing applications (United States)

    Kawase, Kodo


    We have suggested a wide range of real-life applications using novel terahertz imaging techniques. A high-resolution terahertz tomography was demonstrated by ultra short terahertz pulses using optical fiber and a nonlinear organic crystal. We also report on the thickness measurement of very thin films using high-sensitivity metal mesh filter. Further we have succeeded in a non-destructive inspection that can monitor the soot distribution in the ceramic filter using millimeter-to-terahertz wave computed tomography. These techniques are directly applicable to the non-destructive testing in industries.

  4. Enhancement of optical nonlinearities with stationary light

    DEFF Research Database (Denmark)

    Iakoupov, Ivan

    Stationary light arises in atomic ensembles with certain energy level configurations, when two counter-propagating classical drives (lasers) are applied. Probe light coupled to a different energy level transition than the classical drives can be completely stopped, while still retaining its light...... character. We will be interested in the regime of stationary light, where the probe light still propagates through the atomic ensemble, but extremely slowly. In other words, probe field has a very low group velocity, which increases its interaction time with any optical nonlinearity. The enhancement...

  5. Nonlinear Optics in AlGaAs on Insulator

    DEFF Research Database (Denmark)

    Pu, Minhao; Ottaviano, Luisa; Semenova, Elizaveta


    AlGaAs on insulator is a powerful nonlinear platform sporting a high effective nonlinearity and the possibility to fabricate complex designs. We will present low loss waveguides enabling efficient optical signal processing and Kerr comb generation.......AlGaAs on insulator is a powerful nonlinear platform sporting a high effective nonlinearity and the possibility to fabricate complex designs. We will present low loss waveguides enabling efficient optical signal processing and Kerr comb generation....

  6. Unidirectional transmission in 1D nonlinear photonic crystal based on topological phase reversal by optical nonlinearity


    Chong Li; Xiaoyong Hu; Hong Yang; Qihuang Gong


    We propose a scheme of unidirectional transmission in a 1D nonlinear topological photonic crystal based on the topological edge state and three order optical nonlinearity. The 1D photonic crystals consists of a nonlinear photonic crystal L and a linear photonic crystal R. In the backward direction, light is totally reflected for the photons transmission prohibited by the bandgap. While in the forward direction, light interacts with the nonlinear photonic crystal L by optical Kerr effect, brin...

  7. A Wave-Optics Approach to Paraxial Geometrical Laws Based on Continuity at Boundaries (United States)

    Linares, J.; Nistal, M. C.


    We present a derivation of the paraxial geometrical laws starting from a wave-optics approach, in particular by using simple continuity conditions of paraxial spherical waves at boundaries (discontinuities) between optical media. Paraxial geometrical imaging and magnification laws, under refraction and reflection at boundaries, are derived for…

  8. The Quest for the Ultimate Nonlinear Optical Material (United States)

    Dagenais, M.


    The following sections are included: * Introduction * From Infancy to the Real World * Highly Efficient Nonlinear Optical Materials for Switching and Processing * The Era of Pragmatism * Conclusion * References

  9. Integration of Geometrical and Material Nonlinear Energy Sink with Piezoelectric Material Energy Harvester

    Directory of Open Access Journals (Sweden)

    Ye-Wei Zhang


    Full Text Available This paper presents a novel design by integrating geometrical and material nonlinear energy sink (NES with a piezoelectric-based vibration energy harvester under shock excitation, which can realize vibration control and energy harvesting. The nonlinear spring and hysteresis behavior of the NES could reflect geometrical and material nonlinearity, respectively. Two configurations of the piezoelectric device, including the piezoelectric element embedded between the NES mass and the single-degree-of-freedom system or ground, are utilised to examine the energy dissipated by damper and hysteresis behavior of NES and the energy harvested by the piezoelectric element. Similar numerical research methods of Runge-Kutta algorithm are used to investigate the two configurations. The energy transaction measure (ETM is adopted to examine the instantaneous energy transaction between the primary and the NES-piezoelectricity system. And it demonstrates that the dissipated and harvested energy transaction is transferred from the primary system to the NES-piezoelectricity system and the instantaneous transaction of mechanical energy occupies a major part of the energy of transaction. Both figurations could realize vibration control efficiently.


    Directory of Open Access Journals (Sweden)

    Ayad A. Abdul -Razzak


    Full Text Available In the present study a nonlinear finite element analysis is presented  to predict the fire resistance of reinforced concrete slabs at fire environment. An eight node layered degenerated shell element utilizing Mindlin/Reissner thick plate theory is employed. The proposed model considered cracking, crushing and yielding of concrete and steel at elevated temperatures. The layered approach is used to represent the steel reinforcement and discretize the concrete slab through the thickness. The reinforcement steel is represented as a smeared layer of equivalent thickness with uniaxial strength and rigidity properties.Geometric nonlinear analysis may play an important role in the behavior of reinforced concrete slabs at high temperature. Geometrical nonlinearity in the layered approach is considered in the mathematical model, which is based on the total Lagrangian approach taking into account Von Karman assumptions.Finally two examples for which experimental results are available are analyzed, using the proposed model .The comparison showed good agreement with experimental results. 

  11. Geometric method for stability of non-linear elastic thin shells

    CERN Document Server

    Ivanova, Jordanka


    PREFACE This book deals with the new developments and applications of the geometric method to the nonlinear stability problem for thin non-elastic shells. There are no other published books on this subject except the basic ones of A. V. Pogorelov (1966,1967,1986), where variational principles defined over isometric surfaces, are postulated, and applied mainly to static and dynamic problems of elastic isotropic thin shells. A. V. Pogorelov (Harkov, Ukraine) was the first to provide in his monographs the geometric construction of the deformed shell surface in a post-critical stage and deriving explicitely the asymptotic formulas for the upper and lower critical loads. In most cases, these formulas were presented in a closed analytical form, and confirmed by experimental data. The geometric method by Pogorelov is one of the most important analytical methods developed during the last century. Its power consists in its ability to provide a clear geometric picture of the postcritical form of a deformed shell surfac...

  12. Different optical properties in different periodic slot cavity geometrical morphologies (United States)

    Zhou, Jing; Shen, Meng; Du, Lan; Deng, Caisong; Ni, Haibin; Wang, Ming


    In this paper, optical properties of two-dimensional periodic annular slot cavity arrays in hexagonal close-packing on a silica substrate are theoretically characterized by finite difference time domain (FDTD) simulation method. By simulating reflectance spectra, electric field distribution, and charge distribution, we confirm that multiple cylindrical surface plasmon resonances can be excited in annular inclined slot cavities by linearly polarized light, in which the four reflectance dips are attributed to Fabry-Perot cavity resonances in the coaxial cavity. A coaxial waveguide mode TE11 will exist in these annular cavities, and the wavelengths of these reflectance dips are effectively tailored by changing the geometrical pattern of slot cavity and the dielectric materials filled in the cavities. These resonant wavelengths are localized in annular cavities with large electric field enhancement and dissipate gradually due to metal loss. The formation of an absorption peak can be explained from the aspect of phase matching conditions. We observed that the proposed structure can be tuned over the broad spectral range of 600-4000 nm by changing the outer and inner radii of the annular gaps, gap surface topography. Meanwhile, different lengths of the cavity may cause the shift of resonance dips. Also, we study the field enhancement at different vertical locations of the slit. In addition, dielectric materials filling in the annular gaps will result in a shift of the resonance wavelengths, which make the annular cavities good candidates for refractive index sensors. The refractive index sensitivity of annular cavities can also be tuned by the geometry size and the media around the cavity. Annular cavities with novel applications can be implied as surface enhanced Raman spectra substrates, refractive index sensors, nano-lasers, and optical trappers. Project supported by the National Natural Science Foundation of China (Grant No. 61178044), the Natural Science Foundation

  13. Non-linear optical imaging – Introduction and pharmaceutical applications

    NARCIS (Netherlands)

    Fussell, A.L.; Isomaki, Antti; Strachan, Clare J.


    Nonlinear optical imaging is an emerging technology with much potential in pharmaceutical analysis. The technique encompasses a range of optical phenomena, including coherent anti-Stokes Raman scattering (CARS), second harmonic generation (SHG), and twophoton excited fluorescence (TPEF). The

  14. Non-Reciprocal Geometric Wave Diode by Engineering Asymmetric Shapes of Nonlinear Materials

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Jie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Li, Nianbei [Tongji Univ., Shanghai Shi (China)


    Unidirectional nonreciprocal transport is at the heart of many fundamental problems and applications in both science and technology. Here we study how to design the novel wave diode devices to realize the non-reciprocal wave propagations. Analytical results reveal that such non-reciprocal wave propagation can be purely induced by asymmetric geometry in nonlinear materials. The detailed numerical simulations are performed for a more realistic geometric wave diode model with typical asymmetric shape, where good non-reciprocal wave diode effect has been demonstrated. The results open a way for making wave diodes efficiently simply through shape engineering.

  15. Optical Chirality in Nonlinear Optics: Application to High Harmonic Generation (United States)

    Neufeld, Ofer; Cohen, Oren


    Optical chirality (OC)—one of the fundamental quantities of electromagnetic fields—corresponds to the instantaneous chirality of light. It has been utilized for exploring chiral light-matter interactions in linear optics, but has not yet been applied to nonlinear processes. Motivated to explore the role of OC in the generation of helically polarized high-order harmonics and attosecond pulses, we first separate the OC of transversal and paraxial beams to polarization and orbital terms. We find that the polarization-associated OC of attosecond pulses corresponds approximately to that of the pump in the quasimonochromatic case, but not in the multichromatic pump cases. We associate this discrepancy with the fact that the polarization OC of multichromatic pumps vary rapidly in time along the optical cycle. Thus, we propose new quantities, noninstantaneous polarization-associated OC, and time-scale-weighted polarization-associated OC, and show that these quantities link the chirality of multichromatic pumps and their generated attosecond pulses. The presented extension to OC theory should be useful for exploring various nonlinear chiral light-matter interactions. For example, it stimulates us to propose a tricircular pump for generation of highly elliptical attosecond pulses with a tunable ellipticity.

  16. Lie-optics, geometrical phase and nonlinear dynamics of self ...

    Indian Academy of Sciences (India)

    where the coefficients εo2 are determined by Taylor expansion as in eq. (1). It continues to be a popular theory even today [17] ... The message was very clear. The laser beam propagates in an appropriate ... the beam is to be determined from the beam evolution equation. We present here a very simple derivation of such a ...

  17. Study of static and dynamic stability of flexible rods in a geometrically nonlinear statement (United States)

    Annin, B. D.; Vlasov, A. Yu.; Zakharov, Yu. V.; Okhotkin, K. G.


    We study static and dynamic stability problems for a thin flexible rod subjected to axial compression with the geometric nonlinearity explicitly taken into account. In the case of static action of a force, the critical load and the bending shapes of the rod were determined by Euler. Lavrent'ev and Ishlinsky discovered that, in the case of rod dynamic loading significantly greater than the Euler static critical load, there arise buckling modes with a large number of waves in the longitudinal direction. Lavrent'ev and Ishlinsky referred to the first loading threshold discovered by Euler as the static threshold, and the subsequent ones were called dynamic thresholds; they can be attained under impact loading if the pulse growth time is less than the system relaxation time. Later, the buckling mechanism in this case and the arising parametric resonance were studied in detail by Academician Morozov and his colleagues. In this paper, we complete and develop the approach to studying dynamic rod systems suggested by Morozov; in particular, we construct exact and approximate analytic solutions by using a system of special functions generalizing the Jacobi elliptic functions. We obtain approximate analytic solutions of the nonlinear dynamic problem of flexible rod deformation under longitudinal loading with regard to the boundary conditions and show that the analytic solution of static rod system stability problems in a geometrically nonlinear statement permits exactly determining all possible shapes of the bent rod and the complete system of buckling thresholds. The study of approximate analytic solutions of dynamic problems of nonlinear vibrations of rod systems loaded by lumped forces after buckling in the deformed state allows one to determine the vibration frequencies and then the parametric resonance thresholds.

  18. Geometric nonlinear effects on the planar dynamics of a pivoted flexible beam encountering a point-surface impact

    International Nuclear Information System (INIS)

    Li Qing; Wang Tianshu; Ma Xingrui


    Flexible-body modeling with geometric nonlinearities remains a hot topic of research by applications in multibody system dynamics undergoing large overall motions. However, the geometric nonlinear effects on the impact dynamics of flexible multibody systems have attracted significantly less attention. In this paper, a point-surface impact problem between a rigid ball and a pivoted flexible beam is investigated. The Hertzian contact law is used to describe the impact process, and the dynamic equations are formulated in the floating frame of reference using the assumed mode method. The two important geometric nonlinear effects of the flexible beam are taken into account, i.e., the longitudinal foreshortening effect due to the transverse deformation, and the stress stiffness effect due to the axial force. The simulation results show that good consistency can be obtained with the nonlinear finite element program ABAQUS/Explicit if proper geometric nonlinearities are included in the floating frame formulation. Specifically, only the foreshortening effect should be considered in a pure transverse impact for efficiency, while the stress stiffness effect should be further considered in an oblique case with much more computational effort. It also implies that the geometric nonlinear effects should be considered properly in the impact dynamic analysis of more general flexible multibody systems

  19. Static aeroelastic analysis including geometric nonlinearities based on reduced order model

    Directory of Open Access Journals (Sweden)

    Changchuan Xie


    Full Text Available This paper describes a method proposed for modeling large deflection of aircraft in nonlinear aeroelastic analysis by developing reduced order model (ROM. The method is applied for solving the static aeroelastic and static aeroelastic trim problems of flexible aircraft containing geometric nonlinearities; meanwhile, the non-planar effects of aerodynamics and follower force effect have been considered. ROMs are computational inexpensive mathematical representations compared to traditional nonlinear finite element method (FEM especially in aeroelastic solutions. The approach for structure modeling presented here is on the basis of combined modal/finite element (MFE method that characterizes the stiffness nonlinearities and we apply that structure modeling method as ROM to aeroelastic analysis. Moreover, the non-planar aerodynamic force is computed by the non-planar vortex lattice method (VLM. Structure and aerodynamics can be coupled with the surface spline method. The results show that both of the static aeroelastic analysis and trim analysis of aircraft based on structure ROM can achieve a good agreement compared to analysis based on the FEM and experimental result.

  20. Optical bistability in nonlinear composites with coated ellipsoidal nanoparticles

    CERN Document Server

    Pinchuk, A


    Nonlinear composite structures show great promise for use in optical switching, signal processing, etc. We derive an effective nonlinear dielectric permittivity of composite structures where coated ellipsoidal nonlinear particles are imbedded in a linear host medium. The derived expression for the effective dielectric permittivity tensor follows the Clasius-Mossotti approximation. We observe conditions for the existence of the optical bistability effect in a coated ellipsoidal particle with a nonlinear core and a metallic shell. Our numerical results show stronger bistability effects in more dense suspensions of nonlinear heterogeneous ellipsoids.

  1. Gauge covariances and nonlinear optical responses (United States)

    Ventura, G. B.; Passos, D. J.; Lopes dos Santos, J. M. B.; Viana Parente Lopes, J. M.; Peres, N. M. R.


    The formalism of the reduced density matrix is pursued in both length and velocity gauges of the perturbation to the crystal Hamiltonian. The covariant derivative is introduced as a convenient representation of the position operator. This allow us to write compact expressions for the reduced density matrix in any order of the perturbation which simplifies the calculations of nonlinear optical responses; as an example, we compute the first- and third-order contributions of the monolayer graphene. Expressions obtained in both gauges share the same formal structure, allowing a comparison of the effects of truncation to a finite set of bands. This truncation breaks the equivalence between the two approaches: its proper implementation can be done directly in the expressions derived in the length gauge, but requires a revision of the equations of motion of the reduced density matrix in the velocity gauge.

  2. A Photonic Basis for Deriving Nonlinear Optical Response (United States)

    Andrews, David L.; Bradshaw, David S.


    Nonlinear optics is generally first presented as an extension of conventional optics. Typically the subject is introduced with reference to a classical oscillatory electric polarization, accommodating correction terms that become significant at high intensities. The material parameters that quantify the extent of the nonlinear response are cast as…

  3. Picosecond nonlinear optical properties of cuprous oxide with ...

    Indian Academy of Sciences (India)


    Feb 8, 2014 ... various important applications in the field of material research. In brief, nanotechnology is one of the most active research areas which find useful applications in different fields of science. Intense research is also pursued to develop new nonlinear optical materials with high optical nonlinearities and fast ...

  4. Nonlinear and quantum optics with liquid crystals

    International Nuclear Information System (INIS)

    Lukishova, Svetlana G


    Thermotropic liquid crystals' usual application is display technology. This paper describes experiments on light interaction with pure and doped liquid crystals under for these materials unconventional incident light powers: (1) under high-power laser irradiation, and (2) at the single-photon level. In (1), I will outline several nonlinear optical effects under high-power, nanosecond laser irradiation which should be taken into account in the design of lasers with liquid crystal components and in fabrication of optical power limiters based on liquid crystals: (1.1) athermal helical pitch dilation and unwinding of cholesteric mirrors (both in free space and inside laser resonators); (1.2) some pitfalls in measurements of refractive nonlinearity using z-scan technique under two-photon or linear absorption of liquids; (1.3) the first observation of thermal lens effects in liquid crystals under several-nanosecond, low-pulse-repetition rate (2-10 Hz) laser irradiation in the presence of two-photon absorption; (1.4) feedback-free kaleidoscope of patterns (hexagons, stripes, etc.) in dye-doped liquid crystals. In (2), at the single-photon level, it will be shown that with a proper selection of liquid crystals and a single-emitter dopant spectral range, liquid crystal structures can be used to control emitted single photons (both polarization and count rate). The application of the latter research is absolutely secure quantum communication with polarization coding of information. In particular, in (2.1), definite handedness, circular polarized cholesteric microcavity resonance in quantum dot fluorescence is reported. In (2.2), definite linear polarization of single (antibunched) photons from single-dye-molecules in planar-aligned nematic host is discussed. In (2.3), some results on photon antibunching from NV-color center in nanodiamond in liquid crystal host and circularly polarized fluorescence of definite handedness from nanocrystals doped with trivalent ions of

  5. Composition Feature of the Element Tangent Stiffness Matrix of Geometrically Nonlinear 2D Frame Structures

    Directory of Open Access Journals (Sweden)

    Romanas Karkauskas


    Full Text Available The expressions of the finite element method tangent stiffness matrix of geometrically nonlinear constructions are not fully presented in publications. The matrixes of small displacements stiffness are usually presented only. To solve various problems of construction analysis or design and to specify the mode of the real deflection of construction, it is necessary to have a fully described tangent matrix analytical expression. This paper presents a technique of tangent stiffness matrix generation using discrete body total potential energy stationary conditions considering geometrically nonlinear 2D frame element taking account of interelement interaction forces only. The obtained vector-function derivative of internal forces considering nodal displacements is the tangent stiffness matrix. The analytical expressions having nodal displacements of matrixes forming the content of the 2D frame construction element tangent stiffness matrix are presented in the article. The suggested methodology has been checked making symbolical calculations in the medium of MatLAB calculation complex. The analytical expression of the stiffness matrix has been obtained.Article in Lithuanian

  6. Numerical simulation of the geometrical-optics reduction of CE2 and comparisons to quasilinear dynamics (United States)

    Parker, Jeffrey B.


    Zonal flows have been observed to appear spontaneously from turbulence in a number of physical settings. A complete theory for their behavior is still lacking. Recently, a number of studies have investigated the dynamics of zonal flows using quasilinear (QL) theories and the statistical framework of a second-order cumulant expansion (CE2). A geometrical-optics (GO) reduction of CE2, derived under an assumption of separation of scales between the fluctuations and the zonal flow, is studied here numerically. The reduced model, CE2-GO, has a similar phase-space mathematical structure to the traditional wave-kinetic equation, but that wave-kinetic equation has been shown to fail to preserve enstrophy conservation and to exhibit an ultraviolet catastrophe. CE2-GO, in contrast, preserves nonlinear conservation of both energy and enstrophy. We show here how to retain these conservation properties in a pseudospectral simulation of CE2-GO. We then present nonlinear simulations of CE2-GO and compare with direct simulations of quasilinear (QL) dynamics. We find that CE2-GO retains some similarities to QL. The partitioning of energy that resides in the zonal flow is in good quantitative agreement between CE2-GO and QL. On the other hand, the length scale of the zonal flow does not follow the same qualitative trend in the two models. Overall, these simulations indicate that CE2-GO provides a simpler and more tractable statistical paradigm than CE2, but CE2-GO is missing important physics.

  7. Depth-of-field effects in wiggler radiation sources: Geometrical versus wave optics

    Directory of Open Access Journals (Sweden)

    Richard P. Walker


    Full Text Available A detailed analysis is carried out of the optical properties of synchrotron radiation emitted by multipole wigglers, concentrating on the effective source size and brightness and the so-called “depth of field” effects, concerning which there has been some controversy in the literature. By comparing calculations made with both geometrical optics and wave optics methods we demonstrate that the two approaches are not at variance, and that the wave optics results tend towards those of geometrical optics under well-defined conditions.

  8. Nonlinear super-resolution nano-optics and applications

    CERN Document Server

    Wei, Jingsong


    This book covers many advances in the subjects of nano-optics and nano photonics. The author describes the principle and technical schematics of common methods for breaking through the optical diffraction limit and focuses on realizing optical super-resolution with nonlinear effects of thin film materials. The applications of nonlinear optical super-resolution effects in nano-data storage, nanolithography, and nano-imaging are also presented. This book is useful to graduate students majoring in optics and nano science and also serves as a reference book for academic researchers, engineers, technical professionals in the fields of super-resolution optics and laser techniques, nano-optics and nano photonics, nano-data storage, nano imaging, micro/nanofabrication and nanolithography and nonlinear optics.

  9. Optical and Nonlinear Optical Response of Light Sensor Thin Films

    Directory of Open Access Journals (Sweden)

    S. Z. Weisz


    Full Text Available For potential ultrafast optical sensor application, both VO2 thin films andnanocomposite crystal-Si enriched SiO2 thin films grown on fused quartz substrates weresuccessfully prepared using pulsed laser deposition (PLD and RF co-sputteringtechniques. In photoluminescence (PL measurement c-Si/SiO2 film containsnanoparticles of crystal Si exhibits strong red emission with the band maximum rangingfrom 580 to 750 nm. With ultrashort pulsed laser excitation all films show extremelyintense and ultrafast nonlinear optical (NLO response. The recorded holography fromall these thin films in a degenerate-four-wave-mixing configuration shows extremelylarge third-order response. For VO2 thin films, an optically induced semiconductor-tometalphase transition (PT immediately occurred upon laser excitation. it accompanied.It turns out that the fast excited state dynamics was responsible to the induced PT. For c-Si/SiO2 film, its NLO response comes from the contribution of charge carriers created bylaser excitation in conduction band of the c-Si nanoparticles. It was verified byintroducing Eu3+ which is often used as a probe sensing the environment variations. Itturns out that the entire excited state dynamical process associated with the creation,movement and trapping of the charge carriers has a characteristic 500 ps duration.

  10. Topology optimization of nonlinear optical devices

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard


    This paper considers the design of nonlinear photonic devices. The nonlinearity stems from a nonlinear material model with a permittivity that depends on the local time-averaged intensity of the electric field. A finite element model is developed for time-harmonic wave propagation and an incremen......This paper considers the design of nonlinear photonic devices. The nonlinearity stems from a nonlinear material model with a permittivity that depends on the local time-averaged intensity of the electric field. A finite element model is developed for time-harmonic wave propagation...

  11. A New (?) Physiological Effect in a Demonstration Experiment in Geometrical Optics (United States)

    Ganci, S.


    A surprising phenomenology from a traditional demonstration experiment in Geometrical Optics reveals here an interesting matter of discussion and analysis. Hence, the main focus of this paper is to observe and discuss such an innovative phenomenology.

  12. A new (?) physiological effect in a demonstration experiment in geometrical optics (United States)

    Ganci, S.


    A surprising phenomenology from a traditional demonstration experiment in Geometrical Optics reveals here an interesting matter of discussion and analysis. Hence, the main focus of this paper is to observe and discuss such an innovative phenomenology.

  13. Nonlinear analysis of magnetospheric data Part I. Geometric characteristics of the AE index time series and comparison with nonlinear surrogate data

    Directory of Open Access Journals (Sweden)

    G. P. Pavlos


    Full Text Available A long AE index time series is used as a crucial magnetospheric quantity in order to study the underlying dynainics. For this purpose we utilize methods of nonlinear and chaotic analysis of time series. Two basic components of this analysis are the reconstruction of the experimental tiine series state space trajectory of the underlying process and the statistical testing of an null hypothesis. The null hypothesis against which the experimental time series are tested is that the observed AE index signal is generated by a linear stochastic signal possibly perturbed by a static nonlinear distortion. As dis ' ' ating statistics we use geometrical characteristics of the reconstructed state space (Part I, which is the work of this paper and dynamical characteristics (Part II, which is the work a separate paper, and "nonlinear" surrogate data, generated by two different techniques which can mimic the original (AE index signal. lie null hypothesis is tested for geometrical characteristics which are the dimension of the reconstructed trajectory and some new geometrical parameters introduced in this work for the efficient discrimination between the nonlinear stochastic surrogate data and the AE index. Finally, the estimated geometric characteristics of the magnetospheric AE index present new evidence about the nonlinear and low dimensional character of the underlying magnetospheric dynamics for the AE index.

  14. Microhardness studies on nonlinear optical L-alanine single crystals

    Indian Academy of Sciences (India)

    Keywords. Organic compounds; mechanical properties; hardness; anisotropy. 1. Introduction. Nonlinear optical applications find a variety of applica- tions such as frequency conversion, light modulation, opti- cal switching, optical memory storage and optical second harmonic generation (SHG) (Wang et al 1999; Chenthama ...

  15. Advances in chemical physics modern nonlinear optics, pt.1

    CERN Document Server

    Rice, Stuart A


    Partial table of contents: Hyper-Rayleigh and Hyper-Raman Rotational and Vibrational Spectroscopy (T. Bancewicz & Z. Ożgo). Polarization Properties of Hyper-Rayleigh and Hyper-Raman Scatterings (M. Kozierowski). Fast Molecular Reorientation in Liquid Crystals Probed by Nonlinear Optics (J. Lalanne, et al.). Nonlinear Propagation of Laser Light of Different Polarizations (G. Rivoire). Nonlinear Magneto-Optics of Magnetically Ordered Crystals (R. Zawodny). Dynamical Questions in Quantum Optics (A. Shumovsky). Quantum Resonance Fluorescence from Mutually Correlated Atoms (Z. Fi

  16. Optical nonlinearity of liquid nanosuspensions: Kerr versus exponential model (United States)

    Wright, E. M.; Lee, W. M.; Dholakia, K.; El-Ganainy, R.; Christodoulides, D. N.


    We report our experimental and theoretical progress towards elucidating the nonlinear optical response of nanosuspensions. To date, we have devised a fiber-optic variant of the Z-scan method to accurately measure the nonlinearity of liquid nanosuspensions. Furthermore, we shall show that the optical nonlinearity may be properly accounted theoretically by including both the virial coefficients for the soft-condensed matter system in addition to the exponential term, which does not account for particleparticle interactions, yielding an effective or renormalized Kerr effect in many cases.

  17. A qualitative analytical investigation of geometrically nonlinear effects in wind turbine blade cross sections

    DEFF Research Database (Denmark)

    Eder, Martin Alexander; Bitsche, Robert


    section, that was inspired by a wind turbine blade, it is demonstrated that geometric nonlinear effects can induce an in-plane opening deformation in re-entrant corners that may decrease the fatigue life. The opening effect induces Mode-I stress intensity factors which exceed the threshold for fatigue...... crack growth at loads well below the load-carrying capacity of the beam. The findings in this paper are twofold: Firstly, the investigated analysis procedure can be integrated into the design process of wind turbine blade cross sections. Secondly, the proposed approach serves as a basis...... for computationally efficient numerical analysis approaches of structures that comprise complex geometry and anisotropic material behaviour – such as wind turbine rotor blades....

  18. Nonlinear optical studies of curcumin metal derivatives with cw laser

    Energy Technology Data Exchange (ETDEWEB)

    Henari, F. Z., E-mail:; Cassidy, S. [Department of Basic Medical Sciences, Royal College of Surgeons in Ireland, Medical University of Bahrain (Bahrain)


    We report on measurements of the nonlinear refractive index and nonlinear absorption coefficients for curcumin and curcumin metal complexes of boron, copper, and iron at different wavelengths using the Z-scan technique. These materials are found to be novel nonlinear media. It was found that the addition of metals slightly influences its nonlinearity. These materials show a large negative nonlinear refractive index of the order of 10{sup −7} cm{sup 2}/W and negative nonlinear absorption of the order of 10{sup −6} cm/W. The origin of the nonlinearity was investigated by comparison of the formalism that is known as the Gaussian decomposition model with the thermal lens model. The optical limiting behavior based on the nonlinear refractive index was also investigated.

  19. Nonlinear optical studies of curcumin metal derivatives with cw laser

    International Nuclear Information System (INIS)

    Henari, F. Z.; Cassidy, S.


    We report on measurements of the nonlinear refractive index and nonlinear absorption coefficients for curcumin and curcumin metal complexes of boron, copper, and iron at different wavelengths using the Z-scan technique. These materials are found to be novel nonlinear media. It was found that the addition of metals slightly influences its nonlinearity. These materials show a large negative nonlinear refractive index of the order of 10 −7 cm 2 /W and negative nonlinear absorption of the order of 10 −6 cm/W. The origin of the nonlinearity was investigated by comparison of the formalism that is known as the Gaussian decomposition model with the thermal lens model. The optical limiting behavior based on the nonlinear refractive index was also investigated

  20. Nonlinear optical properties of ultrathin metal layers

    DEFF Research Database (Denmark)

    Lysenko, Oleg


    has the dominant contribution to the effective third-order nonlinear susceptibility of the longrange surface plasmon polariton mode in the strip plasmonic waveguides. The spectral broadening of the plasmonic mode in the waveguides is determined by the real part of the third-order nonlinear...... susceptibility of the gold layer, and the nonlinear power transmission of the plasmonic mode is determined by the imaginary part of the third-order nonlinear susceptibility of the gold layer. The experimental values of the third-order nonlinear susceptibility of gold for ultrathin layers are presented. The pulse...

  1. On the Geometrically Nonlinear Elastic Response of Class θ = 1 Tensegrity Prisms

    Directory of Open Access Journals (Sweden)

    Ida Mascolo


    Full Text Available The present work studies the geometrically nonlinear response of class θ = 1 tensegrity prisms modeled as a collection of elastic springs reacting in tension (strings or cables or compression (bars, under uniform uniaxial loading. The incremental equilibrium equations of the structure are numerically solved through a path-following procedure, with the aim of modeling the mechanical behavior of the structure in the large displacement regime. Several numerical results are presented with reference to a variety of physical models, which use two different materials for the cables and the bars, and show different aspect ratios associated with either “standard” or “expanded” configurations. An experimental validation of the predicted constitutive response is conducted with reference to a “thick” and a “slender” model, observing rather good theory vs. experiment matching. The given numerical and experimental results highlight that the elastic response of the examined structures may switch from stiffening to softening, depending on the geometry of the system, the magnitude of the external load, and the applied prestress. The outcomes of the current study confirm previous literature results on the elastic response of minimal tensegrity prisms, and pave the way to the use of tensegrity systems as nonlinear spring units forming tunable mechanical metamaterials.

  2. Geometrically and material non-linear analysis of bubble condenser steel structure

    International Nuclear Information System (INIS)

    Gyoergyi, J.; Lenkei, P.


    In frame of the project funded by the European Commission (EC) through the Phare and Tacis Programmes experimentally investigate the behaviour of the bubble condenser system (BCS) during phenomena induced by postulated design basis accidents (DBA). The bubble condenser steel structure consists of 12 trays. To enable the Bubble Condenser Test Prototype to be representative of the majority of trays and sections, it was decided to model a typical tray. The test results demonstrate the integrity of the standard tray pressure retaining boundary (side wall, face wall, ceiling and bottom) against a differential pressure (30 kPa). The stability of the side wall and the face wall of tray level 12 was not assured for this differential pressure. The thermal-hydraulic tests demonstrate that the maximum differential pressure across the tray walls in the case of Large Break Loss of Coolant Accident (LBLOCA) is 20 kPa. We have got from the experiences the differential pressure in function of time. The results of the approximate calculations showed the effect of nonlinearly. In case of calculation by FEM model we have done the elastic and linear analyses, and calculated with the geometrically and material non-linearity. (author)

  3. Squeezing in multi-mode nonlinear optical state truncation

    International Nuclear Information System (INIS)

    Said, R.S.; Wahiddin, M.R.B.; Umarov, B.A.


    In this Letter, we show that multi-mode qubit states produced via nonlinear optical state truncation driven by classical external pumpings exhibit squeezing condition. We restrict our discussions to the two- and three-mode cases

  4. Fast novel nonlinear optical NLC system with local response (United States)

    Iljin, Andrey; Residori, Stefania; Bortolozzo, Umberto


    Nonlinear optical performance of a novel liquid crystalline (LC) cell has been studied in two-wave mixing experiments revealing high diffraction efficiency within extremely wide intensity range, fast recording times and spatial resolution. Photo-induced modulation of the LC order parameter resulting from trans-cis isomerisation of dye molecules causes consequent changes of refractive indices of the medium (Light-Induced Order Modification, LIOM-mechanism) and is proved to be the main mechanism of optical nonlinearity. The proposed arrangement of the electric-field-stabilised homeotropic alignment hinders the LC director reorientation, prevents appearance of surface effects and ensures the optical cell quality. The LIOM-type nonlinearity, characterised with the substantially local nonlinear optical response, could also be extended for the recording of arbitrary phase profiles as requested in several applications for light-beam manipulation, recording of dynamic volume holograms and photonic lattices.

  5. Ultra-Fast Optical Signal Processing in Nonlinear Silicon Waveguides

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Galili, Michael; Pu, Minhao


    We describe recent demonstrations of exploiting highly nonlinear silicon nanowires for processing Tbit/s optical data signals. We perform demultiplexing and optical waveform sampling of 1.28 Tbit/s and wavelength conversion of 640 Gbit/s data signals.......We describe recent demonstrations of exploiting highly nonlinear silicon nanowires for processing Tbit/s optical data signals. We perform demultiplexing and optical waveform sampling of 1.28 Tbit/s and wavelength conversion of 640 Gbit/s data signals....

  6. Ripple distribution for nonlinear fiber-optic channels. (United States)

    Sorokina, Mariia; Sygletos, Stylianos; Turitsyn, Sergei


    We demonstrate data rates above the threshold imposed by nonlinearity on conventional optical signals by applying novel probability distribution, which we call ripple distribution, adapted to the properties of the fiber channel. Our results offer a new direction for signal coding, modulation and practical nonlinear distortions compensation algorithms.

  7. Enhancement of nonlinear optical properties of compounds of silica

    Indian Academy of Sciences (India)

    The aim of this paper is to introduce a method for enhancing the nonlinear optical properties in silica glass by using metallic nanoparticles. First, the T-matrix method is developed to calculate the effective dielectric constant for the compound of silica glass and metallic nanoparticles, both of which possess nonlinear dielectric ...

  8. Nonlinear Fourier transform for dual-polarization optical communication system

    DEFF Research Database (Denmark)

    Gaiarin, Simone

    communication is considered an emerging paradigm in fiber-optic communications that could potentially overcome these limitations. It relies on a mathematical technique called “inverse scattering transform” or “nonlinear Fourier transform (NFT)” to exploit the “hidden” linearity of the nonlinear Schrödinger...

  9. Cross-Grade Comparison of Students' Conceptual Understanding with Lenses in Geometric Optics (United States)

    Tural, G.


    Students commonly find the field of physics difficult. Therefore, they generally have learning problems. One of the subjects with which they have difficulties is optics within a physics discipline. This study aims to determine students' conceptual understanding levels at different education levels relating to lenses in geometric optics. A…

  10. Innovative education networking aimed at multimedia tools for geometrical optics learning (United States)

    García-Martínez, P.; Zapata-Rodríguez, C. J.; Ferreira, C.; Fernández, I.; Pastor, D.; Nasenpour, M.; Moreno, I.; Sánchez-López, M. M.; Espinosa, J.; Mas, D.; Miret, J. J.


    We present a purposeful initiative to open new grounds for teaching Geometrical Optics. It is based on the creation of an innovative education networking involving academic staff from three Spanish universities linked together around Optics. Nowadays, students demand online resources such as innovative multimedia tools for complementing the understanding of their studies. Geometrical Optics relies on basics of light phenomena like reflection and refraction and the use of simple optical elements such as mirrors, prisms, lenses, and fibers. The mathematical treatment is simple and the equations are not too complicated. But from our long time experience in teaching to undergraduate students, we realize that important concepts are missed by these students because they do not work ray tracing as they should do. Moreover, Geometrical Optics laboratory is crucial by providing many short Optics experiments and thus stimulating students interest in the study of such a topic. Multimedia applications help teachers to cover those student demands. In that sense, our educational networking shares and develops online materials based on 1) video-tutorials of laboratory experiences and of ray tracing exercises, 2) different online platforms for student self-examinations and 3) computer assisted geometrical optics exercises. That will result in interesting educational synergies and promote student autonomy for learning Optics.

  11. Shocks, singularities and oscillations in nonlinear optics and fluid mechanics

    CERN Document Server

    Santo, Daniele; Lannes, David


    The book collects the most relevant results from the INdAM Workshop "Shocks, Singularities and Oscillations in Nonlinear Optics and Fluid Mechanics" held in Rome, September 14-18, 2015. The contributions discuss recent major advances in the study of nonlinear hyperbolic systems, addressing general theoretical issues such as symmetrizability, singularities, low regularity or dispersive perturbations. It also investigates several physical phenomena where such systems are relevant, such as nonlinear optics, shock theory (stability, relaxation) and fluid mechanics (boundary layers, water waves, Euler equations, geophysical flows, etc.). It is a valuable resource for researchers in these fields. .

  12. Second-order nonlinear optical metamaterials: ABC-type nanolaminates

    International Nuclear Information System (INIS)

    Alloatti, L.; Kieninger, C.; Lauermann, M.; Köhnle, K.; Froelich, A.; Wegener, M.; Frenzel, T.; Freude, W.; Leuthold, J.; Koos, C.


    We demonstrate a concept for second-order nonlinear metamaterials that can be obtained from non-metallic centrosymmetric constituents with inherently low optical absorption. The concept is based on iterative atomic-layer deposition of three different materials, A = Al 2 O 3 , B = TiO 2 , and C = HfO 2 . The centrosymmetry of the resulting ABC stack is broken since the ABC and the inverted CBA sequences are not equivalent—a necessary condition for non-zero second-order nonlinearity. In our experiments, we find that the bulk second-order nonlinear susceptibility depends on the density of interfaces, leading to a nonlinear susceptibility of 0.26 pm/V at a wavelength of 800 nm. ABC-type nanolaminates can be deposited on virtually any substrate and offer a promising route towards engineering of second-order optical nonlinearities at both infrared and visible wavelengths

  13. Linear and non-linear optics of condensed matter

    International Nuclear Information System (INIS)

    McLean, T.P.


    Part I - Linear optics: 1. General introduction. 2. Frequency dependence of epsilon(ω, k vector). 3. Wave-vector dependence of epsilon(ω, k vector). 4. Tensor character of epsilon(ω, k vector). Part II - Non-linear optics: 5. Introduction. 6. A classical theory of non-linear response in one dimension. 7. The generalization to three dimensions. 8. General properties of the polarizability tensors. 9. The phase-matching condition. 10. Propagation in a non-linear dielectric. 11. Second harmonic generation. 12. Coupling of three waves. 13. Materials and their non-linearities. 14. Processes involving energy exchange with the medium. 15. Two-photon absorption. 16. Stimulated Raman effect. 17. Electro-optic effects. 18. Limitations of the approach presented here. (author)

  14. Minimizing radiation damage in nonlinear optical crystals (United States)

    Cooke, D. Wayne; Bennett, Bryan L.; Cockroft, Nigel J.


    Methods are disclosed for minimizing laser induced damage to nonlinear crystals, such as KTP crystals, involving various means for electrically grounding the crystals in order to diffuse electrical discharges within the crystals caused by the incident laser beam. In certain embodiments, electrically conductive material is deposited onto or into surfaces of the nonlinear crystals and the electrically conductive surfaces are connected to an electrical ground. To minimize electrical discharges on crystal surfaces that are not covered by the grounded electrically conductive material, a vacuum may be created around the nonlinear crystal.

  15. Computational studies of third-order nonlinear optical properties of ...

    Indian Academy of Sciences (India)

    Anuj Kumar


    Jun 20, 2017 ... S8 atoms, while the highest negative charge is located over N19 atoms of the pyridine ring. The atoms having the highest positive and negative charges suggest the reactive sites of the molecule [20]. 4. Conclusion. A theoretical investigations on nonlinear optical behaviour, electronic and optical properties ...

  16. Approximate quantum statistical properties of a nonlinear optical coupler

    Czech Academy of Sciences Publication Activity Database

    Mandal, S.; Peřina, Jan


    Roč. 328, - (2004), s. 144-156 ISSN 0375-9601 R&D Projects: GA MŠk LN00A015 Keywords : nonlinear optical couplers * photon bunching Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.454, year: 2004

  17. Synthesis and nonlinear optical characterization of new 1, 3, 4 ...

    Indian Academy of Sciences (India)

    ... H, N analyses. The open-aperture z-scan experiment was employed to measure the optical nonlinearity of the samples at 532 nm, using 5 ns laser pulses. The measurements indicate that compound 4a, which contains Bromine, behaves as an optical limiter at this wavelength, with potential applications in optoelectronics.

  18. Black phosphorus: broadband nonlinear optical absorption and application (United States)

    Li, Ying; He, Yanliang; Cai, Yao; Chen, Shuqing; Liu, Jun; Chen, Yu; Yuanjiang, Xiang


    Black phosphorus (BP), 2D layered material with layered dependent direct bandgap (0.3 eV (bulk), 2.0 eV (single layer)) that has gained renewed attention, has been demonstrated as an extremely appropriate optical material for broadband optical applications from infrared to mid-infrared wavebands. Herein, by coupling multi-layer BP films with microfiber, we fabricated a nonlinear optical device with long light-matter interaction distance and enhanced damage threshold. Through taking full advantage of its fine nonlinear optical absorption property, we obtained stable mode-locking (51 ps) and Q-switched mode-locking states in Yb-doped or Er-doped (403.7 fs) all-fiber lasers and the single-longitudinal-mode operation (53 kHz) in an Er-doped fiber laser with enhanced power tolerance, using the same nonlinear optical device. Our results showed that BP could be a favorable nonlinear optical material for developing BP-enabled wave-guiding photonic devices, and revealed new insight into BP for high optical power unexplored optical devices.

  19. Performance improvement for optimization of the non-linear geometric fitting problem in manufacturing metrology (United States)

    Moroni, Giovanni; Syam, Wahyudin P.; Petrò, Stefano


    Product quality is a main concern today in manufacturing; it drives competition between companies. To ensure high quality, a dimensional inspection to verify the geometric properties of a product must be carried out. High-speed non-contact scanners help with this task, by both speeding up acquisition speed and increasing accuracy through a more complete description of the surface. The algorithms for the management of the measurement data play a critical role in ensuring both the measurement accuracy and speed of the device. One of the most fundamental parts of the algorithm is the procedure for fitting the substitute geometry to a cloud of points. This article addresses this challenge. Three relevant geometries are selected as case studies: a non-linear least-squares fitting of a circle, sphere and cylinder. These geometries are chosen in consideration of their common use in practice; for example the sphere is often adopted as a reference artifact for performance verification of a coordinate measuring machine (CMM) and a cylinder is the most relevant geometry for a pin-hole relation as an assembly feature to construct a complete functioning product. In this article, an improvement of the initial point guess for the Levenberg-Marquardt (LM) algorithm by employing a chaos optimization (CO) method is proposed. This causes a performance improvement in the optimization of a non-linear function fitting the three geometries. The results show that, with this combination, a higher quality of fitting results a smaller norm of the residuals can be obtained while preserving the computational cost. Fitting an ‘incomplete-point-cloud’, which is a situation where the point cloud does not cover a complete feature e.g. from half of the total part surface, is also investigated. Finally, a case study of fitting a hemisphere is presented.

  20. Hofstadter butterflies in nonlinear Harper lattices, and their optical realizations

    Energy Technology Data Exchange (ETDEWEB)

    Manela, Ofer; Segev, Mordechai [Department of Physics and Solid State Institute, Technion, Haifa 32000 (Israel); Christodoulides, Demetrios N [College of Optics/CREOL, University of Central Florida, FL 32816-2700 (United States); Kip, Detlef, E-mail: [Department of Electrical Engineering, Helmut Schmidt University, 22043 Hamburg (Germany)


    The ubiquitous Hofstadter butterfly describes a variety of systems characterized by incommensurable periodicities, ranging from Bloch electrons in magnetic fields and the quantum Hall effect to cold atoms in optical lattices and more. Here, we introduce nonlinearity into the underlying (Harper) model and study the nonlinear spectra and the corresponding extended eigenmodes of nonlinear quasiperiodic systems. We show that the spectra of the nonlinear eigenmodes form deformed versions of the Hofstadter butterfly and demonstrate that the modes can be classified into two families: nonlinear modes that are a 'continuation' of the linear modes of the system and new nonlinear modes that have no counterparts in the linear spectrum. Finally, we propose an optical realization of the linear and nonlinear Harper models in transversely modulated waveguide arrays, where these Hofstadter butterflies can be observed. This work is relevant to a variety of other branches of physics beyond optics, such as disorder-induced localization in ultracold bosonic gases, localization transition processes in disordered lattices, and more.

  1. Third-order nonlinear optical response of indigo carmine under 633 nm excitation for nonlinear optical applications (United States)

    Pramodini, S.; Poornesh, P.


    We report thermally induced third-order nonlinearity and optical limiting behaviour of Indigo Carmine dye. z-Scan technique was used to determine the sign and magnitude of absorptive and refractive nonlinearities. Continuous wave (CW) He-Ne laser operating at 633 nm was used as source of excitation. In open aperture z-scan experiments, samples exhibited reverse saturable absorption (RSA) process. For closed aperture z-scan experiments, samples revealed self-defocusing property. The presence of donor and acceptor groups in the structure increases the conjugation length and in turn increases the optical nonlinearity. Induced self-diffraction rings pattern was recorded for the samples and it is attributed to refractive index change and thermal lensing. Also, optical limiting and clamping studies were carried out for various input power. Optical clamping of about ~1 mW was observed. This endorses that the dye under investigation is a positive candidate for opto-electronic and photonic applications.

  2. Optical computation based on nonlinear total reflectional optical ...

    Indian Academy of Sciences (India)

    All-optical parallel computation is the key technology in all-optical net [1]. It is also the essential part of the optical computer [2]. Optical computing was a hot research field in the 1980s. But this work was not progressed because of material limitations. [3]. It received attention again with its progression in the last decades.

  3. Nonlinear optical studies of single gold nanoparticles

    NARCIS (Netherlands)

    Dijk, Meindert Alexander van


    Gold nanoparticles are spherical clusters of gold atoms, with diameters typically between 1 and 100 nanometers. The applications of these particles are rather diverse, from optical labels for biological experiments to data carrier for optical data storage. The goal of my project was to develop new

  4. Neutron optical tests of nonlinear wave mechanics

    International Nuclear Information System (INIS)

    Gahler, R.; Klein, A.G.; Zeilinger, A.


    The free-space propagation of matter waves is analysed with a view to placing an upper limit on the strength of possible non-linear terms in the Schrodinger equation. Such additional terms of the form psiF(/psi/ 2 ) were introduced by Bialynicki-Birula and Mycielski in order to counteract the spreading of wave packets, thereby allowing solutions which behave macroscopically like classical particles. For the particularly interesting case of a logarithmic nonlinearity, of the form F=-b ln/psi/ 2 it is found that the free-space propagation of slow neutrons places a very stringent upper limit on the magnitude of b. Precise measurements of Fresnel diffraction with slow neutrons do not give any evidence for nonlinear effects and allows the deduction of an upper limit for b -15 eV about 3 orders of magnitude smaller than the lower bound proposed by the above authors, making such nonlinearities extremely unlikely in the real world

  5. Widely tunable picosecond optical parametric oscillator using highly nonlinear fiber. (United States)

    Zhou, Yue; Cheung, Kim K Y; Yang, Sigang; Chui, P C; Wong, Kenneth K Y


    We demonstrated a fully fiber-integrated widely tunable picosecond optical parametric oscillator based on highly nonlinear fiber. The ring cavity with a 50 m highly nonlinear fiber was synchronously pumped with a picosecond mode-locked fiber laser. The tuning range was from 1413 to 1543 nm and from 1573 to 1695 nm, which was as wide as 250 nm. A high-quality pulse was generated with a pulse width narrower than that of the pump.

  6. Unidirectional transmission in 1D nonlinear photonic crystal based on topological phase reversal by optical nonlinearity

    Directory of Open Access Journals (Sweden)

    Chong Li


    Full Text Available We propose a scheme of unidirectional transmission in a 1D nonlinear topological photonic crystal based on the topological edge state and three order optical nonlinearity. The 1D photonic crystals consists of a nonlinear photonic crystal L and a linear photonic crystal R. In the backward direction, light is totally reflected for the photons transmission prohibited by the bandgap. While in the forward direction, light interacts with the nonlinear photonic crystal L by optical Kerr effect, bringing a topological phase reversal and results the topological edge mode arising at the interface which could transmit photons through the bandgaps both of the photonic crystal L and R. When the signal power intensity larger than a moderate low threshold value of 10.0 MW/cm2, the transmission contrast ratio could remain at 30 steadily.

  7. High-speed signal processing using highly nonlinear optical fibres

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Oxenløwe, Leif Katsuo; Mulvad, Hans Christian Hansen


    We review recent progress in all-optical signal processing techniques making use of conventional silica-based highly nonlinear fibres. In particular, we focus on recent demonstrations of ultra-fast processing at 640 Gbit/s and above, as well as on signal processing of novel modulation formats...... relying on the phase of the optical field. Topics covered include all-optical switching of 640 Gbit/s and 1.28 Tbit/s serial data, wavelength conversion at 640 Gbit/s, optical amplitude regeneration of differential phase shift keying (DPSK) signals, as well as midspan spectral inversion for differential 8...

  8. Low-light-level nonlinear optics with slow light

    International Nuclear Information System (INIS)

    Braje, Danielle A.; Balic, Vlatko; Yin, G.Y.; Harris, S.E.


    Electromagnetically induced transparency in an optically thick, cold medium creates a unique system where pulse-propagation velocities may be orders of magnitude less than c and optical nonlinearities become exceedingly large. As a result, nonlinear processes may be efficient at low-light levels. Using an atomic system with three, independent channels, we demonstrate a quantum interference switch where a laser pulse with an energy per area of ∼23 photons per λ 2 /(2π) causes a 1/e absorption of a second pulse

  9. Linear and nonlinear Zeno effects in an optical coupler

    International Nuclear Information System (INIS)

    Abdullaev, F. Kh.; Konotop, V. V.; Shchesnovich, V. S.


    It is shown that, in a simple coupler where one of the waveguides is subject to controlled losses of the electric field, it is possible to observe an optical analog of the linear and nonlinear quantum Zeno effects. The phenomenon consists in a counterintuitive enhancement of transparency of the coupler with an increase of the dissipation and represents an optical analog of the quantum Zeno effect. Experimental realization of the phenomenon based on the use of chalcogenide glasses is proposed. The system allows for observation of the crossover between the linear and nonlinear Zeno effects, as well as the effective manipulation of light transmission through the coupler.

  10. Stability Analysis of a Rigid Body with Attached Geometrically Nonlinear Rod by the Energy-Momentum Method


    Posbergh, T. A.; Simo, J. C.; Marsden, J. E.


    This paper applies the energy-momentum method to the problem of nonlinear stability of relative equilibria of a rigid body with attached flexible appendage in a uniformly rotating state. The appendage is modeled as a geometrically exact rod which allows for finite bending, shearing and twist in three dimensions. Application of the energy-momentum method to this example depends crucially on a special choice of variables in terms of which the second variation block diagonalizes into blocks a...

  11. Optical Beams in Nonlocal Nonlinear Media

    DEFF Research Database (Denmark)

    Królikowski, W.; Bang, Ole; Wyller, J.


    We discuss propagation of optical beams in nonlocal Kerr-like media with the nonlocality of general form. We study the effect of nonlocality on modulational instability of the plane wave fronts, collapse of finite beams and formation of spatial solitons.......We discuss propagation of optical beams in nonlocal Kerr-like media with the nonlocality of general form. We study the effect of nonlocality on modulational instability of the plane wave fronts, collapse of finite beams and formation of spatial solitons....

  12. Picosecond optical nonlinearities in symmetrical and unsymmetrical ...

    Indian Academy of Sciences (India)

    It is evident that the saturable absorption (SA) behaviour changed to reverse sat- urable absorption (RSA) and the nonlinear coefficients were obtained using the equation α = α0I/[1 + (I/Is)]. The open-aperture scans were fitted by solving the propagation equation for homogeneous medium dI/dz = {−α0I/[1+(I/Is)]}−βI2.


    Directory of Open Access Journals (Sweden)

    Vladimir P. Agapov


    Full Text Available Abstract. Objectives Modern building codes prescribe the calculation of building structures taking into account the nonlinearity of deformation. To achieve this goal, the task is to develop a methodology for calculating prestressed reinforced concrete beams, taking into account physical and geometric nonlinearity. Methods The methodology is based on nonlinear calculation algorithms implemented and tested in the computation complex PRINS (a program for calculating engineering constructions for other types of construction. As a tool for solving this problem, the finite element method is used. Non-linear calculation of constructions is carried out by the PRINS computational complex using the stepwise iterative method. In this case, an equation is constructed and solved at the loading step, using modified Lagrangian coordinates. Results The basic formulas necessary for both the formation and the solution of a system of nonlinear algebraic equations by the stepwise iteration method are given, taking into account the loading, unloading and possible additional loading. A method for simulating prestressing is described by setting the temperature action on the reinforcement and stressing steel rod. Different approaches to accounting for physical and geometric nonlinearity of reinforced concrete beam rods are considered. A calculation example of a flat beam is given, in which the behaviour of the beam is analysed at various stages of its loading up to destruction. Conclusion A program is developed for the calculation of flat and spatially reinforced concrete beams taking into account the nonlinearity of deformation. The program is adapted to the computational complex PRINS and as part of this complex is available to a wide range of engineering, scientific and technical specialists. 

  14. Nonlinear light-matter interactions in engineered optical media (United States)

    Litchinitser, Natalia

    In this talk, we consider fundamental optical phenomena at the interface of nonlinear and singular optics in artificial media, including theoretical and experimental studies of linear and nonlinear light-matter interactions of vector and singular optical beams in metamaterials. We show that unique optical properties of metamaterials open unlimited prospects to ``engineer'' light itself. Thanks to their ability to manipulate both electric and magnetic field components, metamaterials open new degrees of freedom for tailoring complex polarization states and orbital angular momentum (OAM) of light. We will discuss several approaches to structured light manipulation on the nanoscale using metal-dielectric, all-dielectric and hyperbolic metamaterials. These new functionalities, including polarization and OAM conversion, beam magnification and de-magnification, and sub-wavelength imaging using novel non-resonant hyperlens are likely to enable a new generation of on-chip or all-fiber structured light applications. The emergence of metamaterials also has a strong potential to enable a plethora of novel nonlinear light-matter interactions and even new nonlinear materials. In particular, nonlinear focusing and defocusing effects are of paramount importance for manipulation of the minimum focusing spot size of structured light beams necessary for nanoscale trapping, manipulation, and fundamental spectroscopic studies. Colloidal suspensions offer as a promising platform for engineering polarizibilities and realization of large and tunable nonlinearities. We will present our recent studies of the phenomenon of spatial modulational instability leading to laser beam filamentation in an engineered soft-matter nonlinear medium. Finally, we introduce so-called virtual hyperbolic metamaterials formed by an array of plasma channels in air as a result of self-focusing of an intense laser pulse, and show that such structure can be used to manipulate microwave beams in a free space. This

  15. Vibration analysis for the in-plane motions of a semi-circular pipe conveying fluid considering the geometric nonlinearity

    International Nuclear Information System (INIS)

    Jung, Do Han; Chung, Jin Tai


    The vibration of a semi-circular pipe conveying fluid is studied when the pipe is clamed at both ends. To consider the geometric nonlinearity, this study adopts the Lagrange strain theory for large deformation and the extensible dynamics based on the Euler-Bernoulli beam theory for slenderness assumption. By using the Hamilton principle, the non-linear partial differential equations are derived for the in-plane motions of the pipe, considering the fluid inertia forces as a kind of non-conservative forces. The linear and non-linear terms in the governing equations are compared with those in the previous study, and some significant differences are discussed. To investigated the dynamic characteristics of the system, the discretized equations of motion are derived from the Galerkin method. The natural frequencies varying with the flow velocity are computed from the two cases, which one is the linear problem and the other is the linearized problem in the neighborhood of the equilibrium position. Finally, the time responses at various flow velocities are directly computed by using the generalized-α method. From these results, we should consider the geometric nonlinearity to analyze dynamics of a semi-circular pipe conveying fluid more precisely

  16. Transverse correlations in triphoton entanglement: Geometrical and physical optics

    International Nuclear Information System (INIS)

    Wen Jianming; Rubin, Morton H.; Shih Yanhua; Xu, P.


    The transverse correlation of triphoton entanglement generated within a single crystal is analyzed. Among many interesting features of the transverse correlation, they arise from the spectral function F of the triphoton state produced in the parametric processes. One consequence of transverse effects of entangled states is quantum imaging, which is theoretically studied in photon counting measurements. Klyshko's two-photon advanced-wave picture is found to be applicable to the multiphoton entanglement with some modifications. We found that in the two-photon coincidence counting measurement by using triphoton entanglement, although the Gaussian thin lens equation (GTLE) holds, the imaging shown in coincidences is obscure and has a poor quality. This is because of tracing the remaining transverse modes in the untouched beam. In the triphoton imaging experiments, two kinds of cases have been examined. For the case that only one object with one thin lens is placed in the system, we found that the GTLE holds as expected in the triphoton coincidences and the effective distance between the lens and imaging plane is the parallel combination of two distances between the lens and two detectors weighted by wavelengths, which behaves as the parallel combination of resistors in the electromagnetism theory. Only in this case, a point-point correspondence for forming an image is well-accomplished. However, when two objects or two lenses are inserted in the system, though the GTLEs are well-satisfied, in general a point-point correspondence for imaging cannot be established. Under certain conditions, two blurred images may be observed in the coincidence counts. We have also studied the ghost interference-diffraction experiments by using double slits as apertures in triphoton entanglement. It was found that when two double slits are used in two optical beams, the interference-diffraction patterns show unusual features compared with the two-photon case. This unusual behavior is a

  17. Physics education through computational tools: the case of geometrical and physical optics (United States)

    Rodríguez, Y.; Santana, A.; Mendoza, L. M.


    Recently, with the development of more powerful and accurate computational tools, the inclusion of new didactic materials in the classroom is known to have increased. However, the form in which these materials can be used to enhance the learning process is still under debate. Many different methodologies have been suggested for constructing new relevant curricular material and, among them, just-in-time teaching (JiTT) has arisen as an effective and successful way to improve the content of classes. In this paper, we will show the implemented pedagogic strategies for the courses of geometrical and optical physics for students of optometry. Thus, the use of the GeoGebra software for the geometrical optics class and the employment of new in-house software for the physical optics class created using the high-level programming language Python is shown with the corresponding activities developed for each of these applets.

  18. Nonlinear Optical Absorption and Refraction Study of Metallophthalocyanine Dyes. (United States)

    Wei, Tai-Huei

    Metallophthalocyanines and related conjugated ring molecules have attracted recent interest because, as confined, reduced-dimensionality (2D) delocalized electronic systems, large electronic nonlinearities are expected. This has led to interest in: (1) developing a fundamental understanding of the mechanisms which contribute to the nonlinear optical response, (2) obtaining well defined and accurate measurements of the refractive and absorptive contributions to the observed nonlinearities, and (3) identifying means of enhancing and maximizing the nonlinear susceptibilities. This dissertation deals with the characterization of the nonlinear absorption and refraction of two representative metallophthalocyanine dyes: chloro aluminum phthalocyanine dissolved in methanol, referred to as CAP, and a silicon naphthalocyanine derivative dissolved in toluene, referred to as SiNc. Using the Z -scan technique, the experiments are performed on both the picosecond and nanosecond timescales at a wavelength of 0.532 mum. The Z-scan technique separates nonlinear absorption and nonlinear refraction by measuring both the total transmittance and far field axial transmittance of a focused Gaussian beam as a function of the position (z) of the material relative to the beam waist. In the picosecond regime, Z-scan experiments using pulses of different widths indicate that both nonlinear absorption and refraction are fluence dependent. Therefore, we determine the dominant nonlinearities are excited state absorption (ESA) and excited state refraction (ESR). Through nanosecond Z-scan measurements, we see additional nonlinear absorption and nonlinear refraction. By power limiting measurements using single picosecond pulses and trains of picosecond pulses separated by 7 nanosecond, this additional nonlinear absorption is determined due to intersystem crossing to the triplet state with subsequent triplet state ESA. Therefore, a five state model is used to explain the nonlinear absorption. On the

  19. Geometrically nonlinear dynamic and static analysis of shallow spherical shell resting on two-parameters elastic foundations

    International Nuclear Information System (INIS)

    Civalek, Ö.


    In the present study nonlinear static and dynamic responses of shallow spherical shells resting on Winkler–Pasternak elastic foundations are carried out. The formulation of the shells is based on the Donnell theory. The nonlinear governing equations of motion of shallow shells are discretized in space and time domains using the discrete singular convolution and the differential quadrature methods, respectively. The validity of the present method is demonstrated by comparing the present results with those available in the open literature. The effects of the Winkler and Pasternak foundation parameters on nonlinear static and dynamic response of shells are investigated. Some results are also presented for circular plate as special case. Damping effect on nonlinear dynamic response of shells is studied. It is important to state that the increase in damping parameter causes decrease in the dynamic response of the shells. It is shown that the shear parameter of the foundation has a significant influence on the dynamic and static response of the shells. Also, the response of the shell is decreased with the increasing value of the shear parameter of the foundation. Parametric studies considering different geometric variables have also been investigated. -- Highlights: • Nonlinear responses of shallow spherical shells are presented. • The effects of foundation parameters are investigated. • Damping effect on nonlinear dynamic response of shells is also studied

  20. A topological investigation of the nonlinear optical compound: iodoform octasulfur. (United States)

    Wolstenholme, David J; Robertson, Katherine N; Gonzalez, Eduardo Mesa; Cameron, T Stanley


    The crystal structure of the nonlinear optical material, iodoform octasulfur (CHI3.(S8)3), in the polar space group R3m, has been shown to contain three unique S...I and several S...S close contacts (VSEPR theory.

  1. Optoelectronic and nonlinear optical processes in low dimensional ...

    Indian Academy of Sciences (India)

    optical response and high luminescence quantum yield expected in these systems is a consequence of huge en- hancement of transition probabilities ensuing ... compression and storage, can all be realized by nonlinear dynamical systems as these exhibit self .... or a very slow recovery. However, since the effect is com-.

  2. Electronic absorption spectra and nonlinear optical properties of CO ...

    Indian Academy of Sciences (India)

    We have investigated the structural aspects of several carbon dioxide molecular aggregates and their spectroscopic and nonlinear optical properties within the quantum chemical theory framework. We find that, although the single carbon dioxide molecule prefers to be in a linear geometry, the puckering of angles occur in ...

  3. An investigation on structural, vibrational and nonlinear optical ...

    Indian Academy of Sciences (India)

    Thermodynamical parameters along with the nonlinear optical (NLO) behavior of the title molecule are also discussed. The lower value of frontier orbital energy gap and a higher value of dipole moment suggest that the title compound is highly reactive. The NLO behavior of the title compound has been achieved by dipole ...

  4. Nonlinear optical studies in semiconductor-doped glasses under ...

    Indian Academy of Sciences (India)

    Abstract. Nonlinear optical studies in semiconductor-doped glasses (SDGs) are per- formed under femtosecond laser pulse excitation. Z-scan experiments with 800 nm wave- length pulses are used to excite SDG samples in the resonance and non-resonance regimes. Schott colour glass filter OG 515 shows stronger ...

  5. Optical activity via Kerr nonlinearity in a spinning chiral medium

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Anwar Ali, E-mail: [Department of Physics, University of Malakand at Chakdara Dir(L) (Pakistan); Bacha, Bakht Amin, E-mail: [Department of Physics, University of Malakand at Chakdara Dir(L) (Pakistan); Khan, Rahmat Ali, E-mail: [Department of Mathematics, University of Malakand (Pakistan)


    Optical activity is investigated in a chiral medium by employing the four level cascade atomic model, in which the optical responses of the atomic medium are studied with Kerr nonlinearity. Light entering into a chiral medium splits into circular birefringent beams. The angle of divergence between the circular birefringent beams and the polarization states of the two light beams is manipulated with Kerr nonlinearity. In the stationary chiral medium the angle of divergence between the circular birefringent beams is calculated to be 1.3 radian. Furthermore, circular birefringence is optically controlled in a spinning chiral medium, where the maximum rotary photon drag angle for left (right) circularly polarized beam is ±1.1 (±1.5) microradian. The change in the angle of divergence between circular birefringent beams by rotary photon drag is calculated to be 0.4 microradian. The numerical results may help to understand image designing, image coding, discovery of photonic crystals and optical sensing technology. - Highlights: • Coherent control of a circular birefringence in a chiral medium is studied. • Angle of divergence between birefringent beams is modified with Kerr nonlinearity. • Rotary photon drag is controlled for birefringent beams and enhanced with Kerr nonlinearity in a spinning medium. • Rotation of the angle of divergence is observed with mechanical rotation of the medium about an axis and modified with Kerr effect. • A change in the angle of divergence is calculated by about a microradian with rotary photon drag.

  6. Microhardness studies on nonlinear optical L-alanine single crystals

    Indian Academy of Sciences (India)

    Sci., Vol. 36, No. 3, June 2013, pp. 471–474. c Indian Academy of Sciences. Microhardness studies on nonlinear optical L-alanine single crystals. R HANUMANTHARAO† and S KALAINATHAN‡,∗ ... ter to the area of the impression left on the specimen. Both ... where P is the applied load in kg, d is in mm and Hv is in kg mm.

  7. Measurement of the nonlinear optical phase response of liquefying gallium


    Petropoulos, P.; Kim, H.S.; Richardson, D.J.; Zheludev, N.I.


    We report a direct measurement of the nonlinear optical phase response of gallium/silica interface close to the metal's melting point. A reversible phase modulation of ~0.15 radians and ~30% change in reflectivity was observed for 5mW of power at 1549nm.

  8. Dielectric and metallic nanosuspensions with tunable optical nonlinearities (United States)

    Fardad, Shima; Man, Weining; Zhang, Ze; Salandrino, Alessandro; Heinrich, Matthias; Chen, Zhigang; Christodoulides, Demetrios N.


    We provide a brief report on our recent work on dielectric and metallic colloidal nanosuspensions with negative polarizability where we observed robust propagation of self-trapped light over a long distance. Our results open up new opportunities in developing soft-matter systems with tunable optical nonlinearities.

  9. Nonlinear Optics Approaches Towards Subdiffraction Resolution in CARS Imaging

    NARCIS (Netherlands)

    Boller, Klaus J.; Beeker, W.P.; Cleff, C.; Kruse, K.; Lee, Christopher James; Gross, P.; Offerhaus, Herman L.; Fallnich, Carsten; Herek, Jennifer Lynn; Fornasiero, E.F.; Rizzoli, S.O.


    In theoretical investigations, we review several nonlinear optical approaches towards subdiffraction-limited resolution in label-free imaging via coherent anti-Stokes Raman scattering (CARS). Using a density matrix model and numerical integration, we investigate various level schemes and

  10. Generalized dispersive wave emission in nonlinear fiber optics. (United States)

    Webb, K E; Xu, Y Q; Erkintalo, M; Murdoch, S G


    We show that the emission of dispersive waves in nonlinear fiber optics is not limited to soliton-like pulses propagating in the anomalous dispersion regime. We demonstrate, both numerically and experimentally, that pulses propagating in the normal dispersion regime can excite resonant dispersive radiation across the zero-dispersion wavelength into the anomalous regime.

  11. Linear and nonlinear optical spectroscopy: Spectral, temporal and spatial resolution

    DEFF Research Database (Denmark)

    Hvam, Jørn Marcher


    Selected linear and nonlinear optical spectroscopies are being described with special emphasis on the possibility of obtaining simultaneous spectral, temporal and spatial resolution. The potential of various experimental techniques is being demonstrated by specific examples mostly taken from inve...... investigations of the electronic, and opto-electronic, properties of semiconductor nanostructures....

  12. Nonlinear optical studies in semiconductor-doped glasses under ...

    Indian Academy of Sciences (India)

    Eg is the band gap of the semiconductor and hω is the excitation photon energy. Very limited studies were conducted in resonance excitation region in SDGs with high-intensity femtosecond laser pulses. Z-scan is now recognized as a standard technique [7] to study nonlinear optical properties and is widely used because ...

  13. Picosecond nonlinear optical properties of cuprous oxide with ...

    Indian Academy of Sciences (India)


    Feb 8, 2014 ... physics pp. 321–325. Picosecond nonlinear optical properties of cuprous oxide with different nano-morphologies. P HARSHAVARDHAN REDDY, H SEKHAR and D NARAYANA RAO. ∗. Laser Laboratory, School of Physics, University of Hyderabad, Hyderabad 500 046, India. ∗. Corresponding author.

  14. A variational approach to nonlinear evolution equations in optics

    Indian Academy of Sciences (India)

    practical application of the approach is demonstrated by some illustrative examples in connection with the nonlinear ... and creative use of the variational approach to solve more or less complicated problems. No attempt towards a ...... Dispersion-management is an attractive way to increase the capacity of optical communi-.

  15. Extra phase noise from thermal fluctuations in nonlinear optical crystals

    DEFF Research Database (Denmark)

    César, J. E. S.; Coelho, A.S.; Cassemiro, K.N.


    We show theoretically and experimentally that scattered light by thermal phonons inside a second-order nonlinear crystal is the source of additional phase noise observed in optical parametric oscillators. This additional phase noise reduces the quantum correlations and has hitherto hindered the d...

  16. Optical measuring system for the geometrical parameters of Rockwell and Vickers diamond hardness indenters (United States)

    Zhang, Liqiong; Cui, Yuanyuan; Zhang, Feng


    Hardness testing is widely used for characterizing the mechanical properties of materials. However, the measured hardness values in hardness measurements are strongly influenced by the geometrical parameters of diamond hardness indenters. In the most severe case, the geometrical error of the diamond indenter, Rockwell hardness measurements in particular, leads to be about 50% hardness measurement uncertainty. It has been generally recognized for many years that the geometry of diamond indenters must be calibrated or verified before use to correct the hardness value for each indenter and improve the hardness measurement uncertainty. The contact-based calibration methods and the contactless based optical measuring methods are two typical ways to calibrate the geometrical form of an indenter at present. The contact-based calibration methods characterized by large measurement range of tens of mm with nanometer resolution, has a time-consuming measurement process, the contactless based optical measuring methods have become a general trend. In this work, an optical measuring system, which employs the combination of an interferometric microscope and a profile projection technique, is presented to measure and calibrate the geometrical parameters of Rockwell and Vickers diamond hardness indenters in National Institute of Metrology of China. Initial experiments demonstrated that the angle and axis angle measurement of indenter are achieved with accuracy of 0.1°, the straightness deviation of Rockwell indenters is less than 2μm, the radius measurement uncertainty of the tip of Rockwell indenters is better than 5μm.

  17. An experimentally validated model for geometrically nonlinear plucking-based frequency up-conversion in energy harvesting (United States)

    Kathpalia, B.; Tan, D.; Stern, I.; Erturk, A.


    It is well known that plucking-based frequency up-conversion can enhance the power output in piezoelectric energy harvesting by enabling cyclic free vibration at the fundamental bending mode of the harvester even for very low excitation frequencies. In this work, we present a geometrically nonlinear plucking-based framework for frequency up-conversion in piezoelectric energy harvesting under quasistatic excitations associated with low-frequency stimuli such as walking and similar rigid body motions. Axial shortening of the plectrum is essential to enable plucking excitation, which requires a nonlinear framework relating the plectrum parameters (e.g. overlap length between the plectrum and harvester) to the overall electrical power output. Von Kármán-type geometrically nonlinear deformation of the flexible plectrum cantilever is employed to relate the overlap length between the flexible (nonlinear) plectrum and the stiff (linear) harvester to the transverse quasistatic tip displacement of the plectrum, and thereby the tip load on the linear harvester in each plucking cycle. By combining the nonlinear plectrum mechanics and linear harvester dynamics with two-way electromechanical coupling, the electrical power output is obtained directly in terms of the overlap length. Experimental case studies and validations are presented for various overlap lengths and a set of electrical load resistance values. Further analysis results are reported regarding the combined effects of plectrum thickness and overlap length on the plucking force and harvested power output. The experimentally validated nonlinear plectrum-linear harvester framework proposed herein can be employed to design and optimize frequency up-conversion by properly choosing the plectrum parameters (geometry, material, overlap length, etc) as well as the harvester parameters.

  18. Implementation of Nonlinear Control Laws for an Optical Delay Line (United States)

    Hench, John J.; Lurie, Boris; Grogan, Robert; Johnson, Richard


    This paper discusses the implementation of a globally stable nonlinear controller algorithm for the Real-Time Interferometer Control System Testbed (RICST) brassboard optical delay line (ODL) developed for the Interferometry Technology Program at the Jet Propulsion Laboratory. The control methodology essentially employs loop shaping to implement linear control laws. while utilizing nonlinear elements as means of ameliorating the effects of actuator saturation in its coarse, main, and vernier stages. The linear controllers were implemented as high-order digital filters and were designed using Bode integral techniques to determine the loop shape. The nonlinear techniques encompass the areas of exact linearization, anti-windup control, nonlinear rate limiting and modal control. Details of the design procedure are given as well as data from the actual mechanism.

  19. Development of Organic Nonlinear Optical Materials (United States)


    using the electrooptic method. A series of substituted silicon and aluminum phthalocyanines was ; pepared in order to investigate their second and third...processing and optical computing. One clear advantage of working with P) polymer materials is that poling and the questions it raises about thermal stability...well-known in polymer photophysics [20]. This leads to the question of what the actual mechanism is for the excited state annihilation. The simplest

  20. Nanophotonic Devices in Silicon for Nonlinear Optics (United States)


    arm length imbalance . A balanced MZI could maximize the optical bandwidth and make the device athermal, however an unbalanced device makes it possible...that the capacitive loading itself could become a limitation; at 1 GHz, the absolute value of the impedance of the two Csl capacitors is around 44Ω, and...metal-oxide- semiconductor capacitor ," Nature, vol. 427, pp. 615-618, 2004. [2] L. Liao, A. Liu, D. Rubin, J. Basak, Y. Chetrit, H. Nguyen, R. Cohen, N

  1. Determination of optical constants and nonlinear optical coefficients ...

    Indian Academy of Sciences (India)

    The optical properties of Violet 1-doped polyvinyl alcohol (PVA) have been investigated using Wemble and Didomenico (WD) method. The optical constants such as refractive index , the dispersion energy , the oscillation energy 0, the lattice dielectric constant ∞, light frequency dielectric constant 0 and the ratio of ...

  2. Nonlinear Quantum Optical Springs and Their Nonclassical Properties

    International Nuclear Information System (INIS)

    Faghihi, M.J.; Tavassoly, M.K.


    The original idea of quantum optical spring arises from the requirement of quantization of the frequency of oscillations in the Hamiltonian of harmonic oscillator. This purpose is achieved by considering a spring whose constant (and so its frequency) depends on the quantum states of another system. Recently, it is realized that by the assumption of frequency modulation of ω to ω√1+μa † a the mentioned idea can be established. In the present paper, we generalize the approach of quantum optical spring with particular attention to the dependence of frequency to the intensity of radiation field that naturally observes in the nonlinear coherent states, from which we arrive at a physical system has been called by us as nonlinear quantum optical spring. Then, after the introduction of the generalized Hamiltonian of nonlinear quantum optical spring and it's solution, we will investigate the nonclassical properties of the obtained states. Specially, typical collapse and revival in the distribution functions and squeezing parameters, as particular quantum features, will be revealed. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  3. Nonlinear Silicon Photonic Signal Processing Devices for Future Optical Networks

    Directory of Open Access Journals (Sweden)

    Cosimo Lacava


    Full Text Available In this paper, we present a review on silicon-based nonlinear devices for all optical nonlinear processing of complex telecommunication signals. We discuss some recent developments achieved by our research group, through extensive collaborations with academic partners across Europe, on optical signal processing using silicon-germanium and amorphous silicon based waveguides as well as novel materials such as silicon rich silicon nitride and tantalum pentoxide. We review the performance of four wave mixing wavelength conversion applied on complex signals such as Differential Phase Shift Keying (DPSK, Quadrature Phase Shift Keying (QPSK, 16-Quadrature Amplitude Modulation (QAM and 64-QAM that dramatically enhance the telecom signal spectral efficiency, paving the way to next generation terabit all-optical networks.

  4. Slow light, induced dispersion, enhanced nonlinearity, and optical solitons in a resonator-array waveguide. (United States)

    E Heebner, John; Boyd, Robert W; Park, Q-Han


    We describe an optical transmission line that consists of an array of wavelength-scale optical disk resonators coupled to an optical waveguide. Such a structure leads to exotic optical characteristics, including ultraslow group velocities of propagation, enhanced optical nonlinearities, and large dispersion with a controllable magnitude and sign. This device supports soliton propagation, which can be described by a generalized nonlinear Schrodinger equation.

  5. Nonlinear optics of light induced structural transitions in confined gallium

    International Nuclear Information System (INIS)

    MacDonald, Kevin Francis


    An ultra-high-vacuum system has been constructed to facilitate atomic-beam deposition of gallium on cryogenically cooled substrates, including optical fibre tips. Alongside this, a fibre-optic pump-probe diagnostic system, based on semiconductor lasers, has been developed to perform in-situ measurements of the linear and transient nonlinear optical properties of gallium nanostructures, both during and after deposition. This unique combination of deposition and optical diagnostic techniques has provided a new means of studying the growth and optical characteristics of gallium nanostructures under highly controlled conditions. The linear and nonlinear optical properties of a new material structure, namely gallium/glass interfaces prepared by ultrafast pulsed laser deposition (UPLD), have been studied for the first time. The reflectivity characteristics of these high-quality interfaces were measured under varying conditions of temperature and light intensity at 810 nm: At temperatures several degrees below gallium's melting point T m , excitation intensities of just a few -2 were seen to induce reflectivity changes of more than 30%. Experiments performed with a nanosecond optical parametric oscillator have illustrated that UPLD gallium/silica interfaces show a nonlinear response to optical excitation in the 440-680 nm wavelength range: Fluences of less than 10 -2 were seen to induce reflectivity changes of up to 35%, even at temperatures 15 deg below T m . It has been found that low power (17 μW average) laser illumination of cryogenically cooled substrates during atomic-beam deposition of gallium leads to the formation of uniformly sized gallium nanoparticles. This phenomenon is believed to be the result of a non-thermal light-assisted particle self-assembly process. Gallium nanoparticles have been seen to show a strongly temperature-dependent nonlinear response to low intensity, infrared (1550 nm) optical excitation: 1 μs pulses with peak intensities

  6. Materials for Nonlinear Optics Chemical Perspectives (United States)


    Lind, R. C. J. Opt, Soc. Am., 1983, 73, 647. & EATON Nonfilk’ Optical Matrials 155 125 Borrelli , N. F.; Hall, D. W.; Holland, H. J.; Smith, D. W. J...1983, 73, 647. 128 Borrelli , N. F.; Hall, D. W.; Holland, H. J.; Smith, D. W. J. Appl. Phys., 1987, 61, 5399. 129 Olbright, 0. R.; Peyghambarian, N...Allenes and Cumulenes. A Laboratory Manual -, Elsevier. Amsterdam, 1981; p. 146. 41. See for example: Neenan, T.X; Whitesides, G.M. J. Og, Chem, 1989

  7. Second-order nonlinear optical metamaterials: ABC-type nanolaminates

    Energy Technology Data Exchange (ETDEWEB)

    Alloatti, L., E-mail:; Kieninger, C.; Lauermann, M.; Köhnle, K. [Institute of Photonics and Quantum Electronics (IPQ), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Froelich, A.; Wegener, M. [Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe (Germany); Frenzel, T. [Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Freude, W. [Institute of Photonics and Quantum Electronics (IPQ), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Institute for Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen (Germany); Leuthold, J.; Koos, C., E-mail: [Institute of Photonics and Quantum Electronics (IPQ), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Institute for Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen (Germany)


    We demonstrate a concept for second-order nonlinear metamaterials that can be obtained from non-metallic centrosymmetric constituents with inherently low optical absorption. The concept is based on iterative atomic-layer deposition of three different materials, A = Al{sub 2}O{sub 3}, B = TiO{sub 2}, and C = HfO{sub 2}. The centrosymmetry of the resulting ABC stack is broken since the ABC and the inverted CBA sequences are not equivalent—a necessary condition for non-zero second-order nonlinearity. In our experiments, we find that the bulk second-order nonlinear susceptibility depends on the density of interfaces, leading to a nonlinear susceptibility of 0.26 pm/V at a wavelength of 800 nm. ABC-type nanolaminates can be deposited on virtually any substrate and offer a promising route towards engineering of second-order optical nonlinearities at both infrared and visible wavelengths.

  8. Modified geometrical optics of a smoothly inhomogeneous isotropic medium: the anisotropy, Berry phase, and the optical Magnus effect. (United States)

    Bliokh, K Yu; Bliokh, Yu P


    We present a modification of the geometrical optics method, which allows one to properly separate the complex amplitude and the phase of the wave solution. Appling this modification to a smoothly inhomogeneous isotropic medium, we show that in the first geometrical optics approximation the medium is weakly anisotropic. The refractive index, being dependent on the direction of the wave vector, contains the correction, which is proportional to the Berry geometric phase. Two independent eigenmodes of right-hand and left-hand circular polarizations exist in the medium. Their group velocities and phase velocities differ. The difference in the group velocities results in the shift of the rays of different polarizations (the optical Magnus effect). The difference in the phase velocities causes an increase of the Berry phase along with the interference of two modes leading to the familiar Rytov law about the rotation of the polarization plane of a wave. The theory developed suggests that both the optical Magnus effect and the Berry phase are accompanying nonlocal topological effects. In this paper the Hamilton ray equations giving a unified description for both of these phenomena have been derived and also a novel splitting effect for a ray of noncircular polarization has been predicted. Specific examples are also discussed.

  9. Nonlinear Optical Parameters of Magnetoactive Semiconductor-Plasmas (United States)

    Singh, M.; Joseph, D.; Duhan, S.

    The nonlinear optical parameters (absorption coefficient and refractive index) of semiconductor-plasmas subjected to a transverse magnetic field have been investigated analytically. By employing the coupled-mode scheme, an expression of third-order optical susceptibility and resultant nonlinear absorption and refractive index of the medium are obtained. The analysis has been applied to both cases, viz., centrosymmetric (β = 0) and noncentrosymmetric (β ≠ 0) in the presence of magnetic field. The numerical estimates are made for InSb crystal at liquid nitrogen temperature duly irradiated by a 10-nanosecond pulsed 10.6 μm CO2 laser. The influence of doping concentration and magnetic field on both the nonlinear absorption and refractive index has been explored, and the results are found to be well in agreement with theory and experiment. Analysis further establishes that absorption coefficient and refractive index can be controlled with precision in semiconductors by the proper selection of doping concentration and an external magnetic field, and hence these media may be used for fabrication of fast cubic nonlinear optical devices under off-resonant transition regime.

  10. The behavior of the geometrical parameters of optical beam of optical passive components under the long time thermal load (United States)

    Perecar, Frantisek; Latal, Jan; Bednarek, Lukas; Hajek, Lukas; Hruby, David; Vasinek, Vladimir; Nedoma, Jan; Jaros, Jakub


    TThe paper discuss about aging of the passive optical couplers in their burdened high temperature. The article focuses on applied research and experimental development of resources for safety operation of optical networks in environment with higher temperature. It addresses issues of accelerated aging of optical fiber components in their burdened with high temperature. How does temperature influence on optical network elements? It is necessary to specify the changes in the optical coupler and find out why these changes occur. This article is devoted experimental measurement of the impact of temperature loading on the geometrical parameters of optical beam of SM optical FBT couplers. In the paper there are compared couplers of different manufacturers and same dividing ratios of output power 1:8. Optical passive component were continuously exposed to temperature 95°C for long time period. Measurements are focused on the parameters of geometry of optical beam. Graphical and mathematical detect changes in the dissemination of energy coupler after long lasting dose of temperature loading are useful to understand the phenomenon of accelerated aging elements of optical networks in environments with an higher temperature.

  11. Cross-Kerr nonlinearities in an optically dressed periodic medium

    Energy Technology Data Exchange (ETDEWEB)

    Slowik, K; Raczynski, A; Zaremba, J [Instytut Fizyki, Uniwersytet Mikolaja Kopernika, ulica Grudziadzka 5, 87-100 Torun (Poland); Zielinska-Kaniasty, S [Instytut Matematyki i Fizyki, Uniwersytet Technologiczno-Przyrodniczy, Aleja Prof. S Kaliskiego 7, 85-789 Bydgoszcz (Poland); Artoni, M [Department of Physics and Chemistry of Materials, CNR-INFM Sensor Lab, Brescia University and European Laboratory for Nonlinear Spectroscopy, Firenze (Italy); La Rocca, G C, E-mail: [Scuola Normale Superiore and CNISM, Pisa (Italy)


    Cross-Kerr nonlinearities are analyzed for two light beams propagating in an atomic medium in the tripod configuration, dressed by a strong standing-wave laser field that induces periodic optical properties. The reflection and transmission spectra as well as the phases of both the reflected and transmitted components of the two beams are analyzed theoretically with nonlinearities up to third order being taken into account. Ranges of parameters are sought in which the cross-Kerr effect can be used as the basis of the phase gate.

  12. Single-scattering properties of Platonic solids in geometrical-optics regime

    International Nuclear Information System (INIS)

    Zhang Zhibo; Yang Ping; Kattawar, George W.; Wiscombe, Warren J.


    We investigate the single-scattering properties of the Platonic solids with size parameters in the geometrical-optics regime at wavelengths 0.66 and 11 μm using the geometrical-optics method. The comparisons between the results for the Platonic solids and four types of spherical equivalence show that the equal-surface-area spherical equivalence has the smallest errors in terms of the extinction cross section at both wavelengths. At a wavelength of 0.66 μm, all the spherical equivalences substantially overestimate the asymmetry factors of the Platonic solids; and in the case of strong absorption, they underestimate the single-scattering albedo. The comparisons also show that the spherical equivalences cannot be used to describe the spatial distribution of scattered intensity associated with a prismatic polyhedron

  13. Ablation and optical third-order nonlinearities in Ag nanoparticles

    Directory of Open Access Journals (Sweden)

    Carlos Torres-Torres


    Full Text Available Carlos Torres-Torres1, Néstor Peréa-López2, Jorge Alejandro Reyes-Esqueda3, Luis Rodríguez-Fernández3, Alejandro Crespo-Sosa3, Juan Carlos Cheang-Wong3, Alicia Oliver31Section of Graduate Studies and Research, School of Mechanical and Electrical Engineering, National Polytechnic Institute, Zacatenco, Distrito Federal, Mexico; 2Laboratory for Nanoscience and Nanotechnology Research and Advanced Materials Department, IPICYT, Camino a la Presa San Jose, San Luis Potosi, Mexico; 3Instituto de Física, Universidad Nacional Autónoma de México, A.P. 20-364, México, D.F. 01000, MéxicoAbstract: The optical damage associated with high intensity laser excitation of silver nanoparticles (NPs was studied. In order to investigate the mechanisms of optical nonlinearity of a nanocomposite and their relation with its ablation threshold, a high-purity silica sample implanted with Ag ions was exposed to different nanosecond and picosecond laser irradiations. The magnitude and sign of picosecond refractive and absorptive nonlinearities were measured near and far from the surface plasmon resonance (SPR of the Ag NPs with a self-diffraction technique. Saturable optical absorption and electronic polarization related to self-focusing were identified. Linear absorption is the main process involved in nanosecond laser ablation, but nonlinearities are important for ultrashort picosecond pulses when the absorptive process become significantly dependent on the irradiance. We estimated that near the resonance, picosecond intraband transitions allow an expanded distribution of energy among the NPs, in comparison to the energy distribution resulting in a case of far from resonance, when the most important absorption takes place in silica. We measured important differences in the ablation threshold and we estimated that the high selectiveness of the SPR of Ag NPs as well as their corresponding optical nonlinearities can be strongly significant for laser

  14. Nonlinear Optics and Nonlinear Dynamics in Semiconductor Lasers Subject to External Optical Injection

    National Research Council Canada - National Science Library

    Simpson, Thomas


    ...) arrays, and analysis of chaotic dynamics that can be induced by optical injection. Under external optical injection, all semiconductor lasers tested, conventional edge emitting Fabry Perot laser diodes, VCSELs, and distributed feedback (DFB...

  15. Nonlinear optical polarization analysis in chemistry and biology

    CERN Document Server

    Simpson, Garth J


    This rigorous yet accessible guide presents a molecular-based description of nonlinear optical polarization analysis of chemical and biological assemblies. It includes discussion of the most common nonlinear optical microscopy and interfacial measurements used for quantitative analysis, specifically second harmonic generation (SHG), two-photon excited fluorescence (2PEF), vibrational sum frequency generation (SFG), and coherent anti-Stokes Raman spectroscopy/stimulated Raman spectroscopy (CARS/SRS). A linear algebra mathematical framework is developed, allowing step-wise systematic connections to be made between the observable measurements and the molecular response. Effects considered include local field corrections, the molecular orientation distribution, rotations between the molecular frame, the local frame and the laboratory frame, and simplifications from molecular and macromolecular symmetry. Specific examples are provided throughout the book, working from the common and relatively simple case studies ...

  16. Chromatic and Dispersive Effects in Nonlinear Integrable Optics

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Stephen D. [RadiaSoft, Boulder; Bruhwiler, David L. [RadiaSoft, Boulder; Valishev, Alexander [Fermilab; Nagaitsev, Sergei N. [Fermilab; Danilov, Viatcheslav V. [Oak Ridge


    Proton accumulator rings and other circular hadron accelerators are susceptible to intensity-driven parametric instabilities because the zero-current charged particle dynamics are characterized by a single tune. Landau damping can suppress these instabilities, which requires energy spread in the beam or introducing nonlinear magnets such as octupoles. However, this approach reduces dynamic aperture. Nonlinear integrable optics can suppress parametric instabilities independent of energy spread in the distribution, while preserving the dynamic aperture. This novel approach promises to reduce particle losses and enable order-of-magnitude increases in beam intensity. In this paper we present results, obtained using the Lie operator formalism, on how chromaticity and dispersion affect particle orbits in integrable optics. We conclude that chromaticity in general breaks the integrability, unless the vertical and horizontal chromaticities are equal. Because of this, the chromaticity correcting magnets can be weaker and fewer correcting magnet families are required, thus minimizing the impact on dynamic aperture.

  17. Dynamic nonlinear thermal optical effects in coupled ring resonators

    Directory of Open Access Journals (Sweden)

    Chenguang Huang


    Full Text Available We investigate the dynamic nonlinear thermal optical effects in a photonic system of two coupled ring resonators. A bus waveguide is used to couple light in and out of one of the coupled resonators. Based on the coupling from the bus to the resonator, the coupling between the resonators and the intrinsic loss of each individual resonator, the system transmission spectrum can be classified by three different categories: coupled-resonator-induced absorption, coupled-resonator-induced transparency and over coupled resonance splitting. Dynamic thermal optical effects due to linear absorption have been analyzed for each category as a function of the input power. The heat power in each resonator determines the thermal dynamics in this coupled resonator system. Multiple “shark fins” and power competition between resonators can be foreseen. Also, the nonlinear absorption induced thermal effects have been discussed.

  18. Nonlinear optical localization in embedded chalcogenide waveguide arrays

    International Nuclear Information System (INIS)

    Li, Mingshan; Huang, Sheng; Wang, Qingqing; Chen, Kevin P.; Petek, Hrvoje


    We report the nonlinear optical localization in an embedded waveguide array fabricated in chalcogenide glass. The array, which consists of seven waveguides with circularly symmetric cross sections, is realized by ultrafast laser writing. Light propagation in the chalcogenide waveguide array is studied with near infrared laser pulses centered at 1040 nm. The peak intensity required for nonlinear localization for the 1-cm long waveguide array was 35.1 GW/cm 2 , using 10-nJ pulses with 300-fs pulse width, which is 70 times lower than that reported in fused silica waveguide arrays and with over 7 times shorter interaction distance. Results reported in this paper demonstrated that ultrafast laser writing is a viable tool to produce 3D all-optical switching waveguide circuits in chalcogenide glass

  19. ZnS/PVA nanocomposites for nonlinear optical applications (United States)

    Ozga, K.; Michel, J.; Nechyporuk, B. D.; Ebothé, J.; Kityk, I. V.; Albassam, A. A.; El-Naggar, A. M.; Fedorchuk, A. O.


    We have found a correlation between ZnS nanocomposite nonlinear optical features and technological processing using electrolytic method. In the earlier researches this factor was neglected. However, it may open a new stage for operation by photovoltaic features of the well known semiconductors within a wide range of magnitudes. The titled nanostructured zinc sulfide (ZnS) was synthesized by electrolytic method. The obtained ZnS nano-crystallites possessed nano-particles sizes varying within 1.6 nm…1.8 nm. The titled samples were analyzed by XRD, HR-TEM, STEM, and nonlinear optical methods such as photo-induced two-photon absorption (TPA) and second harmonic generation (SHG). For this reason the nano-powders were embedded into the photopolymer poly(vinyl) alcohol (PVA) matrices. Role of aggregation in the mentioned properties is discussed. Possible origin of the such correlations are discussed.

  20. Growth and characterization of organic nonlinear optical material: Benzilic acid (United States)

    Baraniraj, T.; Philominathan, P.


    The organic nonlinear optical crystals of benzilic acid were grown by the slow evaporation method using ethanol as a solvent. Single-crystal X-ray diffraction (XRD), powder XRD studies and Fourier transform infrared (FTIR) spectral analysis were carried out to confirm the benzilic acid crystal. The optical transparency was studied by ultra violet (UV)-visible spectral analysis. Thermal properties of the grown crystals were studied by thermogravimetric and differential thermal analyses. The melting point of the grown crystal was confirmed by differential scanning calorimetry (DSC) analysis. The second harmonic generation (SHG) efficiency was found to be 2 times that of KDP.

  1. Femtosecond nonlinear fiber optics in the ionization regime. (United States)

    Hölzer, P; Chang, W; Travers, J C; Nazarkin, A; Nold, J; Joly, N Y; Saleh, M F; Biancalana, F; Russell, P St J


    By using a gas-filled kagome-style photonic crystal fiber, nonlinear fiber optics is studied in the regime of optically induced ionization. The fiber offers low anomalous dispersion over a broad bandwidth and low loss. Sequences of blueshifted pulses are emitted when 65 fs, few-microjoule pulses, corresponding to high-order solitons, are launched into the fiber and undergo self-compression. The experimental results are confirmed by numerical simulations which suggest that free-electron densities of ∼10(17) cm(-3) are achieved at peak intensities of 10(14) W/cm(2) over length scales of several centimeters.

  2. Reconstruction of temporal signals from nonlinear-optical measurements

    International Nuclear Information System (INIS)

    Kuznetsova, Tatiana I; Walmsley, I A


    A novel approach is proposed for reconstruction of the temporal characteristics of radiation from the results of nonlinear-optical measurements. A description is given of an algorithm for the processing of a two-dimensional set of data, based on inversion of the Gabor transform. This algorithm makes it possible to reconstruct arbitrary temporal signals, including multipulse signals, in the absence of any a priori information on their profile. (laser applications and other topics in quantum electronics)

  3. Linear and nonlinear optical properties of azobenzene derivatives. (United States)

    Krawczyk, P; Kaczmarek, A; Zaleśny, R; Matczyszyn, K; Bartkowiak, W; Ziółkowski, M; Cysewski, P


    The results of computations of spectroscopic parameters of lowest-lying electronic excited states of azobenezene derivatives are presented. The analysis of experimentally recorded spectra was supported by quantum chemical calculations using density functional theory. The theoretically determined resonant (two-photon absorption probabilities) and non-resonant (first-order hyperpolarisability) nonlinear optical properties are also discussed, with an eye towards the performance of recently proposed long-range corrected (LRC) schemes (LC-BLYP and CAM-B3LYP functionals).

  4. Structure, Electronic and Nonlinear Optical Properties of Furyloxazoles and Thienyloxazoles

    International Nuclear Information System (INIS)

    Dagli, Ozlem; Gok, Rabia; Bahat, Mehmet; Ozbay, Akif


    Geometry optimization, electronic and nonlinear optical properties of isomers of furyloxazole and thienyloxazole molecules are carried out at the B3LYP/6-311++G(2d,p) level. The conformational analysis of 12 compounds have been studied as a function of torsional angle between rings. Electronic and NLO properties such as dipole moment, energy gap, polarizability and first hyperpolarizability were also calculated. (paper)

  5. Optical tristability and ultrafast Fano switching in nonlinear magnetoplasmonic nanoparticles (United States)

    Yu, Wenjing; Ma, Pujuan; Sun, Hua; Gao, Lei; Noskov, Roman E.


    We consider light scattering by a coated magnetoplasmonic nanoparticle with a Kerr-type nonlinear plasmonic shell and a magneto-optic core. Such a structure features two plasmon dipole modes, associated with electronic oscillations on the inner and outer surfaces of the shell. Driven in a nonlinear regime, each mode exhibits a bistable response. Bistability of an inner plasmon leads to switching between this state and a Fano resonance (Fano switching). Once the external light intensity exceeds a critical value, the bistability zones of both eigenmodes overlap, yielding optical tristability characterized by three stable steady states for a given wavelength and light intensity. We develop a dynamic theory of transitions between nonlinear steady states and estimate the characteristic switching time to be as short as 0.5 ps. We also show that the magneto-optical effect allows red and blue spectral shifts of the Fano profile for right and left circular polarizations of the external light, rendering Fano switching sensitive to light polarization. Specifically, one can reach Fano switching for the right circular polarization while cancelling it for the left circular polarization. The results point to a class of ultrafast Fano switchers tunable by a magnetic field for applications in nanophotonics.

  6. Real-time correction by optical tracking with integrated geometric distortion correction for reducing motion artifacts in functional MRI. (United States)

    Rotenberg, David; Chiew, Mark; Ranieri, Shawn; Tam, Fred; Chopra, Rajiv; Graham, Simon J


    Head motion artifacts are a major problem in functional MRI that limit its use in neuroscience research and clinical settings. Real-time scan-plane correction by optical tracking has been shown to correct slice misalignment and nonlinear spin-history artifacts; however, residual artifacts due to dynamic magnetic field nonuniformity may remain in the data. A recently developed correction technique, Phase Labeling for Additional Coordinate Encoding, can correct for absolute geometric distortion using only the complex image data from two echo planar images with slightly shifted k-space trajectories. An approach is presented that integrates Phase Labeling for Additional Coordinate Encoding into a real-time scan-plane update system by optical tracking, applied to a tissue-equivalent phantom undergoing complex motion and an functional MRI finger tapping experiment with overt head motion to induce dynamic field nonuniformity. Experiments suggest that such integrated volume-by-volume corrections are very effective at artifact suppression, with potential to expand functional MRI applications. Copyright © 2012 Wiley Periodicals, Inc.

  7. Optimal Layout Design using the Element Connectivity Parameterization Method: Application to Three Dimensional Geometrical Nonlinear Structures

    DEFF Research Database (Denmark)

    Yoon, Gil Ho; Joung, Young Soo; Kim, Yoon Young


    The topology design optimization of “three-dimensional geometrically-nonlinear” continuum structures is still a difficult problem not only because of its problem size but also the occurrence of unstable continuum finite elements during the design optimization. To overcome this difficulty, the ele...

  8. Using geometric algebra to understand pattern rotations in multiple mirror optical systems

    International Nuclear Information System (INIS)

    Hanlon, J.; Ziock, H.


    Geometric Algebra (GA) is a new formulation of Clifford Algebra that includes vector analysis without notation changes. Most applications of Ga have been in theoretical physics, but GA is also a very good analysis tool for engineering. As an example, the authors use GA to study pattern rotation in optical systems with multiple mirror reflections. The common ways to analyze pattern rotations are to use rotation matrices or optical ray trace codes, but these are often inconvenient. The authors use GA to develop a simple expression for pattern rotation that is useful for designing or tolerancing pattern rotations in a multiple mirror optical system by inspection. Pattern rotation is used in many optical engineering systems, but it is not normally covered in optical system engineering texts. Pattern rotation is important in optical systems such as: (1) the 192 beam National ignition Facility (NIF), which uses square laser beams in close packed arrays to cut costs; (2) visual optical systems, which use pattern rotation to present the image to the observer in the appropriate orientation, and (3) the UR90 unstable ring resonator, which uses pattern rotation to fill a rectangular laser gain region and provide a filled-in laser output beam

  9. Spectrodirectional Investigation of a Geometric-Optical Canopy Reflectance Model by Laboratory Simulation (United States)

    Stanford, Adam Christopher

    Canopy reflectance models (CRMs) can accurately estimate vegetation canopy biophysical-structural information such as Leaf Area Index (LAI) inexpensively using satellite imagery. The strict physical basis which geometric-optical CRMs employ to mathematically link canopy bidirectional reflectance and structure allows for the tangible replication of a CRM's geometric abstraction of a canopy in the laboratory, enabling robust CRM validation studies. To this end, the ULGS-2 goniometer was used to obtain multiangle, hyperspectral (Spectrodirectional) measurements of a specially-designed tangible physical model forest, developed based upon the Geometric-Optical Mutual Shadowing (GOMS) CRM, at three different canopy cover densities. GOMS forward-modelled reflectance values had high levels of agreement with ULGS-2 measurements, with obtained reflectance RMSE values ranging from 0.03% to 0.1%. Canopy structure modelled via GOMS Multiple-Forward-Mode (MFM) inversion had varying levels of success. The methods developed in this thesis can potentially be extended to more complex CRMs through the implementation of 3D printing.

  10. Terahertz optical properties of nonlinear optical CdSe crystals (United States)

    Yan, Dexian; Xu, Degang; Li, Jining; Wang, Yuye; Liang, Fei; Wang, Jian; Yan, Chao; Liu, Hongxiang; Shi, Jia; Tang, Longhuang; He, Yixin; Zhong, Kai; Lin, Zheshuai; Zhang, Yingwu; Cheng, Hongjuan; Shi, Wei; Yao, Jianquan; Wu, Yicheng


    We investigate the optical properties of cadmium selenide (CdSe) crystals in a wide terahertz (THz) range from 0.2 to 6 THz by THz time-domain spectroscopy (THz-TDS) and Fourier transform infrared spectroscopy (FTIR). The refractive index, absorption coefficient and transmittance are measured and analyzed. The properties are characterized by several absorption peaks which represent the relevant phonon vibrations modes. The experimental results are in agreement with the theoretical results. The dispersion and absorption properties of CdSe crystal are analyzed in THz range. These properties indicate a good potential for THz sources and THz modulated devices.

  11. Developing and validating performance assessment tasks for concepts of geometrical optics (United States)

    Hossain, Karim

    This research study was designed to develop and validate an instrument based on performance-based tasks to assess senior high school and college students' laboratory skills in the area of geometrical optics. Data was obtained from eight high schools and five colleges from northwestern Pennsylvania and western New York. The total sample size for this study was 483 students; 195 college students, and 288 high school students. The research produced a series of six separate tasks in the specific areas of reflection and refraction. Each task utilized a separate set of materials that the students manipulated as a part of the task in order to demonstrate their understanding of the target inquiry skills in the area of geometrical optics. The reliability of the tasks (Coefficient Alpha) was high. Scores on the performance task determined by the researcher and separately by two physics professors were very highly correlated. The instrument was concluded to be reliable for use with sampled students. The content validity was ascertained by comparing each item of the task with the geometrical optics concepts by a panel of experts (two college professors and two high school teachers). The same panel also judged the scoring rubric for the instrument. The validity was also examined by eight research questions. These questions investigated whether selected variables, such as grade level, gender, level of physics courses and mathematics courses, instruction on optics, order of task, similarity of prior experience, and finally perceived importance of science had any significant relationships with the students' performance on the total tasks, individual tasks, and laboratory skills (performing and reasoning). Based on data collected with respect to these variables and statistical test that were performed, validity was supported for five out of eight of these research questions, with the exception of grade level, gender and mathematics. Several key areas for further investigations were

  12. Gallium nitride on gallium oxide substrate for integrated nonlinear optics

    KAUST Repository

    Awan, Kashif M.


    Gallium Nitride (GaN), being a direct bandgap semiconductor with a wide bandgap and high thermal stability, is attractive for optoelectronic and electronic applications. Furthermore, due to its high optical nonlinearity — the characteristic of all 111-V semiconductors — GaN is also expected to be a suitable candidate for integrated nonlinear photonic circuits for a plethora of apphcations, ranging from on-chip wavelength conversion to quantum computing. Although GaN devices are in commercial production, it still suffers from lack of a suitable substrate material to reduce structural defects like high densities of threading dislocations (TDs), stacking faults, and grain boundaries. These defects significandy deteriorate the optical quality of the epi-grown GaN layer, since they act as non-radiative recombination centers. Recent studies have shown that GaN grown on (−201) β-Gallium Oxide (Ga2O3) has superior optical quality due to a better lattice matching as compared to GaN grown on Sapphire (Al2O3) [1-3]. In this work, we report on the fabrication of GaN waveguides on GaiOj substrate and their optical characterization to assess their feasibihty for efficient four-wave mixing (FWM).

  13. Nonlinear optical properties of biomineral and biomimetical nanocomposite structures (United States)

    Kulchin, Yu. N.; Bezverbny, A. V.; Bukin, O. A.; Voznesensky, S. S.; Golik, S. S.; Mayor, A. Yu.; Shchipunov, Yu. A.; Nagorny, I. G.


    The transmission of laser femtosecond pulses by spicules of marine glass sponges and monolithic amorphous nanocomposite silica biomaterials synthesized on the basis of natural polysaccharides has been experimentally investigated. The strong non-linear optical properties of these biominerals have been revealed in spectral characteristics of transmitted ultra-short pulses (USP). Comparative analysis of the transmission spectra of USP reveals that spicules exhibit much stronger non-linear optical properties than quartz optical fibers. Recently new monolithic nanocomposite silica biomaterials were synthesized on the basis of various natural polysaccharides and completely water-soluble Si-precursor. The shape of transmitted spectrums through both spicules and new nanocomposite biomaterials demonstrates major changes indicating the broadening with formation markedly strong anti-Stokes component in the output spectrum with generation of supercontinuum spectra. The carried out studies have showed that the nature combination of spongin protein with silicon dioxide extracted from seawater by silicatein protein in glass sponge spicules and monolithic nanocomposite silica biomaterials are biological and biomimetical nanocomposite materials with unique optical properties.

  14. A geometrical approach to control and controllability of nonlinear dynamical networks. (United States)

    Wang, Le-Zhi; Su, Ri-Qi; Huang, Zi-Gang; Wang, Xiao; Wang, Wen-Xu; Grebogi, Celso; Lai, Ying-Cheng


    In spite of the recent interest and advances in linear controllability of complex networks, controlling nonlinear network dynamics remains an outstanding problem. Here we develop an experimentally feasible control framework for nonlinear dynamical networks that exhibit multistability. The control objective is to apply parameter perturbation to drive the system from one attractor to another, assuming that the former is undesired and the latter is desired. To make our framework practically meaningful, we consider restricted parameter perturbation by imposing two constraints: it must be experimentally realizable and applied only temporarily. We introduce the concept of attractor network, which allows us to formulate a quantifiable controllability framework for nonlinear dynamical networks: a network is more controllable if the attractor network is more strongly connected. We test our control framework using examples from various models of experimental gene regulatory networks and demonstrate the beneficial role of noise in facilitating control.

  15. Geometrical Nonlinear Aeroelastic Stability Analysis of a Composite High-Aspect-Ratio Wing

    Directory of Open Access Journals (Sweden)

    Chang Chuan Xie


    Full Text Available A composite high-aspect-ratio wing of a high-altitude long-endurance (HALE aircraft was modeled with FEM by MSC/NASTRAN, and the nonlinear static equilibrium state is calculated under design load with follower force effect, but without load redistribution. Assuming the little vibration amplitude of the wing around the static equilibrium state, the system is linearized and the natural frequencies and mode shapes of the deformed structure are obtained. Planar doublet lattice method is used to calculate unsteady aerodynamics in frequency domain ignoring the bending effect of the deflected wing. And then, the aeroelastic stability analysis of the system under a given load condition is successively carried out. Comparing with the linear results, the nonlinear displacement of the wing tip is higher. The results indicate that the critical nonlinear flutter is of the flap/chordwise bending type because of the chordwise bending having quite a large torsion component, with low critical speed and slowly growing damping, which dose not appear in the linear analysis. Furthermore, it is shown that the variation of the nonlinear flutter speed depends on the scale of the load and on the chordwise bending frequency. The research work indicates that, for the very flexible HALE aircraft, the nonlinear aeroelastic stability is very important, and should be considered in the design progress. Using present FEM software as the structure solver (e.g. MSC/NASTRAN, and the unsteady aerodynamic code, the nonlinear aeroelastic stability margin of a complex system other than a simple beam model can be determined.

  16. Nonlinear fiber-optic strain sensor based on four-wave mixing in microstructured optical fiber

    DEFF Research Database (Denmark)

    Gu, Bobo; Yuan, Scott Wu; Frosz, Michael H.


    We demonstrate a nonlinear fiber-optic strain sensor, which uses the shifts of four-wave mixing Stokes and anti-Stokes peaks caused by the strain-induced changes in the structure and refractive index of a microstructured optical fiber. The sensor thus uses the inherent nonlinearity of the fiber...... and does not require any advanced post-processing of the fiber. Strain sensitivity of -0.23 pm/mu epsilon is achieved experimentally and numerical simulations reveal that for the present fiber the sensitivity can be increased to -4.46 pm/mu epsilon by optimizing the pump wavelength and power....

  17. Nonlinear optical activity in Bridgman growth layered compounds

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M.I., E-mail: [Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)


    Layered semiconductor compound CdI{sub 2} has been grown with the Bridgman technique and studied by nonlinear transmittance spectroscopy. The optical absorption in CdI{sub 2} shows a nonlinear transmission of the incident laser power (P{sub 0}) within a lower power limit. The transmission, however, is found to saturate at high powers, giving a clamped output. The value of the incident power (P{sub 0C}) at which clamping starts is also found to depend on the crystal temperature (T{sub L}). The values of P{sub OC} ranges from 55 to 65 MW cm{sup -2} for T{sub L} = 4.2-180 K. The dynamic range (D{sub R}) as a function of T{sub L} is calculated and the values are found to range from D{sub R} = 2 to 1.6. The optical limiting mechanisms are discussed. The two-photon absorption (TPA) coefficient ({beta}) of the optical nonlinear process in CdI{sub 2} is estimated. The values are found to be within a range from {beta} = 47 to 25 cm GW{sup -1} and be decreasing with increasing T{sub L}. As expected for the TPA process, the experimental data within a certain range follows the linear relation: log (P{sub 0}/P{sub T}) = A{sub G} + {Omega}(P{sub 0} - P{sub T}), where P{sub T} is the transmitted power, A{sub G} is the absorbance of the ground state and {Omega} is a constant depending on the absorption cross-section and the relaxation time. The values of A{sub G} and {Omega} estimated from the fits to the measured data vary with T{sub L}. The findings resulting from this investigation might have potential applications in optical sensors protection.

  18. Geometric optics theory and design of astronomical optical systems using Mathematica

    CERN Document Server

    Romano, Antonio


    This text, now in its second edition, presents the mathematical background needed to design many optical combinations that are used in astronomical telescopes and cameras. It uses a novel approach to third-order aberration theory based on Fermat’s principle and the use of particular optical paths (called stigmatic paths) instead of rays, allowing for easier derivation of third-order formulae. Each optical combination analyzed is accompanied by a downloadable Mathematica® notebook that automates its third-order design, eliminating the need for lengthy calculations. The essential aspects of an optical system with an axis of rotational symmetry are introduced first, along with a development of Gaussian optics from Fermat’s principal. A simpler approach to third-order monochromatic aberrations based on both Fermat’s principle and stigmatic paths is then described, followed by a new chapter on fifth-order aberrations and their classification. Several specific optical devices are discussed and analyzed, incl...

  19. Simple and practical approach for computing the ray Hessian matrix in geometrical optics. (United States)

    Lin, Psang Dain


    A method is proposed for simplifying the computation of the ray Hessian matrix in geometrical optics by replacing the angular variables in the system variable vector with their equivalent cosine and sine functions. The variable vector of a boundary surface is similarly defined in such a way as to exclude any angular variables. It is shown that the proposed formulations reduce the computation time of the Hessian matrix by around 10 times compared to the previous method reported by the current group in Advanced Geometrical Optics (2016). Notably, the method proposed in this study involves only polynomial differentiation, i.e., trigonometric function calls are not required. As a consequence, the computation complexity is significantly reduced. Five illustrative examples are given. The first three examples show that the proposed method is applicable to the determination of the Hessian matrix for any pose matrix, irrespective of the order in which the rotation and translation motions are specified. The last two examples demonstrate the use of the proposed Hessian matrix in determining the axial and lateral chromatic aberrations of a typical optical system.

  20. ac electrokinetic micropumps: The effect of geometrical confinement, Faradaic current injection, and nonlinear surface capacitance

    DEFF Research Database (Denmark)

    Olesen, Laurits Højgaard; Bruus, Henrik; Ajdari, A.


    therefore extend the latter theories to account for three experimentally relevant effects: (i) vertical confinement of the pumping channel, (ii) Faradaic currents from electrochemical reactions at the electrodes, and (iii) nonlinear surface capacitance of the Debye layer. We report here that these effects...... indeed affect the pump performance in a way that we can rationalize by physical arguments....

  1. Symmetry, strain, defects, and the nonlinear optical response of crystalline BaTiO3/silicon (United States)

    Kormondy, Kristy; Abel, Stefan; Popoff, Youri; Sousa, Marilyne; Caimi, Daniele; Siegwart, Heinz; Marchiori, Chiara; Rossell, Marta; Demkov, Alex; Fompeyrine, Jean

    Recent progress has been made towards exploiting the linear electro-optic or Pockels effect in ferroelectric BaTiO3 (BTO) for novel integrated silicon photonics devices. In such structures, the crystalline symmetry and domain structure of BTO determine which electro-optic tensor elements are accessible under application of an external electric field. For epitaxial thin films of BTO on Si (001), the role of defects in strain relaxation can lead to very different crystalline symmetry even for films of identical thickness. Indeed, through geometric phase analysis of high-resolution scanning transmission electron microscopy images, we map changes of the in-plane and out-of-plane lattice parameters across two 80-nm-thick BTO films. A corresponding 20% difference in the effective electro-optic response was measured by analyzing induced rotation of the polarization of a laser beam (λ = 1550 nm) transmitted through lithographically defined electrodes. Understanding, controlling, and modelling the role of BTO symmetry in nonlinear optics is of fundamental importance for the development of a hybrid BTO/Si photonics platform.. Work supported by the NSF (IRES-1358111), AFOSR (FA9550-12-10494), and European Commission (FP7-ICT-2013-11-619456-SITOGA).

  2. Nonlinear optical properties of colloidal silver nanoparticles produced by laser ablation in liquids

    International Nuclear Information System (INIS)

    Karavanskii, V A; Krasovskii, V I; Ivanchenko, P V; Simakin, Aleksandr V


    The optical and nonlinear optical properties of colloidal solutions of silver obtained by laser ablation in water and ethanol are studied. It is shown that freshly prepared colloids experience a full or partial sedimentation by changing their nonlinear optical properties. Aqueous colloids undergo a partial sedimentation and their nonlinear optical absorption changes to nonlinear optical transmission. The obtained results are interpreted using the Drude model for metal particles taking the particle size into account and can be explained by the sedimentation of larger silver particles accompanied by the formation of a stable colloid containing silver nanoparticles with a tentatively silver oxide shell. The characteristic size of particles forming such a stable colloid is determined and its optical nonlinearity is estimated. (nonlinear optical phenomena)

  3. Non-linear optical titanyl arsenates: Crystal growth and properties (United States)

    Nordborg, Jenni Eva Louise

    Crystals are appreciated not only for their appearance, but also for their unique physical properties which are utilized by the photonic industry in appliances that we come across every day. An important part of enabling the technical use of optical devices is the manufacture of crystals. This dissertation deals with a specific group of materials called the potassium titanyl phosphate (KIP) family, known for their non-linear optical and ferroelectric properties. The isomorphs vary in their linear optical and dielectric properties, which can be tuned to optimize device performance by forming solid solutions of the different materials. Titanyl arsenates have a wide range of near-infrared transmission which makes them useful for tunable infrared lasers. The isomorphs examined in the present work were primarily RbTiOASO4 (RTA) and CsTiOAsO4 (CTA) together with the mixtures RbxCs 1-xTiOAsO4 (RCTA). Large-scale crystals were grown by top seeding solution growth utilizing a three-zone furnace with excellent temperature control. Sufficiently slow cooling and constant upward lifting produced crystals with large volumes useable for technical applications. Optical quality RTA crystals up to 10 x 12 x 20 mm were grown. The greater difficulty in obtaining good crystals of CTA led to the use of mixed RCTA materials. The mixing of rubidium and cesium in RCTA is more favorable to crystal growth than the single components in pure RTA and CTA. Mixed crystals are rubidium-enriched and contain only 20-30% of the cesium concentration in the flux. The cesium atoms show a preference for the larger cation site. The network structure is very little affected by the cation substitution; consequently, the non-linear optical properties of the Rb-rich isomorphic mixtures of RTA and CTA can be expected to remain intact. Crystallographic methods utilizing conventional X-ray tubes, synchrotron radiation and neutron diffraction have been employed to investigate the properties of the atomic

  4. Assessment of fibrotic liver disease with multimodal nonlinear optical microscopy (United States)

    Lu, Fake; Zheng, Wei; Tai, Dean C. S.; Lin, Jian; Yu, Hanry; Huang, Zhiwei


    Liver fibrosis is the excessive accumulation of extracellular matrix proteins such as collagens, which may result in cirrhosis, liver failure, and portal hypertension. In this study, we apply a multimodal nonlinear optical microscopy platform developed to investigate the fibrotic liver diseases in rat models established by performing bile duct ligation (BDL) surgery. The three nonlinear microscopy imaging modalities are implemented on the same sectioned tissues of diseased model sequentially: i.e., second harmonic generation (SHG) imaging quantifies the contents of the collagens, the two-photon excitation fluorescence (TPEF) imaging reveals the morphology of hepatic cells, while coherent anti-Stokes Raman scattering (CARS) imaging maps the distributions of fats or lipids quantitatively across the tissue. Our imaging results show that during the development of liver fibrosis (collagens) in BDL model, fatty liver disease also occurs. The aggregated concentrations of collagen and fat constituents in liver fibrosis model show a certain correlationship between each other.

  5. Higher-order modulation instability in nonlinear fiber optics. (United States)

    Erkintalo, Miro; Hammani, Kamal; Kibler, Bertrand; Finot, Christophe; Akhmediev, Nail; Dudley, John M; Genty, Goëry


    We report theoretical, numerical, and experimental studies of higher-order modulation instability in the focusing nonlinear Schrödinger equation. This higher-order instability arises from the nonlinear superposition of elementary instabilities, associated with initial single breather evolution followed by a regime of complex, yet deterministic, pulse splitting. We analytically describe the process using the Darboux transformation and compare with experiments in optical fiber. We show how a suitably low frequency modulation on a continuous wave field induces higher-order modulation instability splitting with the pulse characteristics at different phases of evolution related by a simple scaling relationship. We anticipate that similar processes are likely to be observed in many other systems including plasmas, Bose-Einstein condensates, and deep water waves. © 2011 American Physical Society

  6. Tunable orbital angular momentum mode filter based on optical geometric transformation. (United States)

    Huang, Hao; Ren, Yongxiong; Xie, Guodong; Yan, Yan; Yue, Yang; Ahmed, Nisar; Lavery, Martin P J; Padgett, Miles J; Dolinar, Sam; Tur, Moshe; Willner, Alan E


    We present a tunable mode filter for spatially multiplexed laser beams carrying orbital angular momentum (OAM). The filter comprises an optical geometric transformation-based OAM mode sorter and a spatial light modulator (SLM). The programmable SLM can selectively control the passing/blocking of each input OAM beam. We experimentally demonstrate tunable filtering of one or multiple OAM modes from four multiplexed input OAM modes with vortex charge of ℓ=-9, -4, +4, and +9. The measured output power suppression ratio of the propagated modes to the blocked modes exceeds 14.5 dB.

  7. Johann Joseph on Geometrical-Optical Illusions: A Translation and Commentary. (United States)

    Wade, Nicholas J; Todorović, Dejan; Phillips, David; Lingelbach, Bernd


    The term geometrical-optical illusions was coined by Johann Joseph Oppel (1815-1894) in 1855 in order to distinguish spatial distortions of size and orientation from the broader illusions of the senses. We present a translation of Oppel's article and a commentary on the material described in it. Oppel did much more than give a name to a class of visual spatial distortions. He examined a variety of figures and phenomena that were precursors of later, named illusions, and attempted to quantify and interpret them.

  8. Optical nonlinearity enhancement with graphene-decorated silicon waveguides (United States)

    Ishizawa, Atsushi; Kou, Rai; Goto, Takahiro; Tsuchizawa, Tai; Matsuda, Nobuyuki; Hitachi, Kenichi; Nishikawa, Tadashi; Yamada, Koji; Sogawa, Tetsuomi; Gotoh, Hideki


    Broadband on-chip optical frequency combs (OFCs) are important for expanding the functionality of photonic integrated circuits. Here, we demonstrate a huge local optical nonlinearity enhancement using graphene. A waveguide is decorated with graphene by precisely manipulating graphene’s area and position. Our approach simultaneously achieves both an extremely efficient supercontinuum and ultra-short pulse generation. With our graphene-decorated silicon waveguide (G-SWG), we have achieved enhanced spectral broadening of femtosecond pump pulses, along with an eightfold increase in the output optical intensity at a wavelength approximately 200 nm shorter than that of the pump pulses. We also found that this huge nonlinearity works as a compressor that effectively compresses pulse width from 80 to 15.7 fs. Our results clearly show the potential for our G-SWG to greatly boost the speed and capacity of future communications with lower power consumption, and our method will further decrease the required pump laser power because it can be applied to decorate various kinds of waveguides with various two-dimensional materials.

  9. Maximum Likelihood Sequence Detection Receivers for Nonlinear Optical Channels

    Directory of Open Access Journals (Sweden)

    Gabriel N. Maggio


    Full Text Available The space-time whitened matched filter (ST-WMF maximum likelihood sequence detection (MLSD architecture has been recently proposed (Maggio et al., 2014. Its objective is reducing implementation complexity in transmissions over nonlinear dispersive channels. The ST-WMF-MLSD receiver (i drastically reduces the number of states of the Viterbi decoder (VD and (ii offers a smooth trade-off between performance and complexity. In this work the ST-WMF-MLSD receiver is investigated in detail. We show that the space compression of the nonlinear channel is an instrumental property of the ST-WMF-MLSD which results in a major reduction of the implementation complexity in intensity modulation and direct detection (IM/DD fiber optic systems. Moreover, we assess the performance of ST-WMF-MLSD in IM/DD optical systems with chromatic dispersion (CD and polarization mode dispersion (PMD. Numerical results for a 10 Gb/s, 700 km, and IM/DD fiber-optic link with 50 ps differential group delay (DGD show that the number of states of the VD in ST-WMF-MLSD can be reduced ~4 times compared to an oversampled MLSD. Finally, we analyze the impact of the imperfect channel estimation on the performance of the ST-WMF-MLSD. Our results show that the performance degradation caused by channel estimation inaccuracies is low and similar to that achieved by existing MLSD schemes (~0.2 dB.

  10. Hamiltonian chaos in a nonlinear polarized optical beam

    International Nuclear Information System (INIS)

    David, D.; Holm, D.D.; Tratnik, M.V.


    This lecture concerns the applications of ideas about temporal complexity in Hamiltonian systems to the dynamics of an optical laser beam with arbitrary polarization propagating as a travelling wave in a medium with cubically nonlinear polarizability. The authors use methods from the theory of Hamiltonian systems with symmetry to study the geometry of phase space for this optical problem, transforming from C 2 to S 3 x S 1 , first, and then to S 2 x (J,θ) is a symplectic action-angle pair. The bifurcations of the phase portraits of the Hamiltonian motion on S 2 are classified and displayed graphically. These bifurcations take place when either J (the beam intensity) or the optical parameters of the medium are varied. After this bifurcation analysis has shown the existence of various saddle connections on S 2 , the Melnikov method is used to demonstrate analytically that the travelling-wave dynamics of polarized optical laser pulse develops chaotic behavior in the form of Smale horseshoes when propagating through spatially periodic perturbations in the optical parameters of the medium. 23 refs., 7 figs

  11. Dispersive shock waves in nonlinear and atomic optics (United States)

    Kamchatnov, Anatoly


    A brief review is given of dispersive shock waves observed in nonlinear optics and dynamics of Bose-Einstein condensates. The theory of dispersive shock waves is developed on the basis of Whitham modulation theory for various situations taking place in these two fields. In particular, the full classification is established for types of wave structures evolving from initial discontinuities for propagation of long light pulses in fibers with account of steepening effect and for dynamics of the polarization mode in two-component Bose-Einstein condensates.

  12. Dispersive shock waves in nonlinear and atomic optics

    Directory of Open Access Journals (Sweden)

    Kamchatnov Anatoly


    Full Text Available A brief review is given of dispersive shock waves observed in nonlinear optics and dynamics of Bose-Einstein condensates. The theory of dispersive shock waves is developed on the basis of Whitham modulation theory for various situations taking place in these two fields. In particular, the full classification is established for types of wave structures evolving from initial discontinuities for propagation of long light pulses in fibers with account of steepening effect and for dynamics of the polarization mode in two-component Bose-Einstein condensates.

  13. Structure/property relationships in non-linear optical materials

    Energy Technology Data Exchange (ETDEWEB)

    Cole, J.M. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)]|[Durham Univ. (United Kingdom); Howard, J.A.K. [Durham Univ. (United Kingdom); McIntyre, G.J. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)


    The application of neutrons to the study of structure/property relationships in organic non-linear optical materials (NLOs) is described. In particular, charge-transfer effects and intermolecular interactions are investigated. Charge-transfer effects are studied by charge-density analysis and an example of one such investigation is given. The study of intermolecular interactions concentrates on the effects of hydrogen-bonding and an example is given of two structurally similar molecules with very disparate NLO properties, as a result of different types of hydrogen-bonding. (author). 3 refs.

  14. Investigating the thermal environment effects on geometrically nonlinear vibration of smart functionally graded plates

    Energy Technology Data Exchange (ETDEWEB)

    Ebrahimi, Farzad; Rastgoo, Abbas; Bahrami, Mansoor Nikkhah [University of Tehran, Tehran (Iran, Islamic Republic of)


    An analytical solution for a sandwich circular FGM plate coupled with piezoelectric layers under one-dimensional heat conduction is presented. All materials of the device may be of any functional gradients in the direction of thickness. The solution exactly satisfies all the equilibrium conditions and continuity conditions for the stress, displacement and electric displacement as well as electric potential on the interfaces between adjacency layers. A nonlinear static problem is solved first to determine the initial stress state and pre-vibration deformations of the FG plate that is subjected to in-plane forces and applied actuator voltage in thermal environment in the case of simply supported boundary conditions. By adding an incremental dynamic state to the pre-vibration state, the differential equations that govern the nonlinear vibration behavior of pre-stressed piezoelectric coupled FGM plates are derived. The role of thermal environment as well as control effects on nonlinear static deflections and natural frequencies imposed by the piezoelectric actuators using high input voltages are investigated. Numerical examples are provided and simulation results are discussed. Numerical results for FGM plates with a mixture of metal and ceramic are presented in dimensionless forms. The good agreement between the results of this paper and those of the finite element (FE) analyses validated the presented approach. In a parametric study the emphasis is placed on investigating the effect of varying the applied actuator voltage and thermal environment as well as gradient index of FG plate on the dynamics and control characteristics of the structure

  15. Results of including geometric nonlinearities in an aeroelastic model of an F/A-18 (United States)

    Buttrill, Carey S.


    An integrated, nonlinear simulation model suitable for aeroelastic modeling of fixed-wing aircraft has been developed. While the author realizes that the subject of modeling rotating, elastic structures is not closed, it is believed that the equations of motion developed and applied herein are correct to second order and are suitable for use with typical aircraft structures. The equations are not suitable for large elastic deformation. In addition, the modeling framework generalizes both the methods and terminology of non-linear rigid-body airplane simulation and traditional linear aeroelastic modeling. Concerning the importance of angular/elastic inertial coupling in the dynamic analysis of fixed-wing aircraft, the following may be said. The rigorous inclusion of said coupling is not without peril and must be approached with care. In keeping with the same engineering judgment that guided the development of the traditional aeroelastic equations, the effect of non-linear inertial effects for most airplane applications is expected to be small. A parameter does not tell the whole story, however, and modes flagged by the parameter as significant also need to be checked to see if the coupling is not a one-way path, i.e., the inertially affected modes can influence other modes.

  16. Tuning Optical Nonlinearity of Laser-Ablation-Synthesized Silicon Nanoparticles via Doping Concentration

    Directory of Open Access Journals (Sweden)

    Lianwei Chen


    Full Text Available Silicon nanoparticles at different doping concentrations are investigated for tuning their optical nonlinear performance. The silicon nanoparticles are synthesized from doped silicon wafers by pulsed laser ablation. Their dispersions in water are studied for both nonlinear absorption and nonlinear refraction properties. It is found that the optical nonlinear performance can be modified by the doping concentration. Nanoparticles at a higher doping concentration exhibit better saturable absorption performance for femtosecond laser pulse, which is ascribed to the free carrier absorption mechanism.

  17. Electrical and Nonlinear Optical Properties of Novel Organic Materials (United States)

    Navin, Y. Narayana; Bappalige, N.


    The single crystals of organic nonlinear optical material 1-(2, 4-dichlorophenyl) -3-(4-dimethyl amino-phenyl)-2-propenone (DDAP ) and 4—Bromo 2-nitro aniline (BNA) were grown by solvent evaporation technique using ethanol as solvent. The grown crystals were characterized by IR, 1H NMR and mass spectroscopy to confirm the formation of the compound. Electrical property and non linear optical (NLO) properties of these two crystals were studied in detail. DDAP crystals crystallize in the monoclinic system with space group P2l/C. The second harmonic generation efficiency of DDAP is found to be 0.07 times that of KDP and that of BNA is 12 times that of KDP. Conductance of BNA is higher than that of DDAP.

  18. Linear and nonlinear quantum Zeno and anti-Zeno effects in a nonlinear optical coupler (United States)

    Thapliyal, Kishore; Pathak, Anirban; Peřina, Jan


    Quantum Zeno and anti-Zeno effects are studied in a symmetric nonlinear optical coupler, which is composed of two nonlinear (χ(2 )) waveguides that are interacting with each other via the evanescent waves. Both waveguides operate under second harmonic generation. However, to study quantum Zeno and anti-Zeno effects one of them is considered as the system and the other one is considered as the probe. Considering all the fields involved as weak, a completely quantum mechanical description is provided, and the analytic solutions of Heisenberg's equations of motion for all the field modes are obtained using a perturbative technique. Photon number statistics of the second harmonic mode of the system is shown to depend on the presence of the probe, and this dependence is considered as quantum Zeno and anti-Zeno effects. Further, it is established that as a special case of the momentum operator for χ(2 )-χ(2 ) symmetric coupler we can obtain momentum operator of χ(2 )-χ(1 ) asymmetric coupler with linear (χ(1 )) waveguide as the probe, and, in such a particular case, the expressions obtained for Zeno and anti-Zeno effects with nonlinear probe (which we referred to as nonlinear quantum Zeno and anti-Zeno effects) may be reduced to the corresponding expressions with linear probe (which we referred to as the linear quantum Zeno and anti-Zeno effects). Linear and nonlinear quantum Zeno and anti-Zeno effects are rigorously investigated, and it is established that, in the stimulated case, we may switch between quantum Zeno and anti-Zeno effects just by controlling the phase of the second harmonic mode of the system or probe.

  19. Optical and geometrical characteristics of cirrus clouds over a Southern European lidar station

    Directory of Open Access Journals (Sweden)

    E. Giannakaki


    Full Text Available Optical and geometrical characteristics of cirrus clouds over Thessaloniki, Greece (40.6° N, 22.9° E have been determined from the analysis of lidar and radiosonde measurements performed during the period from 2000 to 2006. Cirrus clouds are generally observed in a mid-altitude region ranging from 8.6 to 13 km, with mid-cloud temperatures in the range from −65° to −38°C. The cloud thickness generally ranges from 1 to 5 km and 38{%} of the cases studied have thickness between 2 and 3 km. The retrieval of optical depth and lidar ratio of cirrus clouds is performed using three different methods, taking into account multiple scattering effect. The mean optical depth is found to be 0.31±0.24 and the corresponding mean lidar ratio is 30±17 sr following the scheme of Klett-Fernald method. Sub-visual, thin and opaque cirrus clouds are observed at 3%, 57% and 40% of the measured cases, respectively. A comparison of the results obtained between the three methods shows good agreement. The multiple scattering errors of the measured effective extinction coefficients range from 20 to 60%, depending on cloud optical depth. The temperature and thickness dependencies on optical properties have also been studied in detail. A maximum mid-cloud depth of ~3.5 km is found at temperatures around ~−47.5°C, while there is an indication that optical depth and mean extinction coefficient increases with increasing mid-cloud temperature. A correlation between optical depth and thickness was also found. However, no clear dependence of the lidar ratio values on the cloud temperature and thickness was found.

  20. Molecular studies and plastic optical fiber device structures for nonlinear optical applications (United States)

    Dirk, Carl W.; Nagarur, Aruna R.; Lu, Jin J.; Zhang, Lixia; Kalamegham, Priya; Fonseca, Joe; Gopalan, Saytha; Townsend, Scott; Gonzalez, Gabriel; Craig, Patrick; Rosales, Monica; Green, Leslie; Chan, Karen; Twieg, Robert J.; Ermer, Susan P.; Leung, Doris S.; Lovejoy, Steven M.; Lacroix, Suzanne; Godbout, Nicolas; Monette, Etienne


    Summarized are two project areas: First, the development of a quantitative structure property relationship for analyzing thermal decomposition differential scanning calorimetry data of electro-optic dyes is presented. The QSPR relationship suggest that thermal decomposition can be effectively correlated with structure by considering the kinds of atoms, their hybridization, and their nearest neighbor bonded atoms. Second, the simple preparation of clad plastic optical fibers (POF) is discussed with the intention of use for nonlinear optical applications. We discuss preparation techniques for single core and multiple core POF, and present some recent data on index profiles and the optimization of thermal stability in acrylate-based POF structures.

  1. Relationship between microstructure of the skin surface and surface reflection based on geometric optics. (United States)

    Yoshida, Kenichiro; Miyaki, Masahiro; Ojima, Nobutoshi; Iwata, Kayoko


    The behavior of reflected light in skin affects skin appearance and provides clues as to the internal condition of the skin. Surface topography is one of the central physical factors contributing to surface reflection. We tried to clarify the relationship between microstructure of the skin surface and surface reflection based on geometric optics. Microstructures and surface reflections in the left cheeks of adult females were evaluated. Skin topography was acquired measuring replicas using confocal laser microscopy. Surface topography was used to calculate arithmetical mean deviation of the surface (S(a)), and geometric index from gradient of the surface (S(grad)), which is expected to correlate with the directionality of surface reflection (DoSR) based on geometric optics. A surface reflection image was acquired from differently polarized pictures of a face, and the index of surface reflection (I(obs)) was calculated as the average pixel value of the area of shine. Correlations between indices were then evaluated. S(grad) and S(a) showed significant correlation (preflection from the reflection model than S(a). In addition, S(grad) can explain differences in DoSR for some panelists even in the case of an identical S(a). The topographic element involved in DoSR was extracted from height mapping. S(grad) reflects the ratio of flat area, offering a more effective indicator than S(a) for distinguishing topographic characteristics with respect to surface reflection. Copyright © 2012 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

  2. Geometric subspace updates with applications to online adaptive nonlinear model reduction

    DEFF Research Database (Denmark)

    Zimmermann, Ralf; Peherstorfer, Benjamin; Willcox, Karen


    In many scientific applications, including model reduction and image processing, subspaces are used as ansatz spaces for the low-dimensional approximation and reconstruction of the state vectors of interest. We introduce a procedure for adapting an existing subspace based on information from...... Estimation (GROUSE). We establish for GROUSE a closed-form expression for the residual function along the geodesic descent direction. Specific applications of subspace adaptation are discussed in the context of image processing and model reduction of nonlinear partial differential equation systems....

  3. Optical Computing Using Interference Filters as Nonlinear Optical Logic Gates and Holographic Optical Elements as Optical Interconnects. (United States)

    Wang, Lon A.

    This dissertation experimentally explores digital optical computing and optical interconnects with theoretical supports, from the physics of materials and the optimization of devices to system realization. The trend of optical computing is highlighted with the emphasis on the current development of its basic constituent elements, and a couple of algorithms selected to pave the way for utilizing bistable devices for their optical implementations. Optical bistable devices function as "optical transistors" in optical computing. The physics of dispersive optical bistability is briefly described. Bistable ZnS interference filters are discussed in detail regarding their linear and nonlienar characteristics. The optimization of switching characteristics for a bistable ZnS interference filter is discussed, and experimental results are shown. Symbolic substitution which fully takes advantage of regular optical interconnects constitutes two steps: pattern recognition and symbol scription. Two experiments on two digital pattern recognitions and one on a simple but complete symbolic substitution have been demonstrated. The extension of these experiments is an implementation of a binary adder. A one-bit full adder which is a basic block for a computer has been explored experimentally and demonstrated in an all-optical way. The utilization of a bistable device as a nonlinear decision-making element is further demonstrated in an associative memory experiment by incorporating a Vander Lugt matched filter to discriminate two partial fingerprints. The thresholding function of a bistable device enhances the S/N ratio and helps discrimination in associative memory. As the clocking speed of a computer goes higher, e.g. greater than several GHz, the clock signal distribution and packaging become serious problems in VLSI technology. The use of optical interconnects introduces a possible solution. A unique element for holographic optical interconnects, which combines advantages of

  4. Nonlinear Optics with Tapered Fibers and Magneto-Optically Trapped Rubidium (United States)

    Little, Bethany; Mullarkey, Chris; Howell, John; Vamivakas, Nick; Lin, Qiang


    Tapered optical fibers of sub-wavelength diameter present a promising means of integrating the light-atom interaction into larger scale devices. We present work on a tapered fiber system loaded by a magneto optical trap of Rubidium atoms, in which a combination of red and blue detuned beams create a one-dimensional lattice trap along the fiber. The same fiber is used for interacting with the atoms in the trap via the evanescent fields of light propagating along the fiber. Light storage has been demonstrated in a similar system with Cesium, and we believe that much nonlinear optics remains to be explored in this regime. We also plan to see how these nonlinear effects can be enhanced with the addition of a micro-resonator such as the ones in.

  5. Mechanism of large optical nonlinearity in gold nanoparticle films. (United States)

    Mirza, I; McCloskey, D; Blau, W J; Lunney, J G


    The Z-scan technique, using femtosecond (fs) laser pulses at 1480 nm laser pulses, was used to measure the nonlinear optical properties of gold (Au) nanoparticle (NP) films made by both nanosecond (ns) and fs pulsed laser deposition (PLD) in vacuum. At irradiance levels of 1×10 12   Wm -2 , the ns-PLD films displayed induced absorption with β=4×10 -5   mW -1 , and a negative lensing effect with n 2 =-4.7×10 -11   m 2  W -1 with somewhat smaller values for the fs-PLD films. These values of n 2 imply an unphysically large change in the real part of the refractive index, demonstrating the need to take account of nonlinear changes of the Fresnel coefficients and multiple beam interference in Z-scan measurements on nanoscale films. Following this approach, the Z-scan observations were analyzed to determine the effective complex refractive index of the NP film at high irradiance. It appears that at high irradiance the NP film behaves as a metal, while at low irradiance it behaves as a low-loss dielectric. Thus, it is conjectured that, for high irradiance near the waist of the Z-scan laser beam, laser driven electron tunneling between NPs gives rise to metal-like optical behavior.

  6. A NURBS-based finite element model applied to geometrically nonlinear elastodynamics using a corotational approach

    KAUST Repository

    Espath, L. F R


    A numerical model to deal with nonlinear elastodynamics involving large rotations within the framework of the finite element based on NURBS (Non-Uniform Rational B-Spline) basis is presented. A comprehensive kinematical description using a corotational approach and an orthogonal tensor given by the exact polar decomposition is adopted. The state equation is written in terms of corotational variables according to the hypoelastic theory, relating the Jaumann derivative of the Cauchy stress to the Eulerian strain rate.The generalized-α method (Gα) method and Generalized Energy-Momentum Method with an additional parameter (GEMM+ξ) are employed in order to obtain a stable and controllable dissipative time-stepping scheme with algorithmic conservative properties for nonlinear dynamic analyses.The main contribution is to show that the energy-momentum conservation properties and numerical stability may be improved once a NURBS-based FEM in the spatial discretization is used. Also it is shown that high continuity can postpone the numerical instability when GEMM+ξ with consistent mass is employed; likewise, increasing the continuity class yields a decrease in the numerical dissipation. A parametric study is carried out in order to show the stability and energy budget in terms of several properties such as continuity class, spectral radius and lumped as well as consistent mass matrices.

  7. Nonlinear Conductivity of Geometrically Frustrated Iridate Ca5Ir3O12 (United States)

    Matsuhira, Kazuyuki; Nakamura, Kazuma; Yasukuni, Yuki; Yoshimoto, Yoshihide; Hirai, Daigorou; Hiroi, Zenji


    We report the discovery of nonlinear conductivity along the c-axis in a single crystal of Ca5Ir3O12, which indicates a semiconducting behavior with a narrow band gap of ˜0.2 eV. The resistivity decreases with increase in the applied current. This nonlinearity is reversible with the direction of current. We also show the ab initio density functional band structures and the Fermi surface. We found that the spin-orbit interactions result in an appreciable change in the low-energy electronic structure; the interaction splits the metallic bands and leads to a pocket-like band structure, thus reducing the metallic trend. The size of the spin-orbit interaction is estimated as ˜0.3 eV, which is large enough to be comparable to the valence bandwidth of ˜0.5 eV. The Fermi surface exhibits a sheet structure along the c*-axis, due to the 1D chain structure of edge-sharing IrO6.

  8. Geometric nonlinear dynamic analysis of curved beams using curved beam element (United States)

    Pan, Ke-Qi; Liu, Jin-Yang


    Instead of using the previous straight beam element to approximate the curved beam, in this paper, a curvilinear coordinate is employed to describe the deformations, and a new curved beam element is proposed to model the curved beam. Based on exact nonlinear strain-displacement relation, virtual work principle is used to derive dynamic equations for a rotating curved beam, with the effects of axial extensibility, shear deformation and rotary inertia taken into account. The constant matrices are solved numerically utilizing the Gauss quadrature integration method. Newmark and Newton-Raphson iteration methods are adopted to solve the differential equations of the rigid-flexible coupling system. The present results are compared with those obtained by commercial programs to validate the present finite method. In order to further illustrate the convergence and efficiency characteristics of the present modeling and computation formulation, comparison of the results of the present formulation with those of the ADAMS software are made. Furthermore, the present results obtained from linear formulation are compared with those from nonlinear formulation, and the special dynamic characteristics of the curved beam are concluded by comparison with those of the straight beam.

  9. Geometric Structure of the Classical Lagrange-d’Alambert Principle and Its Application to Integrable Nonlinear Dynamical Systems

    Directory of Open Access Journals (Sweden)

    Anatolij K. Prykarpatski


    Full Text Available The classical Lagrange-d’Alembert principle had a decisive influence on formation of modern analytical mechanics which culminated in modern Hamilton and Poisson mechanics. Being mainly interested in the geometric interpretation of this principle, we devoted our review to its deep relationships to modern Lie-algebraic aspects of the integrability theory of nonlinear heavenly type dynamical systems and its so called Lax-Sato counterpart. We have also analyzed old and recent investigations of the classical M. A. Buhl problem of describing compatible linear vector field equations, its general M.G. Pfeiffer and modern Lax-Sato type special solutions. Especially we analyzed the related Lie-algebraic structures and integrability properties of a very interesting class of nonlinear dynamical systems called the dispersionless heavenly type equations, which were initiated by Plebański and later analyzed in a series of articles. As effective tools the AKS-algebraic and related R -structure schemes are used to study the orbits of the corresponding co-adjoint actions, which are intimately related to the classical Lie-Poisson structures on them. It is demonstrated that their compatibility condition coincides with the corresponding heavenly type equations under consideration. It is also shown that all these equations originate in this way and can be represented as a Lax-Sato compatibility condition for specially constructed loop vector fields on the torus. Typical examples of such heavenly type equations, demonstrating in detail their integrability via the scheme devised herein, are presented.

  10. Geometric Nonlinear Meshless Analysis of Ribbed Rectangular Plates Based on the FSDT and the Moving Least-Squares Approximation

    Directory of Open Access Journals (Sweden)

    L. X. Peng


    Full Text Available Based on the first-order shear deformation theory (FSDT and the moving least-squares approximation, a new meshless model to study the geometric nonlinear problem of ribbed rectangular plates is presented. Considering the plate and the ribs separately, the displacement field, the stress, and strain of the plate and the ribs are obtained according to the moving least-squares approximation, the von Karman large deflection theory, and the FSDT. The ribs are attached to the plate by considering the displacement compatible condition along the connections between the ribs and the plate. The virtual strain energy formulation of the plate and the ribs is derived separately, and the nonlinear equilibrium equation of the entire ribbed plate is given by the virtual work principle. In the new meshless model for ribbed plates, there is no limitation to the rib position; for example, the ribs need not to be placed along the mesh lines of the plate as they need to be in FEM, and the change of rib positions will not lead to remeshing of the plate. The proposed model is compared with the FEM models from pieces of literature and ANSYS in several numerical examples, which proves the accuracy of the model.

  11. Geometrically Nonlinear Field Fracture Mechanics and Crack Nucleation, Application to Strain Localization Fields in Al-Cu-Li Aerospace Alloys. (United States)

    Gupta, Satyapriya; Taupin, Vincent; Fressengeas, Claude; Jrad, Mohamad


    The displacement discontinuity arising between crack surfaces is assigned to smooth densities of crystal defects referred to as disconnections, through the incompatibility of the distortion tensor. In a dual way, the disconnections are defined as line defects terminating surfaces where the displacement encounters a discontinuity. A conservation statement for the crack opening displacement provides a framework for disconnection dynamics in the form of transport laws. A similar methodology applied to the discontinuity of the plastic displacement due to dislocations results in the concurrent involvement of dislocation densities in the analysis. Non-linearity of the geometrical setting is assumed for defining the elastic distortion incompatibility in the presence of both dislocations and disconnections, as well as for their transport. Crack nucleation in the presence of thermally-activated fluctuations of the atomic order is shown to derive from this nonlinearity in elastic brittle materials, without any algorithmic rule or ad hoc material parameter. Digital image correlation techniques applied to the analysis of tensile tests on ductile Al-Cu-Li samples further demonstrate the ability of the disconnection density concept to capture crack nucleation and relate strain localization bands to consistent disconnection fields and to the eventual occurrence of complex and combined crack modes in these alloys.

  12. Cascadable all-optical inverter based on a nonlinear vertical-cavity semiconductor optical amplifier. (United States)

    Zhang, Haijiang; Wen, Pengyue; Esener, Sadik


    We report, for the first time to our knowledge, the operation of a cascadable, low-optical-switching-power(~10 microW) small-area (~100 microm(2)) high-speed (80 ps fall time) all-optical inverter. This inverter employs cross-gain modulation, polarization gain anisotropy, and highly nonlinear gain characteristics of an electrically pumped vertical-cavity semiconductor optical amplifier (VCSOA). The measured transfer characteristics of such an optical inverter resemble those of standard electronic metal-oxide semiconductor field-effect transistor-based inverters exhibiting high noise margin and high extinction ratio (~9.3 dB), making VCSOAs an ideal building block for all-optical logic and memory.

  13. Differential Polarization Nonlinear Optical Microscopy with Adaptive Optics Controlled Multiplexed Beams

    Directory of Open Access Journals (Sweden)

    Virginijus Barzda


    Full Text Available Differential polarization nonlinear optical microscopy has the potential to become an indispensable tool for structural investigations of ordered biological assemblies and microcrystalline aggregates. Their microscopic organization can be probed through fast and sensitive measurements of nonlinear optical signal anisotropy, which can be achieved with microscopic spatial resolution by using time-multiplexed pulsed laser beams with perpendicular polarization orientations and photon-counting detection electronics for signal demultiplexing. In addition, deformable membrane mirrors can be used to correct for optical aberrations in the microscope and simultaneously optimize beam overlap using a genetic algorithm. The beam overlap can be achieved with better accuracy than diffraction limited point-spread function, which allows to perform polarization-resolved measurements on the pixel-by-pixel basis. We describe a newly developed differential polarization microscope and present applications of the differential microscopy technique for structural studies of collagen and cellulose. Both, second harmonic generation, and fluorescence-detected nonlinear absorption anisotropy are used in these investigations. It is shown that the orientation and structural properties of the fibers in biological tissue can be deduced and that the orientation of fluorescent molecules (Congo Red, which label the fibers, can be determined. Differential polarization microscopy sidesteps common issues such as photobleaching and sample movement. Due to tens of megahertz alternating polarization of excitation pulses fast data acquisition can be conveniently applied to measure changes in the nonlinear signal anisotropy in dynamically changing in vivo structures.

  14. Differential polarization nonlinear optical microscopy with adaptive optics controlled multiplexed beams. (United States)

    Samim, Masood; Sandkuijl, Daaf; Tretyakov, Ian; Cisek, Richard; Barzda, Virginijus


    Differential polarization nonlinear optical microscopy has the potential to become an indispensable tool for structural investigations of ordered biological assemblies and microcrystalline aggregates. Their microscopic organization can be probed through fast and sensitive measurements of nonlinear optical signal anisotropy, which can be achieved with microscopic spatial resolution by using time-multiplexed pulsed laser beams with perpendicular polarization orientations and photon-counting detection electronics for signal demultiplexing. In addition, deformable membrane mirrors can be used to correct for optical aberrations in the microscope and simultaneously optimize beam overlap using a genetic algorithm. The beam overlap can be achieved with better accuracy than diffraction limited point-spread function, which allows to perform polarization-resolved measurements on the pixel-by-pixel basis. We describe a newly developed differential polarization microscope and present applications of the differential microscopy technique for structural studies of collagen and cellulose. Both, second harmonic generation, and fluorescence-detected nonlinear absorption anisotropy are used in these investigations. It is shown that the orientation and structural properties of the fibers in biological tissue can be deduced and that the orientation of fluorescent molecules (Congo Red), which label the fibers, can be determined. Differential polarization microscopy sidesteps common issues such as photobleaching and sample movement. Due to tens of megahertz alternating polarization of excitation pulses fast data acquisition can be conveniently applied to measure changes in the nonlinear signal anisotropy in dynamically changing in vivo structures.

  15. Differential Polarization Nonlinear Optical Microscopy with Adaptive Optics Controlled Multiplexed Beams (United States)

    Samim, Masood; Sandkuijl, Daaf; Tretyakov, Ian; Cisek, Richard; Barzda, Virginijus


    Differential polarization nonlinear optical microscopy has the potential to become an indispensable tool for structural investigations of ordered biological assemblies and microcrystalline aggregates. Their microscopic organization can be probed through fast and sensitive measurements of nonlinear optical signal anisotropy, which can be achieved with microscopic spatial resolution by using time-multiplexed pulsed laser beams with perpendicular polarization orientations and photon-counting detection electronics for signal demultiplexing. In addition, deformable membrane mirrors can be used to correct for optical aberrations in the microscope and simultaneously optimize beam overlap using a genetic algorithm. The beam overlap can be achieved with better accuracy than diffraction limited point-spread function, which allows to perform polarization-resolved measurements on the pixel-by-pixel basis. We describe a newly developed differential polarization microscope and present applications of the differential microscopy technique for structural studies of collagen and cellulose. Both, second harmonic generation, and fluorescence-detected nonlinear absorption anisotropy are used in these investigations. It is shown that the orientation and structural properties of the fibers in biological tissue can be deduced and that the orientation of fluorescent molecules (Congo Red), which label the fibers, can be determined. Differential polarization microscopy sidesteps common issues such as photobleaching and sample movement. Due to tens of megahertz alternating polarization of excitation pulses fast data acquisition can be conveniently applied to measure changes in the nonlinear signal anisotropy in dynamically changing in vivo structures. PMID:24022688

  16. The nonlinear Schrödinger equation singular solutions and optical collapse

    CERN Document Server

    Fibich, Gadi


    This book is an interdisciplinary introduction to optical collapse of laser beams, which is modelled by singular (blow-up) solutions of the nonlinear Schrödinger equation. With great care and detail, it develops the subject including the mathematical and physical background and the history of the subject. It combines rigorous analysis, asymptotic analysis, informal arguments, numerical simulations, physical modelling, and physical experiments. It repeatedly emphasizes the relations between these approaches, and the intuition behind the results. The Nonlinear Schrödinger Equation will be useful to graduate students and researchers in applied mathematics who are interested in singular solutions of partial differential equations, nonlinear optics and nonlinear waves, and to graduate students and researchers in physics and engineering who are interested in nonlinear optics and Bose-Einstein condensates. It can be used for courses on partial differential equations, nonlinear waves, and nonlinear optics. Gadi Fib...

  17. A contribution to the physically and geometrically nonlinear computer analysis of general reinforced concrete shells

    International Nuclear Information System (INIS)

    Zahlten, W.


    Starting from a Kirchhoff-Love type shell theory of finite rotations a layered shell element for reinforced concrete is developed. The plastic-fracturing theory due to Bazant/Kim is used to describe the uncracked concrete. Tension cracking is controlled by a principle tensile stress criterion. An elasto-plastic law with kinematic hardening models the reinforcing steel. The tension stiffening concept of Gilbert/Warner allows an averaged consideration of the concrete between cracks. By discretization of the displacement field the element matrices are obtained which are derived via tensor notation. The nonlinear structural response is computed by incremental-iterative path-tracing algorithms. The range of applicability of the model is finally be proven by several examples with time-invariant and time-dependent loading. (orig.) [de

  18. Enhanced poling efficiency in highly thermal and photostable nonlinear optical chromophores

    NARCIS (Netherlands)

    Faccini, M.; Balakrishnan, M.; Diemeer, Mart; Hu, Zhi-Peng; Clays, Koen; Asselberghs, Inge; Leinse, Arne; Driessen, A.; Reinhoudt, David; Verboom, Willem

    A series of nonlinear optical chromophores based on the highly thermal and photostable tricyanovinylidenediphenylaminobenzene (TCVDPA) was synthesized and their thermal and optical properties were investigated. Modification of the TCVDPA chromophore with bulky groups provides reduction of

  19. Nonlinear optical properties of natural laccaic acid dye studied using Z-scan technique

    CSIR Research Space (South Africa)

    Zongo, S


    Full Text Available We have investigated the nonlinear optical properties, including the optical limiting behaviour for five different concentrations of laccaic acid dye in solution and a thin film obtained through doping in poly (methyl methacrylate) (PMMA) polymer...

  20. A novel method measuring optical fiber nonlinear coefficient based on XPM (United States)

    Zhang, Shuangxi; Wu, Xuqiang; Ai, Fei; Zhang, Chengmei; Zhang, Bo; Yu, Benli


    In optic communication systems, the nonlinear effect of the optical fiber is of great importance. There are several methods measuring optical fiber nonlinear coefficient. A novel method measuring optical fiber nonlinear coefficient is proposed, which is based on a Mach-Zehnder interferometer fabricated with 3×3 coupler, polarization controller and so on. According to cross phase modulation (XPM), when two optical waves are injected into the same optical fiber, the phase of one optical wave will be changed because of the other one. So a sinusoidal phase signal will be generated through coupling a sinusoidal modulated high-power laser into one arm of the interferometer, and then the three outputs of the interferometer will contain the sinusoidal phase signal. According to the characteristic of the 3×3 coupler, the phase difference between the three outputs is 2π / 3 . Through mathematics disposition of the three outputs of the interferometer, a couple of orthogonal signals can be yielded. Then the amplitude of the sinusoidal phase signal can be demodulated accurately by arctan method. The length of the optical fiber and the power of the laser can be measured easily, according to expression about the nonlinear phase shift induced by XPM, the optical fiber nonlinear coefficient of certain wavelength will be calculated. The optical fiber nonlinear effect is simulated by the software optisystem, and the process measuring the optical fiber nonlinear coefficient is analyzed in detail based on the schematic design.

  1. Third order optical nonlinearity and optical limiting studies of propane hydrazides (United States)

    Naseema, K.; Manjunatha, K. B.; Sujith, K. V.; Umesh, G.; Kalluraya, Balakrishna; Rao, Vijayalakshmi


    Four hydrazones, 2-(4-isobutylphenyl)-N'-[phenylmethylene] propanehydrazide (P1), 2-(4-isobutylphenyl)-N'-[(4- tolyl)methylene] propane hydrazide (P2), 2-(4-isobutylphenyl)-N'-[1-(4- chlorophenyl)ethylidene] propanehydrazide (P3) and 2-(4-isobutylphenyl)-N'-[1-(4-Nitrrophenyl)ethylidene] propane hydrazide (P4) were synthesized and their third order nonlinear optical properties have been investigated using a single beam Z-scan technique with nanosecond laser pulses at 532 nm. The measurement on the compound-P1 is not reported as there is no detectable nonlinear response. Open aperture data of the other three compounds indicate two photon absorption at this wavelength. The nonlinear refractive index n2, nonlinear absorption coefficient β, magnitude of effective third order susceptibility χ(3), the second order hyperpolarizability γh and the coupling factor ρ have been estimated. The values obtained are comparable with the values obtained for 4-methoxy chalcone derivatives and dibenzylideneacetone derivatives. The experimentally determined values of β, n2, Re χ(3) and Im χ(3), γh and ρ of the compound-P4 are 1.42 cm/GW, -0.619 × 10-11 esu, -0.663 × 10-13 esu, 0.22 × 10-13 esu, 0.34 × 10-32 esu and 0.33 respectively. Further the compound-P4 exhibited the best optical power limiting behavior at 532 nm among the compounds studied. Our studies suggest that compounds P2, P3 and P4 are potential candidates for the optical device applications such as optical limiters and optical switches.

  2. A geometrically nonlinear shell element for hygrothermorheologically simple linear viscoelastic composites

    Energy Technology Data Exchange (ETDEWEB)



    A triangular flat shell element for large deformation analysis of linear viscoelastic laminated composites is presented. Hygrothermorheologically simple materials are considered for which a change in the hygrothermal environment results in a horizontal shifting of the relaxation moduli curves on a log time scale, in addition to the usual hygrothermal loads. Recurrence relations are developed and implemented for the evaluation of the viscoelastic memory loads. The nonlinear deformation process is computed using an incremental/iterative approach with the Newton-Raphson Method used to find the incremental displacements in each step. The presented numerical examples consider the large deformation and stability of linear viscoelastic structures under deformation-independent mechanical loads, deformation-dependent pressure loads, and thermal loads. Unlike elastic structures that have a single critical load value associated with a given snapping of buckling instability phenomenon, viscoelastic structures will usually exhibit a particular instability for a range of applied loads over a range of critical times. Both creep buckling and snap-through examples are presented here. In some cases, viscoelastic results are also obtained using the quasielastic method in which load-history effects are ignored, and time-varying viscoelastic properties are simply used in a series of elastic problems. The presented numerical examples demonstrate the capability and accuracy of the formulation.

  3. Explicit Nonlinear Finite Element Geometric Analysis of Parabolic Leaf Springs under Various Loads

    Directory of Open Access Journals (Sweden)

    Y. S. Kong


    Full Text Available This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability.

  4. A uniform geometrical optics and an extended uniform geometrical theory of diffraction for evaluating high frequency EM fields near smooth caustics and composite shadow boundaries (United States)

    Constantinides, E. D.; Marhefka, R. J.


    A uniform geometrical optics (UGO) and an extended uniform geometrical theory of diffraction (EUTD) are developed for evaluating high frequency electromagnetic (EM) fields within transition regions associated with a two and three dimensional smooth caustic of reflected rays and a composite shadow boundary formed by the caustic termination or the confluence of the caustic with the reflection shadow boundary (RSB). The UGO is a uniform version of the classic geometrical optics (GO). It retains the simple ray optical expressions of classic GO and employs a new set of uniform reflection coefficients. The UGO also includes a uniform version of the complex GO ray field that exists on the dark side of the smooth caustic. The EUTD is an extension of the classic uniform geometrical theory of diffraction (UTD) and accounts for the non-ray optical behavior of the UGO reflected field near caustics by using a two-variable transition function in the expressions for the edge diffraction coefficients. It also uniformly recovers the classic UTD behavior of the edge diffracted field outside the composite shadow boundary transition region. The approach employed for constructing the UGO/EUTD solution is based on a spatial domain physical optics (PO) radiation integral representation for the fields which is then reduced using uniform asymptotic procedures. The UGO/EUTD analysis is also employed to investigate the far-zone RCS problem of plane wave scattering from two and three dimensional polynomial defined surfaces, and uniform reflection, zero-curvature, and edge diffraction coefficients are derived. Numerical results for the scattering and diffraction from cubic and fourth order polynomial strips are also shown and the UGO/EUTD solution is validated by comparison to an independent moment method (MM) solution. The UGO/EUTD solution is also compared with the classic GO/UTD solution. The failure of the classic techniques near caustics and composite shadow boundaries is clearly

  5. Electro-optic side-chain polyimide system with large optical nonlinearity and high thermal stability (United States)

    Sotoyama, Wataru; Tatsuura, Satoshi; Yoshimura, Tetsuzo


    We report electro-optic (EO) efficiency and thermal stability of a poled polyimide system with nonlinear optical dyes as side chains. The side-chain polyimide system is synthesized from a dianhydride containing azobenzene dye and a diamine. The dye in the polymer is chemically stable for temperatures below 250 °C. The polymer can be poled simultaneously with or after imidization of the polyamic acid. Our sample poled after imidization shows a large EO coefficient (r33=10.8 pm/V at λ=1.3 μm) and long-term thermal stability at 120 °C.

  6. Growth, structural, optical, thermal and mechanical studies on 4-Aminopyridinium monophthalate: A novel nonlinear optical crystal (United States)

    Marudhu, G.; Krishnan, S.; Palanichamy, M.


    A novel nonlinear optical crystal of 4-Aminopyridinium monophthalate (4-APMP) was grown by slow evaporation technique using methanol as solvent. Single crystal X-ray diffraction analysis confirms that the grown crystal belongs to orthorhombic system. The presence of functional groups was qualitatively determined by FTIR analysis. The optical absorption studies reveal very low absorption in the entire visible region. The fluorescence emission spectrum shows the emission is in blue region. The thermal stability of the grown crystal is found to be around 197.2 °C. The SHG efficiency of the grown crystal is found to be 1.1 times than that of KDP crystals.

  7. An integrated nonlinear optical loop mirror in silicon photonics for all-optical signal processing

    Directory of Open Access Journals (Sweden)

    Zifei Wang


    Full Text Available The nonlinear optical loop mirror (NOLM has been studied for several decades and has attracted considerable attention for applications in high data rate optical communications and all-optical signal processing. The majority of NOLM research has focused on silica fiber-based implementations. While various fiber designs have been considered to increase the nonlinearity and manage dispersion, several meters to hundreds of meters of fiber are still required. On the other hand, there is increasing interest in developing photonic integrated circuits for realizing signal processing functions. In this paper, we realize the first-ever passive integrated NOLM in silicon photonics and demonstrate its application for all-optical signal processing. In particular, we show wavelength conversion of 10 Gb/s return-to-zero on-off keying (RZ-OOK signals over a wavelength range of 30 nm with error-free operation and a power penalty of less than 2.5 dB, we achieve error-free nonreturn to zero (NRZ-to-RZ modulation format conversion at 10 Gb/s also with a power penalty of less than 2.8 dB, and we obtain error-free all-optical time-division demultiplexing of a 40 Gb/s RZ-OOK data signal into its 10 Gb/s tributary channels with a maximum power penalty of 3.5 dB.

  8. Approximate Forward Difference Equations for the Lower Order Non-Stationary Statistics of Geometrically Non-Linear Systems subject to Random Excitation

    DEFF Research Database (Denmark)

    Köylüoglu, H. U.; Nielsen, Søren R. K.; Cakmak, A. S.

    Geometrically non-linear multi-degree-of-freedom (MDOF) systems subject to random excitation are considered. New semi-analytical approximate forward difference equations for the lower order non-stationary statistical moments of the response are derived from the stochastic differential equations o...... of motion, and, the accuracy of these equations is numerically investigated. For stationary excitations, the proposed method computes the stationary statistical moments of the response from the solution of non-linear algebraic equations.......Geometrically non-linear multi-degree-of-freedom (MDOF) systems subject to random excitation are considered. New semi-analytical approximate forward difference equations for the lower order non-stationary statistical moments of the response are derived from the stochastic differential equations...

  9. Collision of Akhmediev Breathers in Nonlinear Fiber Optics

    Directory of Open Access Journals (Sweden)

    B. Frisquet


    Full Text Available We report here a novel fiber-based test bed using tailored spectral shaping of an optical-frequency comb to excite the formation of two Akhmediev breathers that collide during propagation. We have found specific initial conditions by controlling the phase and velocity differences between breathers that lead, with certainty, to their efficient collision and the appearance of a giant-amplitude wave. Temporal and spectral characteristics of the collision dynamics are in agreement with the corresponding analytical solution. We anticipate that experimental evidence of breather-collision dynamics is of fundamental importance in the understanding of extreme ocean waves and in other disciplines driven by the continuous nonlinear Schrödinger equation.

  10. Compensation of scale factor nonlinearity in resonator fiber optic gyro (United States)

    Zhi, Yinzhou; Feng, Lishuang; Wang, Junjie; Tang, Yichuang


    Scale factor nonlinearity (SFN) and dynamic range (DR) are the two significant parameters used to evaluate the performance of a resonator fiber optic gyro (RFOG). The inherent SFN of an open-loop RFOG with triangular phase modulation is first analyzed theoretically, and its relationship with the DR is simulated, showing that the DR is significantly constrained by the SFN. For our system, when the SFN is 1%, the DR is less than ±82 deg/s. To decrease the SFN in a certain DR, a real-time compensation method based on a field-programmable gate array is proposed. The compensation model is set up and the compensation scheme is illustrated. With the proposed method, the SFN of the RFOG is decreased from 1.53% to 0.057% with a DR of ±100 deg/s.

  11. Moyal phase-space analysis of nonlinear optical Kerr media

    International Nuclear Information System (INIS)

    Osborn, T A; Marzlin, Karl-Peter


    Nonlinear optical media of Kerr type are described by a particular version of an anharmonic quantum harmonic oscillator. The dynamics of this system can be described using the Moyal equations of motion, which correspond to a quantum phase-space representation of the Heisenberg equations of motion. For the Kerr system we derive exact solutions of the Moyal equations for an irreducible set of observables. These Moyal solutions incorporate the asymptotics of the classical limit in a simple, explicit form. An unusual feature of these solutions is that they exhibit periodic singularities in the time variable. These singularities are removed by the phase-space averaging required to construct the expectation value for an arbitrary initial state. Nevertheless, for strongly number-squeezed initial states the effects of the singularity remain observable.

  12. Regularized linearization for quantum nonlinear optical cavities: application to degenerate optical parametric oscillators. (United States)

    Navarrete-Benlloch, Carlos; Roldán, Eugenio; Chang, Yue; Shi, Tao


    Nonlinear optical cavities are crucial both in classical and quantum optics; in particular, nowadays optical parametric oscillators are one of the most versatile and tunable sources of coherent light, as well as the sources of the highest quality quantum-correlated light in the continuous variable regime. Being nonlinear systems, they can be driven through critical points in which a solution ceases to exist in favour of a new one, and it is close to these points where quantum correlations are the strongest. The simplest description of such systems consists in writing the quantum fields as the classical part plus some quantum fluctuations, linearizing then the dynamical equations with respect to the latter; however, such an approach breaks down close to critical points, where it provides unphysical predictions such as infinite photon numbers. On the other hand, techniques going beyond the simple linear description become too complicated especially regarding the evaluation of two-time correlators, which are of major importance to compute observables outside the cavity. In this article we provide a regularized linear description of nonlinear cavities, that is, a linearization procedure yielding physical results, taking the degenerate optical parametric oscillator as the guiding example. The method, which we call self-consistent linearization, is shown to be equivalent to a general Gaussian ansatz for the state of the system, and we compare its predictions with those obtained with available exact (or quasi-exact) methods. Apart from its operational value, we believe that our work is valuable also from a fundamental point of view, especially in connection to the question of how far linearized or Gaussian theories can be pushed to describe nonlinear dissipative systems which have access to non-Gaussian states.

  13. Nonlinear Optical Magnetism Revealed by Second-Harmonic Generation in Nanoantennas. (United States)

    Kruk, Sergey S; Camacho-Morales, Rocio; Xu, Lei; Rahmani, Mohsen; Smirnova, Daria A; Wang, Lei; Tan, Hark Hoe; Jagadish, Chennupati; Neshev, Dragomir N; Kivshar, Yuri S


    Nonlinear effects at the nanoscale are usually associated with the enhancement of electric fields in plasmonic structures. Recently emerged new platform for nanophotonics based on high-index dielectric nanoparticles utilizes optically induced magnetic response via multipolar Mie resonances and provides novel opportunities for nanoscale nonlinear optics. Here, we observe strong second-harmonic generation from AlGaAs nanoantennas driven by both electric and magnetic resonances. We distinguish experimentally the contribution of electric and magnetic nonlinear response by analyzing the structure of polarization states of vector beams in the second-harmonic radiation. We control continuously the transition between electric and magnetic nonlinearities by tuning polarization of the optical pump. Our results provide a direct observation of nonlinear optical magnetism through selective excitation of multipolar nonlinear modes in nanoantennas.

  14. Electron-related linear and nonlinear optical responses in vertically coupled triangular quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Orozco, J.C. [Unidad Académica de Física. Universidad Autónoma de Zacatecas, Calzada Solidaridad esquina con Paseo la Bufa S/N, C.P. 98060. Zacatecas, Zac. (Mexico); Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Mora-Ramos, M.E. [Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Ave. Universidad 1001, CP 62209, Cuernavaca, Morelos (Mexico); Duque, C.A., E-mail: [Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia)


    The conduction band states of GaAs-based vertically coupled double triangular quantum dots in two dimensions are investigated within the effective mass and parabolic approximation, using a diagonalization procedure to solve the corresponding Schrödinger-like equation. The effect of an externally applied static electric field is included in the calculation, and the variation of the lowest confined energy levels as a result of the change of the field strength is reported for different geometrical setups. The linear and nonlinear optical absorptions and the relative change of the refractive index, associated with the energy transition between the ground and the first excited state in the system, are studied as a function of the incident light frequency for distinct configurations of inter-dot distance and electric field intensities. The blueshift of the resonant absorption peaks is detected as a consequence of the increment in the field intensity, whereas the opposite effect is obtained from the increase of inter-dot vertical distance. It is also shown that for large enough values of the electric field there is a quenching of the optical absorption due to field-induced change of symmetry of the first excited state wavefunction, in the case of triangular dots of equal shape and size.

  15. Benzothiazolium Single Crystals: A New Class of Nonlinear Optical Crystals with Efficient THz Wave Generation. (United States)

    Lee, Seung-Heon; Lu, Jian; Lee, Seung-Jun; Han, Jae-Hyun; Jeong, Chan-Uk; Lee, Seung-Chul; Li, Xian; Jazbinšek, Mojca; Yoon, Woojin; Yun, Hoseop; Kang, Bong Joo; Rotermund, Fabian; Nelson, Keith A; Kwon, O-Pil


    Highly efficient nonlinear optical organic crystals are very attractive for various photonic applications including terahertz (THz) wave generation. Up to now, only two classes of ionic crystals based on either pyridinium or quinolinium with extremely large macroscopic optical nonlinearity have been developed. This study reports on a new class of organic nonlinear optical crystals introducing electron-accepting benzothiazolium, which exhibit higher electron-withdrawing strength than pyridinium and quinolinium in benchmark crystals. The benzothiazolium crystals consisting of new acentric core HMB (2-(4-hydroxy-3-methoxystyryl)-3-methylbenzo[d]thiazol-3-ium) exhibit extremely large macroscopic optical nonlinearity with optimal molecular ordering for maximizing the diagonal second-order nonlinearity. HMB-based single crystals prepared by simple cleaving method satisfy all required crystal characteristics for intense THz wave generation such as large crystal size with parallel surfaces, moderate thickness and high optical quality with large optical transparency range (580-1620 nm). Optical rectification of 35 fs pulses at the technologically very important wavelength of 800 nm in 0.26 mm thick HMB crystal leads to one order of magnitude higher THz wave generation efficiency with remarkably broader bandwidth compared to standard inorganic 0.5 mm thick ZnTe crystal. Therefore, newly developed HMB crystals introducing benzothiazolium with extremely large macroscopic optical nonlinearity are very promising materials for intense broadband THz wave generation and other nonlinear optical applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Exploring lipids with nonlinear optical microscopy in multiple biological systems (United States)

    Alfonso-Garcia, Alba

    Lipids are crucial biomolecules for the well being of humans. Altered lipid metabolism may give rise to a variety of diseases that affect organs from the cardiovascular to the central nervous system. A deeper understanding of lipid metabolic processes would spur medical research towards developing precise diagnostic tools, treatment methods, and preventive strategies for reducing the impact of lipid diseases. Lipid visualization remains a complex task because of the perturbative effect exerted by traditional biochemical assays and most fluorescence markers. Coherent Raman scattering (CRS) microscopy enables interrogation of biological samples with minimum disturbance, and is particularly well suited for label-free visualization of lipids, providing chemical specificity without compromising on spatial resolution. Hyperspectral imaging yields large datasets that benefit from tailored multivariate analysis. In this thesis, CRS microscopy was combined with Raman spectroscopy and other label-free nonlinear optical techniques to analyze lipid metabolism in multiple biological systems. We used nonlinear Raman techniques to characterize Meibum secretions in the progression of dry eye disease, where the lipid and protein contributions change in ratio and phase segregation. We employed similar tools to examine lipid droplets in mice livers aboard a spaceflight mission, which lose their retinol content contributing to the onset of nonalcoholic fatty-liver disease. We also focused on atherosclerosis, a disease that revolves around lipid-rich plaques in arterial walls. We examined the lipid content of macrophages, whose variable phenotype gives rise to contrasting healing and inflammatory activities. We also proposed new label-free markers, based on lifetime imaging, for macrophage phenotype, and to detect products of lipid oxidation. Cholesterol was also detected in hepatitis C virus infected cells, and in specific strains of age-related macular degeneration diseased cells by

  17. Evaluation of third order nonlinear optical parameters of CdS/PVA nanocomposite

    International Nuclear Information System (INIS)

    Sharma, Mamta; Tripathi, S. K.


    CdS nanoparticles dispersed in PVA are prepared by Chemical method at room temperature. The nonlinear optical parameters such as nonlinear absorption (β), nonlinear refractive index (n 2 ) and nonlinear susceptibility (χ 3 ) are calculated for this sample by using Z-scan technique. CdS/PVA samples show the two photon absorption mechanism. The third order nonlinear susceptibility is calculated from n 2 and β and is found to be of the order of 10 −7 – 10 −8 m 2 /V 2 . The larger value of third order nonlinear susceptibility is due to dielectric and quantum confinement effect

  18. Heteroepitaxy of orientation-patterned nonlinear optical materials (United States)

    Tassev, Vladimir L.; Vangala, Shivashankar R.; Peterson, Rita D.; Snure, Michael


    We report some recent results on thick heteroepitaxial growth of GaP on GaAs substrates and on orientation-patterned (OP) GaAs templates conducted in a hot-wall horizontal quartz reactor for Hydride Vapor Phase Epitaxy. The growths on the plain substrates resulted in up to 500 μm thick GaP with smooth surface morphology (RMS optical microscopy, transmission optical measurements, transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy. The focus was predominantly on the interface and, more precisely, on what influence the pre-growth surface treatment of the substrate has on the initial and the following stages of growth, as well on the mechanisms of the strain relaxation from the lattice and thermal mismatch between layer and substrate. The efforts to accommodate the growing film to the foreign substrate by engineering an intermediate buffer layer were extended to thick growths of GaAsxP1-x ternary with the idea to combine in one material the best of the nonlinear properties of GaP and GaAs that are strictly relevant to the pursued applications.

  19. Geometric optimisation of an accurate cosine correcting optic fibre coupler for solar spectral measurement (United States)

    Cahuantzi, Roberto; Buckley, Alastair


    Making accurate and reliable measurements of solar irradiance is important for understanding performance in the photovoltaic energy sector. In this paper, we present design details and performance of a number of fibre optic couplers for use in irradiance measurement systems employing remote light sensors applicable for either spectrally resolved or broadband measurement. The angular and spectral characteristics of different coupler designs are characterised and compared with existing state-of-the-art commercial technology. The new coupler designs are fabricated from polytetrafluorethylene (PTFE) rods and operate through forward scattering of incident sunlight on the front surfaces of the structure into an optic fibre located in a cavity to the rear of the structure. The PTFE couplers exhibit up to 4.8% variation in scattered transmission intensity between 425 nm and 700 nm and show minimal specular reflection, making the designs accurate and reliable over the visible region. Through careful geometric optimization near perfect cosine dependence on the angular response of the coupler can be achieved. The PTFE designs represent a significant improvement over the state of the art with less than 0.01% error compared with ideal cosine response for angles of incidence up to 50°.

  20. New Architecture of Optical Interconnect for High-Speed Optical Computerized Data Networks (Nonlinear Response

    Directory of Open Access Journals (Sweden)

    El-Sayed A. El-Badawy


    Full Text Available Although research into the use of optics in computers has increased in the last and current decades, the fact remains that electronics is still superior to optics in almost every way. Research into the use of optics at this stage mirrors the research into electronics after the 2nd World War. The advantages of using fiber optics over wiring are the same as the argument for using optics over electronics in computers. Even through totally optical computers are now a reality, computers that combine both electronics and optics, electro-optic hybrids, have been in use for some time. In the present paper, architecture of optical interconnect is built up on the bases of four Vertical-Cavity Surface- Emitting Laser Diodes (VCSELD and two optical links where thermal effects of both the diodes and the links are included. Nonlinear relations are correlated to investigate the power-current and the voltage-current dependences of the four devices. The good performance (high speed of the interconnect is deeply and parametrically investigated under wide ranges of the affecting parameters. The high speed performance is processed through three different effects, namely the device 3-dB bandwidth, the link dispersion characteristics, and the transmitted bit rate (soliton. Eight combinations are investigated; each possesses its own characteristics. The best architecture is the one composed of VCSELD that operates at 850 nm and the silica fiber whatever the operating set of causes. This combination possesses the largest device 3-dB bandwidth, the largest link bandwidth and the largest soliton transmitted bit rate. The increase of the ambient temperature reduces the high-speed performance of the interconnect

  1. A geometric view on Pearson’s correlation coefficient and a generalization of it to non-linear dependencies

    Directory of Open Access Journals (Sweden)

    Priyantha Wijayatunga


    Full Text Available Measuring strength or degree of statistical dependence between two random variables is a common problem in many domains. Pearson’s correlation coefficient ρ is an accurate measure of linear dependence. We show that ρ is a normalized, Euclidean type distance between joint probability distribution of the two random variables and that when their independence is assumed while keeping their marginal distributions. And the normalizing constant is the geometric mean of two maximal distances; each between the joint probability distribution when the full linear dependence is assumed while preserving respective marginal distribution and that when the independence is assumed. Usage of it is restricted to linear dependence because it is based on Euclidean type distances that are generally not metrics and considered full dependence is linear. Therefore, we argue that if a suitable distance metric is used while considering all possible maximal dependences then it can measure any non-linear dependence. But then, one must define all the full dependences. Hellinger distance that is a metric can be used as the distance measure between probability distributions and obtain a generalization of ρ for the discrete case.

  2. Nonlinear Geometric Warping of the Mask Image: A New Method for Reducing Misregistration Artifacts in Digital Subtraction Angiography

    International Nuclear Information System (INIS)

    Hayashi, Nobushige; Sakai, Toyohiko; Kitagawa, Manabu; Inagaki, Rika; Sadato, Norihiro; Ishii, Yasushi; Nishimoto, Yasuhiro; Tanaka, Masato; Fukushima, Tetsuya; Komuro, Hiroyuki; Ogura, Hisakazu; Kobayashi, Hidenori; Kubota, Toshihiko


    Purpose: Misregistration artifact is the major cause of image degradation in digital subtraction angiography (DSA). The purpose of this study was to evaluate the efficacy of a newly developed nonlinear geometric warping method to reduce misregistration artifact in DSA. Methods: The processing of the images was carried out on a workstation with a fully automatic computerized program. After making differential images with a lapracian filter, 49 regions of interest (ROIs) were set in the image to be processed. Each ROI of the live image scanned the corresponding ROI of the mask image searching for the best position to match itself. Each pixel of the mask image was shifted individually following the data calculated from the shifts of the ROIs. Five radiologists compared the images produced by the conventional parallel shift technique and those processed with this new method in 16 series of cerebral DSA. Results: In 14 of 16 series (88%), more radiologists judged the images processed with the new method to be better in quality. Small arteries near the skull base and veins of low density were clearly visualized in the images processed by the new method. Conclusion: This newly proposed method could be a simple and practical way to automatically reduce misregistration artifacts in DSA

  3. Studies on crystal growth, vibrational and optical properties of organic nonlinear optical crystal: p-Aminoazobenzene (United States)

    Eazhilarasi, G.; Nagalakshmi, R.; Krishnakumar, V.


    p-Aminoazobenzene ( p-AAZB), an organic nonlinear optical (NLO) crystal having good optical quality has been grown by slow evaporation solution technique using ethanol as a solvent. Solubility studies were performed at different temperatures. The structural characterization of the grown crystals was carried out by X-ray diffraction. Group theoretical analysis was carried out to calculate the number of modes of vibration. The lowering of the wave numbers of azo group suggests the existence of strong intermolecular N-H⋯H hydrogen bonding. This has been analysed based on the vibrational spectral features. Optical absorption studies show the effective transmission in the entire UV-vis region. The second harmonic generation results show the suitability of this material for NLO applications.

  4. Nonlinear Phase Distortion in a Ti:Sapphire Optical Amplifier for Optical Stochastic Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Andorf, Matthew [NICADD, DeKalb; Lebedev, Valeri [Fermilab; Piot, Philippe [NICADD, DeKalb; Ruan, Jinhao [Fermilab


    Optical Stochastic Cooling (OSC) has been considered for future high-luminosity colliders as it offers much faster cooling time in comparison to the micro-wave stochastic cooling. The OSC technique relies on collecting and amplifying a broadband optical signal from a pickup undulator and feeding the amplified signal back to the beam. It creates a corrective kick in a kicker undulator. Owing to its superb gain qualities and broadband amplification features, Titanium:Sapphire medium has been considered as a gain medium for the optical amplifier (OA) needed in the OSC*. A limiting factor for any OA used in OSC is the possibility of nonlinear phase distortions. In this paper we experimentally measure phase distortions by inserting a single-pass OA into one leg of a Mach-Zehnder interferometer. The measurement results are used to estimate the reduction of the corrective kick a particle would receive due to these phase distortions in the kicker undulator.

  5. Third order nonlinear optical properties and optical limiting behavior of alkali metal complexes of p-nitrophenol (United States)

    Thangaraj, M.; Vinitha, G.; Sabari Girisun, T. C.; Anandan, P.; Ravi, G.


    Optical nonlinearity of metal complexes of p-nitrophenolate (M=Li, Na and K) in ethanol is studied by using a continuous wave (cw) diode pumped Nd:YAG laser (532 nm, 50 mW). The predominant mechanism of observed nonlinearity is thermal in origin. The nonlinear refractive index and the nonlinear absorption coefficient of the samples were found to be in the order of 10-8 cm2/W and 10-3 cm/W respectively. Magnitude of third-order optical parameters varies according to the choice of alkali metal chosen for metal complex formation of p-nitrophenolate. The third-order nonlinear susceptibility was found to be in the order of 10-6 esu. The observed saturable absorption and the self-defocusing effect were used to demonstrate the optical limiting action at 532 nm by using the same cw laser beam.

  6. Characterization of the third-order optical nonlinearity spectrum of barium borate glasses (United States)

    Santos, S. N. C.; Almeida, J. M. P.; Paula, K. T.; Tomazio, N. B.; Mastelaro, V. R.; Mendonça, C. R.


    Borate glasses have proven to be an important material for applications ranging from radiation dosimetry to nonlinear optics. In particular, B2O3-BaO based glasses are attractive to frequency generation since their barium metaborate phase (β-BaB2O4 or β-BBO) may be crystallized under proper heat treatment. Despite the vast literature covering their linear and second-order optical nonlinear properties, their third-order nonlinearities remain overlooked. This paper thus reports a study on the nonlinear refraction (n2) of BBO and BBS-DyEu glasses through femtosecond Z-scan technique. The results were modeled using the BGO approach, which showed that oxygen ions are playing a role in the nonlinear optical properties of the glasses studied here. In addition, the barium borate glasses containing rare-earths ions were found to exhibit larger nonlinearities, which is in agreement with previous studies.

  7. Synthesis of nanocomposites based on carbon nanotube/smart copolymer with nonlinear optical properties (United States)

    Sousani, Abbas; Motiei, Hamideh; Najafimoghadam, Peyman; Hasanzade, Reza


    In this study new nanocompoites based on polyglycidylmethacrylate grafted 4-[(4-methoxyphenyl) diazenyl] phenol (Azo-PGMA) and Carboxylicacid functionalized multi-walled carbon nanotubes (MWCNT-COOH) were prepared. The nanocomposites structure was characterized by FT-IR, TGA and SEM. The Z-scan technique was applied for measuring the nonlinear parameters of nanocomposites. The samples after solving in AWM solution (equal ratio of acetone, deionized water and methanol) were investigated by using closed aperture Z-scan technique and a diode-pumped laser at the line 532 nm. All the nonlinear refractive index of the samples at three concentrations of carbon nanotubes in three different intensities of the laser beam were investigated and the nonlinear optical response of them are compared under the same condition. Because of high order of nonlinear refractive coefficient and good nonlinearity, these compounds are suitable candidate for optical switching, optical limiting and electro-optical devices.

  8. Performance emulation and parameter estimation for nonlinear fibre-optic links

    DEFF Research Database (Denmark)

    Piels, Molly; Porto da Silva, Edson; Zibar, Darko


    Fibre-optic communication systems, especially when operating in the nonlinear regime, generally do not perform exactly as theory would predict. A number of methods for data-based evaluation of nonlinear fibre-optic link parameters, both for accurate performance emulation and optimization, are rev......Fibre-optic communication systems, especially when operating in the nonlinear regime, generally do not perform exactly as theory would predict. A number of methods for data-based evaluation of nonlinear fibre-optic link parameters, both for accurate performance emulation and optimization......, are reviewed. In particular, single-step nonlinear impairment based on the Gaussian mixture model, adaptive digital backpropagation, and extension to higher-dimensional spaces using Monte Carlo Markov chains are discussed....

  9. Nonlinear optical properties of Cu nanocluster composite fabricated by 180 keV ion implantation (United States)

    Wang, Y. H.; Wang, Y. M.; Lu, J. D.; Ji, L. L.; Zang, R. G.; Wang, R. W.


    Metal nanocluster composite glass prepared by 180 keV Cu ions into silica with dose of 5×10 16 ions/cm 2 has been studied. The microstructural properties of the nanoclusters has been verified by optical absorption spectra and transmission electron microscopy (TEM). Third-order nonlinear optical properties of the nanoclusters were measured at 1064 and 532 nm excitations using Z-scan technique. The nonlinear refraction index, nonlinear absorption coefficient, and the real and imaginary parts of the third-order nonlinear susceptibility were deduced. Results of the investigation of nonlinear refraction by the off-axis Z-scan configuration were presented and the mechanisms responsible for the nonlinear response were discussed. Third-order nonlinear susceptibility χ(3) of this kind of sample was determined to be 8.7×10 -8 esu at 532 nm and 6.0×10 -8 esu at 1064 nm, respectively.

  10. Creating large second-order optical nonlinearity in optical waveguides written by femtosecond laser pulses in boro-aluminosilicate glass (United States)

    An, Hong-Lin; Arriola, Alexander; Gross, Simon; Fuerbach, Alexander; Withford, Michael J.; Fleming, Simon


    The thermal poling technique was applied to optical waveguides embedded in a commercial boro-aluminosilicate glass, resulting in high levels of induced second-order optical nonlinearity. The waveguides were fabricated using the femtosecond laser direct-write technique, and thermally poled samples were characterized with second harmonic optical microscopy to reveal the distribution profile of the induced nonlinearity. It was found that, in contrast to fused silica, the presence of waveguides in boro-aluminosilicate glass led to an enhancement of the creation of the second-order nonlinearity, which is larger in the laser written waveguiding regions when compared to the un-modified substrate. The magnitude of the nonlinear coefficient d33 achieved in the core of the laser-written waveguides, up to 0.2 pm/V, was comparable to that in thermally poled fused silica, enabling the realization of compact integrated electro-optic devices in boro-aluminosilicate glasses.

  11. 2D wave-front shaping in optical superlattices using nonlinear volume holography. (United States)

    Yang, Bo; Hong, Xu-Hao; Lu, Rong-Er; Yue, Yang-Yang; Zhang, Chao; Qin, Yi-Qiang; Zhu, Yong-Yuan


    Nonlinear volume holography is employed to realize arbitrary wave-front shaping during nonlinear processes with properly designed 2D optical superlattices. The concept of a nonlinear polarization wave in nonlinear volume holography is investigated. The holographic imaging of irregular patterns was performed using 2D LiTaO3 crystals with fundamental wave propagating along the spontaneous polarization direction, and the results agree well with the theoretical predictions. This Letter not only extends the application area of optical superlattices, but also offers an efficient method for wave-front shaping technology.


    Directory of Open Access Journals (Sweden)

    Hanna Bordyuh


    Full Text Available In the present work we analyze the characteristics of holographic grating recording and consider a mechanism of optical nonlinearity in the lyotropic liquid crystal (LLC — viologen samples. Taking into account structural and electrooptical properties of the admixture molecules it is possible to suggest that the recording is realized due to the change of polarizability of π-electron system of coloured viologen derivatives under the action of laser radiation. The main nonlinear optical parameters such as nonlinear refraction coefficient n2, cubic nonlinear susceptibility χ(3, and hyperpolarizability γ were calculated.

  13. Nonlinear optical response of planar and spherical CdSe nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Selyukov, A. S., E-mail:; Isaev, A. A.; Vitukhnovsky, A. G. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Litvak, V. L. [Moscow Institute of Physics and Technology (State University) (Russian Federation); Katsaba, A. V. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Korshunov, V. M. [Bauman Moscow State Technical University (Russian Federation); Vasiliev, R. B. [Moscow State University (Russian Federation)


    The nonlinear optical response of a colloidal solution of planar CdSe semiconductor nanocrystals (nanoplatelets) is studied for the first time. The nonlinear optical response of these nanoparticles is compared to that of spherical CdSe nanocrystals (quantum dots). The photoinduced nonlinearity is attributed to the optical generation of long-lived charge carriers in the nanoobjects under study. It is shown that, upon the exposure of a cell with the solution of nanoparticles to focused continuous-wave (cw) laser radiation with a wavelength of 473 nm, the nonlinear optical responses of CdSe nanoplatelets and quantum dots are somewhat different at identical optical densities at the above-indicated wavelength. The differences are supposedly associated with a higher diffusion rate of spherical nanoparticles in the solution because of their smaller size compared to that of nanoplatelets.

  14. Third-order nonlinear optical studies of anthraquinone dyes using a CW He–Ne laser

    International Nuclear Information System (INIS)

    Pramodini, S; Poornesh, P


    We present investigations on the third-order optical nonlinearity and optical power limiting of anthraquinone dyes. Z-scan measurements were performed using a continuous wave He–Ne laser at 633 nm wavelength as an excitation source. The nonlinear refraction studies exhibited self-defocusing behavior of the dyes. The nonlinear absorption in the dyes was dominated by a reverse saturable absorption process. Self-diffraction ring patterns were observed due to the change in refractive index and thermal lensing. Increase of the electron donating ability of the substituents resulted in enhanced values of the nonlinear optical parameters, establishing the structure–property relationship. The optical limiting study revealed that the dyes possess a lower limiting threshold and clamping level which is very important for eye and sensor protection. Hence, the dyes investigated here emerge as promising candidates for future opto-electronic and photonic device applications such as optical power limiters. (paper)

  15. Third-order nonlinear optical studies of anthraquinone dyes using a CW He-Ne laser (United States)

    Pramodini, S.; Poornesh, P.


    We present investigations on the third-order optical nonlinearity and optical power limiting of anthraquinone dyes. Z-scan measurements were performed using a continuous wave He-Ne laser at 633 nm wavelength as an excitation source. The nonlinear refraction studies exhibited self-defocusing behavior of the dyes. The nonlinear absorption in the dyes was dominated by a reverse saturable absorption process. Self-diffraction ring patterns were observed due to the change in refractive index and thermal lensing. Increase of the electron donating ability of the substituents resulted in enhanced values of the nonlinear optical parameters, establishing the structure-property relationship. The optical limiting study revealed that the dyes possess a lower limiting threshold and clamping level which is very important for eye and sensor protection. Hence, the dyes investigated here emerge as promising candidates for future opto-electronic and photonic device applications such as optical power limiters.

  16. Participation of the Third Order Optical Nonlinearities in Nanostructured Silver Doped Zinc Oxide Thin Solid Films

    Directory of Open Access Journals (Sweden)

    C. Torres-Torres


    Full Text Available We report the transmittance modulation of optical signals in a nanocomposite integrated by two different silver doped zinc oxide thin solid films. An ultrasonic spray pyrolysis approach was employed for the preparation of the samples. Measurements of the third-order nonlinear optical response at a nonresonant 532 nm wavelength of excitation were performed using a vectorial two-wave mixing. It seems that the separated contribution of the optical nonlinearity associated with each film noticeable differs in the resulting nonlinear effects with respect to the additive response exhibited by the bilayer system. An enhancement of the optical Kerr nonlinearity is predicted for prime number arrays of the studied nanoclusters in a two-wave interaction. We consider that the nanostructured morphology of the thin solid films originates a strong modification of the third-order optical phenomena exhibited by multilayer films based on zinc oxide.

  17. All-optical signal processing in quadratic nonlinear materials

    DEFF Research Database (Denmark)

    Johansen, Steffen Kjær


    and the SH. Via quasi-phase-matching (QPM) the phase mismatch and hence the nonlinearity is eÙectively brought under control through periodic sign reversal of the nonlinearity. On theaverage QPM changes the quadratic nonlinearity and induces new cubic nonlinearities in the system. The engineering...... of materials with a second order nonlinearity, the so-called X(2) materials, is faster and stronger than that of more conventional materials with a cubic nonlinearity. The X(2) materials support spatial solitons consisting of two coupled components, the fundamental wave (FW) and its second harmonic (SH...... are dedicated to this part of the research. In chapter 4 the generality of the theoretical approach is emphasised with the derivation and verification of equivalent tools for media with a saturable nonlinearity. The strength of the X(2) nonlinearity strongly depends on the phase mismatch between the FW...


    Directory of Open Access Journals (Sweden)

    M. Wang


    Full Text Available The GaoFen-4 (GF-4 remote sensing satellite is China’s first civilian high-resolution geostationary optical satellite, which has been launched at the end of December 2015. To guarantee the geometric quality of imagery, this paper presents an on-orbit geometric calibration method for the area-array camera of GF-4. Firstly, we introduce the imaging features of area-array camera of GF-4 and construct a rigorous imaging model based on the analysis of the major error sources from three aspects: attitude measurement error, orbit measurement error and camera distortion. Secondly, we construct an on-orbit geometric calibration model by selecting and optimizing parameters of the rigorous geometric imaging model. On this basis, the calibration parameters are divided into two groups: external and internal calibration parameters. The external parameters are installation angles between the area-array camera and the star tracker, and we propose a two-dimensional direction angle model as internal parameters to describe the distortion of the areaarray camera. Thirdly, we propose a stepwise parameters estimation method that external parameters are estimated firstly, then internal parameters are estimated based on the generalized camera frame determined by external parameters. Experiments based on the real data of GF-4 shows that after on-orbit geometric calibration, the geometric accuracy of the images without ground control points is significantly improved.

  19. Illusions in the spatial sense of the eye: geometrical-optical illusions and the neural representation of space. (United States)

    Westheimer, Gerald


    Differences between the geometrical properties of simple configurations and their visual percept are called geometrical-optical illusions. They can be differentiated from illusions in the brightness or color domains, from ambiguous figures and impossible objects, from trompe l'oeil and perspective drawing with perfectly valid views, and from illusory contours. They were discovered independently by several scientists in a short time span in the 1850's. The clear distinction between object and visual space that they imply allows the question to be raised whether the transformation between the two spaces can be productively investigated in terms of differential geometry and metrical properties. Perceptual insight and psychophysical research prepares the ground for investigation of the neural representation of space but, because visual attributes are processed separately in parallel, one looks in vain for a neural map that is isomorphic with object space or even with individual forms it contains. Geometrical-optical illusions help reveal parsing rules for sensory signals by showing how conflicts are resolved when there is mismatch in the output of the processing modules for various primitives as a perceptual pattern's unitary structure is assembled. They point to a hierarchical ordering of spatial primitives: cardinal directions and explicit contours predominate over oblique orientation and implicit contours (Poggendorff illusion); rectilinearity yields to continuity (Hering illusion), point position and line length to contour orientation (Ponzo). Hence the geometrical-optical illusions show promise as analytical tools in unraveling neural processing in vision.

  20. Design considerations for multi component molecular-polymeric nonlinear optical materials

    Energy Technology Data Exchange (ETDEWEB)

    Singer, K.D. (Case Western Reserve Univ., Cleveland, OH (USA). Dept. of Physics); Kuzyk, M.G. (Washington State Univ., Pullman, WA (USA). Dept. of Physics); Fang, T.; Holland, W.R. (AT and T Bell Labs., Princeton, NJ (USA)); Cahill, P.A. (Sandia National Labs., Albuquerque, NM (USA))


    We review our work on multi component polymeric nonlinear optical materials. These materials consist of nonlinear optical molecules incorporated in a polymeric host. A cross-linked triazine polymer incorporating a dicyanovinyl terminated azo dye was found to be relatively stable at 85{degree} and posses an electro-optic coefficient of 11pm/V. We have also observed the zero dispersion condition in a new anomalous dispersion dye for phase matched second harmonic generation, and expect efficient conversion to the blue. A squarylium dye, ISQ, has been found to posses a large third order nonlinearity, and may display two-level behavior. 24 refs., 11 figs.

  1. Multimodal nonlinear optical microscopy used to discriminate human colon cancer (United States)

    Adur, Javier; Pelegati, Vitor B.; Bianchi, Mariana; de Thomaz, André A.; Baratti, Mariana O.; Carvalho, Hernandes F.; Casco, Víctor H.; Cesar, Carlos L.


    Colon cancer is one of the most diffused cancers in the Western World, ranking third worldwide in frequency of incidence after lung and breast cancers. Even if it is curable when detected and treated early, a more accurate premature diagnosis would be a suitable aim for both cancer prognostic and treatment. Combined multimodal nonlinear optical (NLO) microscopies, such as two-photon excitation fluorescence (TPEF), second-harmonic generation (SHG), third harmonic generation (THG), and fluorescence lifetime imaging microscopy (FLIM) can be used to detect morphological and metabolic changes associated with stroma and epithelial transformation in colon cancer disease. NLO microscopes provide complementary information about tissue microstructure, showing distinctive patterns between normal and malignant human colonic mucosa. Using a set of scoring methods significant differences both in the content, distribution and organization of stroma collagen fibrils, and lifetime components of NADH and FAD cofactors of human colon mucosa biopsies were found. Our results provide a framework for using NLO techniques as a clinical diagnostic tool for human colon cancer, and also suggest that the SHG and FLIM metrics could be applied to other intestinal disorders, which are characterized by abnormal cell proliferation and collagen assembly.

  2. Nonlinear optical properties of Sn+ ion-implanted silica glass

    International Nuclear Information System (INIS)

    Takeda, Y.; Hioki, T.; Motohiro, T.; Noda, S.; Kurauchi, T.


    The absolute value of the third-order nonlinear optical susceptibility, vertical stroke χ (3) vertical stroke , of Sn + ion-implanted silica glass was found to be similar 10 -6 esu. This value is as large as those reported for semiconductor-doped glasses. Silica glass substrates were implanted with Sn + ions at an acceleration energy of 400 keV to a dose of 2x10 17 ions/cm 2 at room temperature. Metallic Sn microcrystallites of 4-20 nm in diameter were found to be embedded in the silica glass matrix. The average volume fraction of the Sn microcrystallites was evaluated to be 28%. vertical stroke χ (3) vertical stroke and the imaginary part of the dielectric function, Im ε, had peaks at the same wavelength of 500 nm owing to surface plasmon resonance. The peak width of vertical stroke χ (3) vertical stroke was nearly half of that of Im ε, which can be explained by an effective medium theory. ((orig.))

  3. Analysis of nonlinear optical properties in donor–acceptor materials

    International Nuclear Information System (INIS)

    Day, Paul N.; Pachter, Ruth; Nguyen, Kiet A.


    Time-dependent density functional theory has been used to calculate nonlinear optical (NLO) properties, including the first and second hyperpolarizabilities as well as the two-photon absorption cross-section, for the donor-acceptor molecules p-nitroaniline and dimethylamino nitrostilbene, and for respective materials attached to a gold dimer. The CAMB3LYP, B3LYP, PBE0, and PBE exchange-correlation functionals all had fair but variable performance when compared to higher-level theory and to experiment. The CAMB3LYP functional had the best performance on these compounds of the functionals tested. However, our comprehensive analysis has shown that quantitative prediction of hyperpolarizabilities is still a challenge, hampered by inadequate functionals, basis sets, and solvation models, requiring further experimental characterization. Attachment of the Au 2 S group to molecules already known for their relatively large NLO properties was found to further enhance the response. While our calculations show a modest enhancement for the first hyperpolarizability, the enhancement of the second hyperpolarizability is predicted to be more than an order of magnitude

  4. Automatic Geometric Processing for Very High Resolution Optical Satellite Data Based on Vector Roads and Orthophotos

    Directory of Open Access Journals (Sweden)

    Peter Pehani


    Full Text Available In response to the increasing need for fast satellite image processing SPACE-SI developed STORM—a fully automatic image processing chain that performs all processing steps from the input optical images to web-delivered map-ready products for various sensors. This paper focuses on the automatic geometric corrections module and its adaptation to very high resolution (VHR multispectral images. In the automatic ground control points (GCPs extraction sub-module a two-step algorithm that utilizes vector roads as a reference layer and delivers GCPs for high resolution RapidEye images with near pixel accuracy was initially implemented. Super-fine positioning of individual GCPs onto an aerial orthophoto was introduced for VHR images. The enhanced algorithm is capable of achieving accuracy of approximately 1.5 pixels on WorldView-2 data. In the case of RapidEye images the accuracies of the physical sensor model reach sub-pixel values at independent check points. When compared to the reference national aerial orthophoto the accuracies of WorldView-2 orthoimages automatically produced with the rational function model reach near-pixel values. On a heterogeneous set of 41 RapidEye images the rate of automatic processing reached 97.6%. Image processing times remained under one hour for standard-size images of both sensor types.

  5. Inexpensive demonstration set for teaching geometrical optics made by 3D printer (United States)

    Havlíček, Karel; Ryston, Matěj


    Good sets for teaching geometric optics are relatively expensive to buy and difficult to make on your own, which often forces teachers to use less than ideal instruments and methods. This is a great shame, since this is a visually appealing topic that can motivate students. For this reason, we have designed a set that is relatively cheap, easy to use and can therefore (in some cases) remedy this situation. Our set is manufactured using 3D printing technology, which limits its users to those that have access to it; however, 3D printing technology is becoming more and more accessible every day (even in schools). On the other hand, 3D printing allows us to let the machines do the majority of the manufacturing work, making the process of building the set almost as simple as ‘download and press print’. This article presents this set, what it consists of, how it is done and where can you find all the necessary files and instructions.

  6. Non-geometrical optics investigation of mode conversion in weakly relativistic inhomogeneous plasmas

    International Nuclear Information System (INIS)

    Imre, K.


    Electron cyclotron resonance heating of plasmas by waves incident to the fundamental and second harmonic layer is investigated. When the wave propagation is nearly perpendicular to the equilibrium field in a weakly inhomogeneous plasma the standard geometrical optics breaks down and the relativistic corrections become significant at the resonance layer. Unlike the previous studies of this problem, the governing equations are derived from the linearized relativistic Vlasov equation coupled with Maxwell's equations, rather than using the uniform field dispersion relation to construct equations by replacing the refractive index by some spatial differential operations. We employ a boundary layer analysis at the resonance region and match the inner and outer solutions in the usual manner. We obtain not only the full wave solution of the problem, but also the set of physical parameters and their ranges in which the analysis is valid. Although we obtain analytic results for the asymptotic solutions, our analysis usually requires a numerical procedure when the relativistic and/or nonzero parallel refractive index are included

  7. Studies on third-order nonlinear optical properties of chalcone derivatives in polymer host (United States)

    Shettigar, Seetharam; Umesh, G.; Chandrasekharan, K.; Sarojini, B. K.; Narayana, B.


    In this paper we present the experimental study of the third-order nonlinear optical properties of two chalcone derivatives, viz., 1-(4-methoxyphenyl)-3-(4-butyloxyphenyl)-prop-2-en-1-one and 1-(4-methoxyphenyl)-3-(4-propyloxyphenyl)-prop-2-en-1-one in PMMA host, with the prospective of reaching a compromise between good processability and high nonlinear optical properties. The nonlinear optical properties have been investigated by Z-scan technique using 7 ns laser pulses at 532 nm. The nonlinear refractive index, nonlinear absorption coefficient, magnitude of third-order susceptibility and the coupling factor have been determined. The values obtained are of the order of 10 -14 cm 2/W, 1 cm/GW, 10 -13 esu and 0.2, respectively. The molecular second hyperpolarizability for the chalcone derivatives in polymer is of the order of 10 -31 esu. Different guest/host concentrations have also been studied. The results suggest that the nonlinear properties of the chalcones have been improved when they are used as dopants in polymer matrix. The nonlinear parameters obtained are comparable with the reported values of II-VI compound semiconductors. Hence, these chalcons are a promising class of nonlinear optical dopant materials for optical device applications.

  8. Electron transport and nonlinear optical properties of substituted aryldimesityl boranes: a DFT study.

    Directory of Open Access Journals (Sweden)

    Altaf Hussain Pandith

    Full Text Available A comprehensive theoretical study was carried out on a series of aryldimesityl borane (DMB derivatives using Density Functional theory. Optimized geometries and electronic parameters like electron affinity, reorganization energy, frontiers molecular contours, polarizability and hyperpolarizability have been calculated by employing B3PW91/6-311++G (d, p level of theory. Our results show that the Hammett function and geometrical parameters correlates well with the reorganization energies and hyperpolarizability for the series of DMB derivatives studied in this work. The orbital energy study reveals that the electron releasing substituents increase the LUMO energies and electron withdrawing substituents decrease the LUMO energies, reflecting the electron transport character of aryldimesityl borane derivatives. From frontier molecular orbitals diagram it is evident that mesityl rings act as the donor, while the phenylene and Boron atom appear as acceptors in these systems. The calculated hyperpolarizability of secondary amine derivative of DMB is 40 times higher than DMB (1. The electronic excitation contributions to the hyperpolarizability studied by using TDDFT calculation shows that hyperpolarizability correlates well with dipole moment in ground and excited state and excitation energy in terms of the two-level model. Thus the results of these calculations can be helpful in designing the DMB derivatives for efficient electron transport and nonlinear optical material by appropriate substitution with electron releasing or withdrawing substituents on phenyl ring of DMB system.

  9. Nonlinear optical properties measurement of polypyrrole -carbon nanotubes prepared by an electrochemical polymerization method

    Directory of Open Access Journals (Sweden)



    Full Text Available In this work, the optical properties dependence of Multi-Walled Carbon Nanotubes (MWNT on concentration was discussed. MWNT samples were prepared in polypyrrole by an electrochemical polymerization of monomers, in the presence of different concentrations of MWNTs, using Sodium Dodecyl-Benzen-Sulfonate (SDBS as surfactant at room temperature. The nonlinear refractive and nonlinear absorbtion indices were measured using a low power CW laser beam operated at 532 nm using z-scan method. The results show that nonlinear refractive and nonlinear absorbtion indices tend to be increased with increasing the concentration of carbon nanotubes. Optical properties of  carbone nanotubes indicate that they are good candidates for nonlinear optical devices

  10. Nonlinear optical properties of Cu nanoclusters by ion implantation in silicate glass (United States)

    Wang, Y. H.; Wang, Y. M.; Lu, J. D.; Ji, L. L.; Zang, R. G.; Wang, R. W.


    Metal nanocluster composite glass prepared by 180 keV Cu ions into silica with dose of 1 × 10 17 ions/cm 2 has been studied. The microstructural properties of the nanoclusters were analysed by optical absorption spectra and transmission electron microscopy (TEM). Third-order nonlinear optical properties of the nanoclusters were measured at 1064 nm and 532 nm excitations using Z-scan technique. The nonlinear refraction index, nonlinear absorption coefficient, and the real and imaginary parts of the third-order nonlinear susceptibility were deduced. The mechanisms responsible for the nonlinear response were discussed. Absolute third-order nonlinear susceptibility χ of this kind of sample was determined to be 2.1 × 10 -7 esu at 532 nm and 1.2 × 10 -7 esu at 1064 nm, respectively.

  11. Nonlinear optical and optoelectronic studies of topological insulator surfaces (United States)

    McIver, James W.

    Since their experimental discovery in 2008, topological insulators have been catapulted to the forefront of condensed matter physics research owing to their potential to realize both exciting new technologies as well as novel electronic phases that are inaccessible in any other material class. Their exotic properties arise from a rare quantum organization of its electrons called "topological order,'' which evades the conventional broken symmetry based-classification scheme used to categorize nearly every other state of ordered matter. Instead, topologically ordered phases are classified by topological invariants, which characterize the phase of an electron's wavefunction as it moves through momentum space. When a topologically ordered phase is interfaced with an ordinary phase, such as the vacuum, a novel metallic state appears at their shared boundary. In topological insulators, this results in the formation of a two-dimensional metallic state that spans all of its surfaces. The surface state electronic spectrum is characterized by a single linearly dispersing and helically spin-polarized Dirac cone that is robust against disorder. The helical nature of the surface Dirac cone is highly novel because the Dirac electrons carry a net magnetic moment and are capable of transporting 100% spin-polarized electrical currents, which are the long-sought electronic properties needed for many spin-based electronic applications. However, owing to the small bulk band gap and intrinsic electronic doping inherent to these materials, isolating the surface electronic response from the bulk has proven to be a major experimental obstacle. In this thesis, we demonstrate the means by which light can be used to isolate and study the surface electronic response of topological insulators using optoelectronic and nonlinear optical techniques. In chapter 1, we overview the physics of topological order and topological insulators. In chapter 2, we show how polarized light can be used to

  12. Structural, thermal, optical and nonlinear optical properties of ethylenediaminium picrate single crystals (United States)

    Indumathi, C.; T. C., Sabari Girisun; Anitha, K.; Alfred Cecil Raj, S.


    A new organic optical limiting material, ethylenediaminium picrate (EDAPA) was synthesized through acid base reaction and grown as single crystals by solvent evaporation method. Single crystal XRD analysis showed that EDAPA crystallizes in orthorhombic system with Cmca as space group. The formation of charge transfer complex during the reaction of ethylenediamine and picric acid was strongly evident through the recorded Fourier Transform Infra Red (FTIR), Raman and Nuclear Magnetic Resonance (NMR) spectrum. Thermal (TG-DTA and DSC) curves indicated that the material possesses high thermal stability with decomposition temperature at 243 °C. Optical (UV-Visible-NIR) analysis showed that the grown crystal was found to be transparent in the entire visible and NIR region. Z-scan studies with intense short pulse (532 nm, 5 ns, 100 μJ) excitations, revealed that EDAPA exhibited two photon absorption behaviour and the nonlinear absorption coefficient was found to be two orders of magnitude higher than some of the known optical limiter like Cu nano glasses. EDAPA exhibited a strong optical limiting action with low limiting threshold which make them a potential candidate for eye and photosensitive component protection against intense short pulse lasers.

  13. Computational Study of Chalcopyrite Semiconductors and Their Non-Linear Optical Properties

    National Research Council Canada - National Science Library

    Lambrecht, Walter R


    ... (Including cation antisites, cation and anion vacancies) and CdGeAs2; a study of the feasibility of nonciritical phase matching and associated nonlinear optical parameters in CdSiP2 and CdSIAs2...

  14. An ultra-efficient nonlinear planar integrated platform for optical signal processing and generation

    DEFF Research Database (Denmark)

    Pu, Minhao; Ottaviano, Luisa; Semenova, Elizaveta


    This paper will discuss the recently developed integrated platform: AlGaAs-oninsulator and its broad range of nonlinear applications. Recent demonstrations of broadband optical signal processing and efficient frequency comb generations in this platform will be reviewed....

  15. Self-Assembly of Nanocomposite Nonlinear Optical Materials for Photonic Devices, Phase I (United States)

    National Aeronautics and Space Administration — This program targets the development of new highly anisotropic nonlinear optical nanocomposite materials for NASA and non-NASA applications in advanced photonic and...

  16. Nanosecond nonlinear optical and optical limiting properties of hollow gold nanocages (United States)

    Zheng, Chan; Huang, Jiaxin; Lei, Li; Chen, Wenzhe; Wang, Haiyan; Li, Wei


    Gold nanocages (NCs) were prepared using the galvanic replacement reaction. Transmission electron microscopy images confirmed the porous morphology and completely hollow interior of the gold NCs. The nanosecond nonlinear optical and optical limiting (OL) properties of the NCs were characterized using the open-aperture Z-scan technique with 8-ns laser pulses at 532 nm. The gold NCs exhibited intensity-dependent transformation from saturable absorption to reverse-saturable absorption. The nonlinear absorption coefficient and saturable energy of the NCs were 5 × 10- 12 m/W and 2.5 × 1010 W/m2, respectively. Meanwhile, the gold NCs were found to display strong OL properties towards nanosecond laser pulses. The OL threshold of the gold NCs was lower than that of solid gold nanoparticles and comparable with that of a carbon nanotube suspension. Input fluence and angle-dependent scattering measurements indicated that nonlinear scattering plays an important role in the OL behavior of the gold nanostructures at high laser excitation. The improved OL response in gold NCs was discussed from the viewpoint of structural characteristic. The ultrathin and highly porous walls of the gold NCs can effectively transfer the photon-induced heat to the surrounding solvent, resulting in enhanced OL properties compared with those of solid gold nanoparticles. The intensity-dependent transformation from saturable absorption to reverse-saturable absorption and excellent OL response indicate that the smart gold NCs with ultrathin and highly porous walls can be considered as potential candidate in pulse shaping, passive mode locking, and eye protection against powerful lasers.

  17. Dual-polarization nonlinear Fourier transform-based optical communication system

    DEFF Research Database (Denmark)

    Gaiarin, Simone; Perego, A. M.; da Silva, Edson Porto


    communication could potentially overcome these limitations. It relies on a mathematical technique called “nonlinear Fourier transform (NFT)” to exploit the “hidden” linearity of the nonlinear Schrödinger equation as the master model for signal propagation in an optical fiber. We present here the theoretical...

  18. Sensitive measurement of optical nonlinearity in amorphous chalcogenide materials in nanosecond regime. (United States)

    Rani, Sunita; Mohan, Devendra; Kishore, Nawal; Purnima


    The present work focuses on the nonlinear optical behavior of chalcogenide As(2)S(3) film as well as on bulk material. The thin film of As(2)S(3) grown by thermal evaporation and bulk glass developed by melt-quenched technique has been characterized using nanosecond pulses of Nd:YAG (532 nm) and Nd:YVO(4) (1,064 nm) laser. Using Z-scan technique, the laser induced nonlinear optical parameters viz. nonlinear refractive index (n(2)), nonlinear absorption coefficient (β) and third order nonlinear susceptibility (χ(3)) have been estimated. At 1,064 nm excitation, the materials exhibit stronger nonlinearity as compared to that of 532 nm laser. In case of As(2)S(3) thin film, observed nonlinearity attributes to two-photon absorption. The optical limiting response of chalcogenide film as well as bulk sample has also been reported. The study predicts that the As(2)S(3) thin film is a better optical limiting material than bulk glass due to relatively higher nonlinearity and lower limiting threshold. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Explicit formulation of second and third order optical nonlinearity in the FDTD framework (United States)

    Varin, Charles; Emms, Rhys; Bart, Graeme; Fennel, Thomas; Brabec, Thomas


    The finite-difference time-domain (FDTD) method is a flexible and powerful technique for rigorously solving Maxwell's equations. However, three-dimensional optical nonlinearity in current commercial and research FDTD softwares requires solving iteratively an implicit form of Maxwell's equations over the entire numerical space and at each time step. Reaching numerical convergence demands significant computational resources and practical implementation often requires major modifications to the core FDTD engine. In this paper, we present an explicit method to include second and third order optical nonlinearity in the FDTD framework based on a nonlinear generalization of the Lorentz dispersion model. A formal derivation of the nonlinear Lorentz dispersion equation is equally provided, starting from the quantum mechanical equations describing nonlinear optics in the two-level approximation. With the proposed approach, numerical integration of optical nonlinearity and dispersion in FDTD is intuitive, transparent, and fully explicit. A strong-field formulation is also proposed, which opens an interesting avenue for FDTD-based modelling of the extreme nonlinear optics phenomena involved in laser filamentation and femtosecond micromachining of dielectrics.

  20. Characterization of the bistable wideband optical filter on the basis of nonlinear 2D photonic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Guryev, I. V., E-mail:; Sukhoivanov, I. A., E-mail:; Andrade Lucio, J. A., E-mail:; Manzano, O. Ibarra, E-mail:; Rodriguez, E. Vargaz, E-mail:; Gonzales, D. Claudio, E-mail:; Chavez, R. I. Mata, E-mail:; Gurieva, N. S., E-mail: [University of Guanajuato, Engineering division (Mexico)


    In our work, we investigated the wideband optical filter on the basis of nonlinear photonic crystal. The all-optical flip-flop using ultra-short pulses with duration lower than 200 fs is obtained in such filters. Here we pay special attention to the stability problem of the nonlinear element. To investigate this problem, the temporal response demonstrating the flip-flop have been computed within the certain range of the wavelengths as well as at different input power.

  1. In situ 3D characterization of historical coatings and wood using multimodal nonlinear optical microscopy


    Latour , Gaël; Echard , Jean-Philippe; Didier , Marie; Schanne-Klein , Marie-Claire


    International audience; We demonstrate multimodal nonlinear optical imaging of historical artifacts by combining Second Harmonic Generation (SHG) and Two-Photon Excited Fluorescence (2PEF) microscopies. We first identify the nonlinear optical response of materials commonly encountered in coatings of cultural heritage artifacts by analyzing one- and multi-layered model samples. We observe 2PEF signals from cochineal lake and sandarac and show that pigments and varnish films can be discriminate...

  2. Weak field nonlinear optical response of fermions in Frenkel exciton chains

    International Nuclear Information System (INIS)

    Spano, F.C.


    In this paper, the third order nonlinear optical response of a Frenkel chain composed of N dipole-dipole coupled two-level molecules is reviewed. The fundamantal electronic excitations of such a system are, in fact, fermions, a property which greatly simplifies the eigenspectrum for multiexciton states. The introduction of site disorder does not disrupt the fermion nature and is therefore easily incorporated into a general expression of the third order nonlinear optical susceptibility

  3. Gradiometer Based on Nonlinear Magneto-Optic Rotation, Phase I (United States)

    National Aeronautics and Space Administration — This Phase I SBIR project will demonstrate sensitive measurements of magnetic field gradients by nonlinear atomic spectroscopy. The gradients are determined by...

  4. An application of the method of geometrical optics to the scattering of plane electromagnetic waves off cylindrically confined cold plasmas

    International Nuclear Information System (INIS)

    Kriegsmann, G.A.


    In this paper we apply the method of geometrical optics to study the scattering of plane electromagnetic waves off a cylindrically confined cold plasma. For simplicity, we assume two types of incident polarization. In both cases scalar second order elliptic partial differential equations describe the fields. These problems are studied in the asymptotic limit aω/c→infinity (where a is the radius of the cylinder, ω is the frequency of the incident plane wave, and c is the velocity of light in free space). We furthermore assume a quadratic plasma density. This allows us to calculate explicitly the rays, amplitudes, caustics, and other features which arise in the geometrical optics approach. The assumed density also gives rise to the interesting cutoff and resonance phenomenon. Thus the amplification of the electromagnetic fields is observed. This phenomenon may have applications in laser fusion

  5. Third-order nonlinear optical response of Ag-CdSe/PVA hybrid nanocomposite

    International Nuclear Information System (INIS)

    Tripathi, S.K.; Kaur, Ramneek; Kaur, Jaspreet; Sharma, Mamta


    Hybrid nanocomposites of II-VI semiconductor nanoparticles are gaining great interest in nonlinear optoelectronic devices. Present work includes the characterization of CdSe polymer nanocomposite prepared by chemical in situ technique. From X-ray diffraction, the hexagonal wurtzite structure of nanoparticles has been confirmed with spherical morphology from transmission electron microscopy. Ag-CdSe hybrid polymer nanocomposite has been prepared chemically at different Ag concentrations. The presence of Ag in hybrid nanocomposite has been confirmed with energy-dispersive X-ray spectroscopy. The effect of varying Ag concentration on the linear and nonlinear optical properties of the nanocomposites has been studied. In linear optical parameters, the linear absorption coefficient, refractive index, extinction coefficient and optical conductivity have been calculated. The third-order nonlinear optical properties have been observed with open- and closed-aperture Z-scan technique. The large nonlinear refractive index ∝10 -5 cm 2 /W with self-focusing behaviour is due to the combined effect of quantum confinement and thermo-optical effects. The enhanced nonlinearity with increasing Ag content is due to the surface plasmon resonance, which enhances the local electric field near the nanoparticle surface. Thus, Ag-CdSe hybrid polymer nanocomposite has favourable nonlinear optical properties for various optoelectronic applications. (orig.)

  6. Third-order nonlinear optical response of Ag-CdSe/PVA hybrid nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, S.K.; Kaur, Ramneek; Kaur, Jaspreet; Sharma, Mamta [Panjab University, Department of Physics, Center of Advanced Study in Physics, Chandigarh (India)


    Hybrid nanocomposites of II-VI semiconductor nanoparticles are gaining great interest in nonlinear optoelectronic devices. Present work includes the characterization of CdSe polymer nanocomposite prepared by chemical in situ technique. From X-ray diffraction, the hexagonal wurtzite structure of nanoparticles has been confirmed with spherical morphology from transmission electron microscopy. Ag-CdSe hybrid polymer nanocomposite has been prepared chemically at different Ag concentrations. The presence of Ag in hybrid nanocomposite has been confirmed with energy-dispersive X-ray spectroscopy. The effect of varying Ag concentration on the linear and nonlinear optical properties of the nanocomposites has been studied. In linear optical parameters, the linear absorption coefficient, refractive index, extinction coefficient and optical conductivity have been calculated. The third-order nonlinear optical properties have been observed with open- and closed-aperture Z-scan technique. The large nonlinear refractive index ∝10{sup -5} cm{sup 2}/W with self-focusing behaviour is due to the combined effect of quantum confinement and thermo-optical effects. The enhanced nonlinearity with increasing Ag content is due to the surface plasmon resonance, which enhances the local electric field near the nanoparticle surface. Thus, Ag-CdSe hybrid polymer nanocomposite has favourable nonlinear optical properties for various optoelectronic applications. (orig.)

  7. Statistics of optical and geometrical properties of cirrus cloud over tibetan plateau measured by lidar and radiosonde

    Directory of Open Access Journals (Sweden)

    Dai Guangyao


    Full Text Available Cirrus clouds affect the energy budget and hydrological cycle of the earth’s atmosphere. The Tibetan Plateau (TP plays a significant role in the global and regional climate. Optical and geometrical properties of cirrus clouds in the TP were measured in July-August 2014 by lidar and radiosonde. The statistics and temperature dependences of the corresponding properties are analyzed. The cirrus cloud formations are discussed with respect to temperature deviation and dynamic processes.

  8. Growth and characterization of nonlinear optical single crystals: bis ...

    Indian Academy of Sciences (India)


    telecommunication, optical switching, optical frequency conversion, THz generation, electro-optical and inte- grated optics.1,2 In recent times, polar aromatic organic molecules have received great attention for NLO applica- tions. However, NLO properties of several inorganic crystals such as LiNbO3, GaP have been widely ...

  9. Photoconductivity, photoluminescence and optical Kerr nonlinear effects in zinc oxide films containing chromium nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Torres, C., E-mail: [Seccion de Estudios de Posgrado e Investigacion, ESIME-Z, Instituto Politecnico Nacional, Mexico, DF 07738 (Mexico); Garcia-Cruz, M.L. [Centro de Investigacion en Dispositivos Semiconductores, Benemerita Universidad Autonoma de Puebla, A. P. J-48, Puebla 72570, Mexico (Mexico); Castaneda, L., E-mail: [Instituto de Fisica, Benemerita Universidad Autonoma de Puebla, A. P. J-48, Puebla 72570, Mexico (Mexico); Rangel Rojo, R. [CICESE/Depto. de Optica, A. P. 360, Ensenada, BC 22860 (Mexico); Tamayo-Rivera, L. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Mexico, DF 01000 (Mexico); Maldonado, A. [Depto. de Ing. Electrica, CINVESTAV IPN-SEES, A. P. 14740, Mexico DF 07000 (Mexico); Avendano-Alejo, M., E-mail: [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, A. P. 70-186, 04510, DF (Mexico); and others


    Chromium doped zinc oxide thin solid films were deposited on soda-lime glass substrates. The photoconductivity of the material and its influence on the optical behavior was evaluated. A non-alkoxide sol-gel synthesis approach was used for the preparation of the samples. An enhancement of the photoluminescence response exhibited by the resulting photoconductive films with embedded chromium nanoclusters is presented. The modification in the photoconduction induced by a 445 nm wavelength was measured and then associated with the participation of the optical absorptive response. In order to investigate the third order optical nonlinearities of the samples, a standard time-resolved Optical Kerr Gate configuration with 80 fs pulses at 830 nm was used and a quasi-instantaneous pure electronic nonlinearity without the contribution of nonlinear optical absorption was observed. We estimate that from the inclusion of Cr nanoclusters into the sample results a strong optical Kerr effect originated by quantum confinement. The large photoluminescence response and the important refractive nonlinearity of the photoconductive samples seem to promise potential applications for the development of multifunctional all-optical nanodevices. - Highlights: Black-Right-Pointing-Pointer Enhancement in photoluminescence for chromium doped zinc oxide films is presented. Black-Right-Pointing-Pointer A strong and ultrafast optical Kerr effect seems to result from quantum confinement. Black-Right-Pointing-Pointer Photoconductive properties for optical and optoelectronic functions were observed.

  10. Nonlinear Pulse Shaping in Fibres for Pulse Generation and Optical Processing

    Directory of Open Access Journals (Sweden)

    Sonia Boscolo


    Full Text Available The development of new all-optical technologies for data processing and signal manipulation is a field of growing importance with a strong potential for numerous applications in diverse areas of modern science. Nonlinear phenomena occurring in optical fibres have many attractive features and great, but not yet fully explored, potential in signal processing. Here, we review recent progress on the use of fibre nonlinearities for the generation and shaping of optical pulses and on the applications of advanced pulse shapes in all-optical signal processing. Amongst other topics, we will discuss ultrahigh repetition rate pulse sources, the generation of parabolic shaped pulses in active and passive fibres, the generation of pulses with triangular temporal profiles, and coherent supercontinuum sources. The signal processing applications will span optical regeneration, linear distortion compensation, optical decision at the receiver in optical communication systems, spectral and temporal signal doubling, and frequency conversion.

  11. Second-order nonlinear optical properties of mexylaminotriazine-functionalized glass-forming azobenzene derivatives (United States)

    Umezawa, Hirohito; Jackson, Matthew; Lebel, Olivier; Nunzi, Jean-Michel; Sabat, Ribal Georges


    The second-order nonlinear optical coefficients of thin films of mexylaminotriazine-functionalized azobenzene molecular glass derivatives were measured using second harmonic generation. The thin films were poled using a custom corona poling set-up and the second harmonic light from a pulsed 1064-nm laser was detected. Four out of the six tested compounds showed optical nonlinearity and a maximum coefficient of 75 pm/V was obtained. The time dependence of the nonlinear coefficients was studied under ambient light and under dark; the second harmonic generation intensity stayed constant for thiazole-containing derivatives while a significant decay was measured for the other compounds.

  12. Non-Linear Optical Studies of IR Materials with Infrared Femtosecond Laser (United States)


    AFRL-RD-PS- AFRL-RD-PS- TR-2016-0055 TR-2016-0055 NON-LINEAR OPTICAL STUDIES OF IR MATERIALS WITH INFRARED FEMTOSECOND LASER Enam...TITLE AND SUBTITLE Non-Linear Optical Studies of IR Materials with Infrared Femtosecond Laser 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9451-14-1...femtosecond mid- IR (MIR) pulses from 2 - 4 micron wavelength at a 1 kHz repetition rate were used to explore nonlinear effects into various MIR materials

  13. NLO 󈨞. Nonlinear Optics: Materials, Phenomena and Devices Digest. Internation Meeting on Nonlinear Optics (1st) Held in Kauai, Hawaii on 16-20 July 1990 (United States)


    combination50 with a dynamic grating diffraction modelO . Considering o 0 a polarlsatlon grating on a homoetropic aligned nematlc ’-i 40 filmi the optical...nonlinearities of solutions of chloroaluminumphthalocyanine (CAP) in methanol and a silicon naphthalocyanine (Nc) derivative, SiNc( OSi (hexyl)3)2 or

  14. Optical nonlinearities of excitonic states in atomically thin 2D transition metal dichalcogenides

    Energy Technology Data Exchange (ETDEWEB)

    Soh, Daniel Beom Soo [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Proliferation Signatures Discovery and Exploitation Department


    We calculated the optical nonlinearities of the atomically thin monolayer transition metal dichalcogenide material (particularly MoS2), particularly for those linear and nonlinear transition processes that utilize the bound exciton states. We adopted the bound and the unbound exciton states as the basis for the Hilbert space, and derived all the dynamical density matrices that provides the induced current density, from which the nonlinear susceptibilities can be drawn order-by-order via perturbative calculations. We provide the nonlinear susceptibilities for the linear, the second-harmonic, the third-harmonic, and the kerr-type two-photon processes.

  15. Nonlinear optical studies on 1,3-disubstituent chalcones doped polymer films (United States)

    Poornesh, P.; Shettigar, Seetharam; Umesh, G.; Manjunatha, K. B.; Prakash Kamath, K.; Sarojini, B. K.; Narayana, B.


    We report the measurements of the third-order nonlinear optical properties of recently synthesized and characterized two different 1,3-disubstituent chalcones doped PMMA films, with the prospective of reaching a good compromise between processability and high nonlinear optical properties. The measurements were done using nanosecond Z-scan at 532 nm. The Z-scan spectra reveal a large negative nonlinear refraction coefficient n2 of the order 10 -11 esu and the molecular two photon absorption cross section is 10 -46 cm 4 s/photon. The doped films exhibit good optical power limiting property under nanosecond regime and the two photon absorption (TPA) is the dominating process leading to the nonlinear behavior. The improvement in the nonlinear properties has been observed when methylenedioxy group is replaced by dimethoxy group due to increase in conjugation length. The observed nonlinear parameters of chalcone derivatives doped PMMA film is comparable with stilbazolieum derivatives, a well-known class of optical materials for photonics and biophotonics applications, which suggests that, these moieties have potential for the application of all-optical limiting and switching devices.

  16. Symbolic-computation study of the perturbed nonlinear Schrodinger model in inhomogeneous optical fibers

    International Nuclear Information System (INIS)

    Tian Bo; Gao Yitian


    A realistic, inhomogeneous fiber in the optical communication systems can be described by the perturbed nonlinear Schrodinger model (also named as the normalized nonlinear Schrodinger model with periodically varying coefficients, dispersion managed nonlinear Schrodinger model or nonlinear Schrodinger model with variable coefficients). Hereby, we extend to this model a direct method, perform symbolic computation and obtain two families of the exact, analytic bright-solitonic solutions, with or without the chirp respectively. The parameters addressed include the shape of the bright soliton, soliton amplitude, inverse width of the soliton, chirp, frequency, center of the soliton and center of the phase of the soliton. Of optical and physical interests, we discuss some previously-published special cases of our solutions. Those solutions could help the future studies on the optical communication systems. ms

  17. Substituent Dependence of Third-Order Optical Nonlinearity in Chalcone Derivatives (United States)

    Kiran, Anthony John; Satheesh Rai, Nooji; Chandrasekharan, Keloth; Kalluraya, Balakrishna; Rotermund, Fabian


    The third-order nonlinear optical properties of derivatives of dibenzylideneacetone were investigated using the single beam z-scan technique at 532 nm. A strong dependence of third-order optical nonlinearity on electron donor and acceptor type of substituents was observed. An enhancement in χ(3)-value of one order of magnitude was achieved upon the substitution of strong electron donors compared to that of the molecule substituted with an electron acceptor. The magnitude of nonlinear refractive index of these chalcones is as high as of 10-11 esu. Their nonlinear optical coefficients are larger than those of widely used thiophene oligomers and trans-1-[p-(p-dimethylaminobenzyl-azo)-benzyl]-2-(N-methyl-4-pyridinium)-ethene iodide (DABA-PEI) organic compounds.

  18. Acetylenic dithiafulvene derived donor-pi-acceptor dyads: synthesis, electrochemistry and non-linear optical properties

    DEFF Research Database (Denmark)

    Nielsen, Mogens Brønsted; Petersen, Jan Conrad; Thorup, Niels


    A selection of donor-acceptor chromophores containing the redox-active dithiafulvene unit about acetylenic and aryl scaffolds has been synthesized. The molecules were studied for their optical, redox and structural properties. Moreover, third-order non-linear optical properties were investigated ...


    NARCIS (Netherlands)


    Nonlinear optical susceptibilities provide a convenient means of relating macroscopic optical measurements to microscopic models. The susceptibilities are most useful when the radiation field and the material degrees of freedom are weakly coupled. In the opposite case, the dynamics is interpreted in

  20. Transient Gratings, Four-Wave Mixing and Polariton Effects in Nonlinear Optics

    NARCIS (Netherlands)

    Knoester, Jasper; Mukamel, Shaul


    Nonlinear optical susceptibilities provide a convenient means of relating macroscopic optical measurements to microscopic models. The susceptibilities are most useful when the radiation field and the material degrees of freedom are weakly coupled. In the opposite case, the dynamics is interpreted in

  1. Aggregation induced enhancement of linear and nonlinear optical emission from a hexaphenylene derivative

    NARCIS (Netherlands)

    Duan, Y.; Ju, C.G.; Yang, G.; Fron, E.; Coutino-Gonzalez, E.; Semin, S.V.; Fan, C.C.; Balok, R.S.; Cremers, J.; Tinnemans, P.T.; Feng, Y.Q.; Li, Y.L.; Hofkens, J.; Rowan, A.E.; Rasing, T.H.M.; Xu, J.L.


    The discovery of the phenomenon known as aggregation-induced emission (AIE) has opened the door to a variety of brilliant organic solid-state light-emitting materials. While AIE is well established in linear optics, the development of AIE luminogens (AIEgens) with highly efficient nonlinear optical

  2. Structural, electrical, thermal and optical properties of the nonlinear optical crystal L-Arginine Fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Mohandoss, R.; Dhanuskodi, S. [School of Physics, Bharathidasan University, Tiruchirappalli-620 024 (India); Jayalakshmy, M.S.; Philip, J. [Sophisticated Test and Instrumentation Centre, Cochin University of Science and Technology, Cochin-682 002 (India); Bhagavannarayana, G. [Crystal Growth and Crystallography Section, Materials Characterization Division, National Physical Laboratory, New Delhi-110 012 (India)


    Single crystals of L-Arginine Fluoride (LAF) have been grown by the slow evaporation technique, and the crystalline perfection was studied by HRXRD. Optical absorption studies reveal the lower cut off wavelength (280 nm) and the band gap (5.1 eV). The dielectric constant and dielectric loss have been measured as a function of frequency (42 Hz-5 MHz) and temperature (307-368K) and the activation energy is 77 {mu}eV. The thermal transport properties such as thermal conductivity (0.88 {+-} 0.02 W/mK) and specific heat capacity (482{+-}24 J/kg/K) have been estimated by the photopyroelectric technique. The nonlinear refractive index n{sub 2}, is found to be of the order of 10{sup -13} cm{sup 2}/W by the Z-scan technique. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Geometrical optics in the near field: local plane-interface approach with evanescent waves. (United States)

    Bose, Gaurav; Hyvärinen, Heikki J; Tervo, Jani; Turunen, Jari


    We show that geometrical models may provide useful information on light propagation in wavelength-scale structures even if evanescent fields are present. We apply a so-called local plane-wave and local plane-interface methods to study a geometry that resembles a scanning near-field microscope. We show that fair agreement between the geometrical approach and rigorous electromagnetic theory can be achieved in the case where evanescent waves are required to predict any transmission through the structure.

  4. Structural and nonlinear optical properties of as-grown and annealed metallophthalocyanine thin films

    Energy Technology Data Exchange (ETDEWEB)

    Zawadzka, A., E-mail: [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland); Płóciennik, P.; Strzelecki, J. [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland); Pranaitis, M.; Dabos-Seignon, S.; Sahraoui, B. [LUNAM Université, Université d' Angers, CNRS UMR 6200, Laboratoire MOLTECH-Anjou, 2 bd Lavoisier, 49045 Angers cedex (France)


    The paper presents the Third Harmonic Generation investigation of four metallophtalocyanine (MPc, M = Cu, Co, Mg and Zn) thin films. The investigated films were fabricated by Physical Vapor Deposition in high vacuum onto quartz substrates. MPc thin films were annealed after fabrication in ambient atmosphere for 12 h at the temperature equal to 150 °C or 250 °C. The Third Harmonic Generation spectra were measured to investigate the nonlinear optical properties and their dependence on the structure of the thin film after the annealing process. This approach allowed us to determine the electronic contribution of the third-order nonlinear optical susceptibility χ{sup <3>}{sub elec} of these MPc films and to investigate two theoretical models for explanation of the observed results. We find that the annealing process significantly changes the optical and structural properties of MPc thin films. - Highlights: • Metallophtalocyanine thin films were grown by Physical Vapor Deposition technique. • MPcs thin films were undergone an annealing process in ambient atmosphere. • Third Harmonic spectra were measured to investigate nonlinear optical properties. • The third order nonlinear optical susceptibility χ{sup <3>}{sub elec} was determined. • We report changing both nonlinear optical and structural properties of thin films.

  5. Thermally enhanced optical nonlinearity in nematic liquid crystal close to phase transition temperature (United States)

    Shih, Chia-Chi; Chen, Yu-Jen; Hung, Wen-Chi; Jiang, I.-Min; Tsai, Ming-Shan


    This study investigates the beam profile and the liquid crystal (LC) arrangement affected by an optical field on LC thin films at a temperature close to nematic-isotropic phase transition temperature ( TNI). A combined microscopic and conoscopic technique was used in experiments as a convenient way to analyze the optical nonlinearity that is associated with the molecular configuration of nematic liquid crystal (NLC). An optical field combined with thermal enhancement enhances molecular reorientation and causes additional molecular excitation along the axis of propagation of the beam. The reorientational nonlinearity yields an undulating structure with multi-foci; the length between each pair of foci increases with time, as described.

  6. CW all optical self switching in nonlinear chalcogenide nano plasmonic directional coupler (United States)

    Motamed-Jahromi, Leila; Hatami, Mohsen


    In this paper we obtain the coupling coefficient of plasmonic directional coupler (PDC) made up of two parallel monolayer waveguides filled with high nonlinear chalcogenide material for TM mode in continues wave (CW) regime. In addition, we assume each waveguides acts as a perturbation to other waveguide. Four nonlinear-coupled equations are derived. Transfer distances are numerically calculated and used for deriving length of all optical switch. The length of designed switch is in the range of 10-1000 μm, and the switching power is in the range of 1-100 W/m. Obtained values are suitable for designing all optical elements in the integrated optical circuits.

  7. Evaluation of third order nonlinear optical parameters of CdS/PVA nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Mamta [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160014 (India); Department of Applied Sciences (Physics), UIET, Panjab University, Chandigarh-160014 (India); Tripathi, S. K., E-mail:, E-mail: [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160014 (India)


    CdS nanoparticles dispersed in PVA are prepared by Chemical method at room temperature. The nonlinear optical parameters such as nonlinear absorption (β), nonlinear refractive index (n{sub 2}) and nonlinear susceptibility (χ{sup 3}) are calculated for this sample by using Z-scan technique. CdS/PVA samples show the two photon absorption mechanism. The third order nonlinear susceptibility is calculated from n{sub 2} and β and is found to be of the order of 10{sup −7} – 10{sup −8} m{sup 2}/V{sup 2}. The larger value of third order nonlinear susceptibility is due to dielectric and quantum confinement effect.

  8. Nonlinear optics response of semiconductor quantum wells under high magnetic fields

    International Nuclear Information System (INIS)

    Chemla, D.S.


    Recent investigations on the nonlinear optical response of semiconductor quantum wells in a strong perpendicular magnetic field, H, are reviewed. After some introductory material the evolution of the linear optical properties of GaAs QW's as a function of H is discussed; an examination is made of how the magneto-excitons (MX) extrapolate continuously between quasi-2D QW excitons (X) when H = 0, and pairs of Landau levels (LL) when H → ∞. Next, femtosecond time resolved investigations of their nonlinear optical response are presented; the evolution of MX-MX interactions with increasing H is stressed. Finally, how, as the dimensionality is reduced by application of H, the number of scattering channels is limited and relaxation of electron-hole pairs is affected. How nonlinear optical spectroscopy can be exploited to access the relaxation of angular momentum within magneto-excitons is also discussed

  9. Linear and Nonlinear Optical Properties of Micrometer-Scale Gold Nanoplates

    International Nuclear Information System (INIS)

    Liu Xiao-Lan; Peng Xiao-Niu; Yang Zhong-Jian; Li Min; Zhou Li


    Micrometer-scale gold nanoplates have been synthesized in high yield through a polyol process. The morphology, crystal structure and linear optical extinction of the gold nanoplates have been characterized. These gold nanoplates are single-crystalline with triangular, truncated triangular and hexagonal shapes, exhibiting strong surface plasmon resonance (SPR) extinction in the visible and near-infrared (NIR) region. The linear optical properties of gold nanoplates are also investigated by theoretical calculations. We further investigate the nonlinear optical properties of the gold nanoplates in solution by Z-scan technique. The nonlinear absorption (NLA) coefficient and nonlinear refraction (NLR) index are measured to be 1.18×10 2 cm/GW and −1.04×10 −3 cm 2 /GW, respectively. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  10. A nonlinear plasmonic resonator for three-state all-optical switching

    KAUST Repository

    Amin, Muhammad


    A nonlinear plasmonic resonator design is proposed for three-state all-optical switching at frequencies including near infrared and lower red parts of the spectrum. The tri-stable response required for three-state operation is obtained by enhancing nonlinearities of a Kerr medium through multiple (higher order) plasmons excited on resonator\\'s metallic surfaces. Indeed, simulations demonstrate that exploitation of multiple plasmons equips the proposed resonator with a multi-band tri-stable response, which cannot be obtained using existing nonlinear plasmonic devices that make use of single mode Lorentzian resonances. Multi-band three-state optical switching that can be realized using the proposed resonator has potential applications in optical communications and computing. © 2014 Optical Society of America.

  11. Optical soliton solutions for two coupled nonlinear Schroedinger systems via Darboux transformation

    International Nuclear Information System (INIS)

    Zhang Haiqiang; Li Juan; Xu Tao; Zhang Yaxing; Hu Wei; Tian Bo


    In nonlinear optical fibers, the vector solitons can be governed by the systems of coupled nonlinear Schroedinger from polarized optical waves in an isotropic medium. Based on the Ablowitz-Kaup-Newell-Segur technology, the Darboux transformation method is successfully applied to two coupled nonlinear Schroedinger systems. With the help of symbolic computation, the bright vector one- and two-soliton solutions including one-peak and two-peak solitons are further constructed via the iterative algorithm of Darboux transformation. Through the figures for several sample solutions, the stable propagation and elastic collisions for these kinds of bright vector solitons are discussed and the possible applications are pointed out in optical communications and relevant optical experiments.In addition, the conserved quantities of such two systems, i.e., the energy, momentum and Hamiltonian, are also presented

  12. Optical super-resolution effect induced by nonlinear characteristics of graphene oxide films (United States)

    Zhao, Yong-chuang; Nie, Zhong-quan; Zhai, Ai-ping; Tian, Yan-ting; Liu, Chao; Shi, Chang-kun; Jia, Bao-hua


    In this work, we focus on the optical super-resolution effect induced by strong nonlinear saturation absorption (NSA) of graphene oxide (GO) membranes. The third-order optical nonlinearities are characterized by the canonical Z-scan technique under femtosecond laser (wavelength: 800 nm, pulse width: 100 fs) excitation. Through controlling the applied femtosecond laser energy, NSA of the GO films can be tuned continuously. The GO film is placed at the focal plane as a unique amplitude filter to improve the resolution of the focused field. A multi-layer system model is proposed to present the generation of a deep sub-wavelength spot associated with the nonlinearity of GO films. Moreover, the parameter conditions to achieve the best resolution (˜λ/6) are determined entirely. The demonstrated results here are useful for high density optical recoding and storage, nanolithography, and super-resolution optical imaging.

  13. Geometrical effect characterization of femtosecond-laser manufactured glass microfluidic chips based on optical manipulation of submicroparticles (United States)

    Kotsifaki, Domna G.; Mackenzie, Mark D.; Polydefki, Georgia; Kar, Ajoy K.; Makropoulou, Mersini; Serafetinides, Alexandros A.


    Microfluidic devices provide a platform with wide ranging applications from environmental monitoring to disease diagnosis. They offer substantive advantages but are often not optimized or designed to be used by nonexpert researchers. Microchannels of a microanalysis platform and their geometrical characterization are of eminent importance when designing such devices. We present a method that is used to optimize each microchannel within a device using high-throughput particle manipulation. For this purpose, glass-based microfluidic devices, with three-dimensional channel networks of several geometrical sizes, were fabricated by employing laser fabrication techniques. The effect of channel geometry was investigated by employing an optical tweezer. The optical trapping force depends on the flow velocity that is associated with the dimensions of the microchannel. We observe a linear dependence of the trapping efficiency and of the fluid flow velocity, with the channel dimensions. We determined that the highest trapping efficiency was achieved for microchannels with aspect ratio equal to one. Numerical simulation validated the impact of the device design dimensions on the trapping efficiency. This investigation indicates that the geometrical characteristics, the flow velocity, and trapping efficiency are crucial and should be considered when fabricating microfluidic devices for cell studies.

  14. Optoelectronic and nonlinear optical processes in low dimensional ...

    Indian Academy of Sciences (India)

    Abstract. Spatial confinement of quantum excitations on their characteristic wavelength scale in low dimen- sional materials offers unique possibilities to engineer the electronic structure and thereby control their physi- cal properties by way of simple manipulation of geometrical parameters. This has led to an overwhelming ...

  15. Natural Silk as a Photonics Component: a Study on Its Light Guiding and Nonlinear Optical Properties


    Kujala, Sami; Mannila, Anna; Karvonen, Lasse; Kieu, Khanh; Sun, Zhipei


    Silk fibers are expected to become a pathway to biocompatible and bioresorbable waveguides, which could be used to deliver localized optical power for various applications, e.g., optical therapy or imaging inside living tissue. Here, for the first time, the linear and nonlinear optical properties of natural silk fibers have been studied. The waveguiding properties of silk fibroin of largely unprocessed Bombyx mori silkworm silk are assessed using two complementary methods, and found to be on ...

  16. Nonlinear optics at the single-photon level inside a hollow core fiber

    DEFF Research Database (Denmark)

    Hofferberth, Sebastian; Peyronel, Thibault; Liang, Qiyu


    Cold atoms inside a hollow core fiber provide an unique system for studying optical nonlinearities at the few-photon level. Confinement of both atoms and photons inside the fiber core to a diameter of just a few wavelengths results in high electric field intensity per photon and large optical...... depths with a relatively small number of atoms. We present our experimental apparatus and discuss results regarding all-optical switching at ultra-low light levels....

  17. Harnessing mode-selective nonlinear optics for on-chip multi-channel all-optical signal processing

    Directory of Open Access Journals (Sweden)

    Ming Ma


    Full Text Available All-optical signal processing based on nonlinear optical effects allows for the realization of important functions in telecommunications including wavelength conversion, optical multiplexing/demultiplexing, Fourier transformation, and regeneration, amongst others, on ultrafast time scales to support high data rate transmission. In integrated photonic subsystems, the majority of all-optical signal processing systems demonstrated to date typically process only a single channel at a time or perform a single processing function, which imposes a serious limitation on the functionality of integrated solutions. Here, we demonstrate how nonlinear optical effects can be harnessed in a mode-selective manner to perform simultaneous multi-channel (two and multi-functional optical signal processing (i.e., regenerative wavelength conversion in an integrated silicon photonic device. This approach, which can be scaled to a higher number of channels, opens up a new degree of freedom for performing a broad range of multi-channel nonlinear optical signal processing functions using a single integrated photonic device.

  18. Adjustable third-order nonlinear optical properties of the spin coating phenoxazinium–PMMA films

    International Nuclear Information System (INIS)

    Miao, Jia-Tao; Sun, Ru; Yan, Bao-Long; Wu, Xing-Zhi; Song, Ying-Lin; Lu, Jian-Mei; Ge, Jian-Feng


    The third-order nonlinear optical properties of spin coating poly(methyl methacrylate) films doped with 3,7-bis(diethylamino)phenoxazin-5-ium chloride (1) are reported. The third-order nonlinear optical properties were tested by Z-scan technology with nanosecond laser beam at 532 nm. The third-order nonlinear absorptions change from reverse saturation absorption to saturation absorption with increasing percentage of the phenoxazinium dye in the poly(methyl methacrylate) film. The different forms of the spin coating films were obtained by atomic force microscopy and transmission electron microscope, and the different aggregation phenomenon of the phenoxazinium in the films can explain the adjustable third-order nonlinear absorption phenomena. Moreover, large third-order nonlinear optical susceptibilities (up to 10 −7  esu) and high second hyperpolarizabilities (up to 10 −28  esu) are found with these films. The results indicate that the phenoxazinium dye is the potential material for the third-order nonlinear optical application. - Highlights: • Third-order NLO properties of the phenoxazinium doped PMMA films were obtained. • Reverse saturated absorption changes to saturated absorption by the different percentage of phenoxazinium in the PMMA films. • Different states of films were obtained

  19. Optical biomarkers of serous and mucinous human ovarian tumor assessed with nonlinear optics microscopies. (United States)

    Adur, Javier; Pelegati, Vitor B; de Thomaz, Andre A; Baratti, Mariana O; Almeida, Diogo B; Andrade, L A L A; Bottcher-Luiz, Fátima; Carvalho, Hernandes F; Cesar, Carlos L


    Nonlinear optical (NLO) microscopy techniques have potential to improve the early detection of epithelial ovarian cancer. In this study we showed that multimodal NLO microscopies, including two-photon excitation fluorescence (TPEF), second-harmonic generation (SHG), third-harmonic generation (THG) and fluorescence lifetime imaging microscopy (FLIM) can detect morphological and metabolic changes associated with ovarian cancer progression. We obtained strong TPEF + SHG + THG signals from fixed samples stained with Hematoxylin & Eosin (H&E) and robust FLIM signal from fixed unstained samples. Particularly, we imaged 34 ovarian biopsies from different patients (median age, 49 years) including 5 normal ovarian tissue, 18 serous tumors and 11 mucinous tumors with the multimodal NLO platform developed in our laboratory. We have been able to distinguish adenomas, borderline, and adenocarcinomas specimens. Using a complete set of scoring methods we found significant differences in the content, distribution and organization of collagen fibrils in the stroma as well as in the morphology and fluorescence lifetime from epithelial ovarian cells. NLO microscopes provide complementary information about tissue microstructure, showing distinctive patterns for serous and mucinous ovarian tumors. The results provide a basis to interpret future NLO images of ovarian tissue and lay the foundation for future in vivo optical evaluation of premature ovarian lesions.

  20. Optical biomarkers of serous and mucinous human ovarian tumor assessed with nonlinear optics microscopies.

    Directory of Open Access Journals (Sweden)

    Javier Adur

    Full Text Available Nonlinear optical (NLO microscopy techniques have potential to improve the early detection of epithelial ovarian cancer. In this study we showed that multimodal NLO microscopies, including two-photon excitation fluorescence (TPEF, second-harmonic generation (SHG, third-harmonic generation (THG and fluorescence lifetime imaging microscopy (FLIM can detect morphological and metabolic changes associated with ovarian cancer progression.We obtained strong TPEF + SHG + THG signals from fixed samples stained with Hematoxylin & Eosin (H&E and robust FLIM signal from fixed unstained samples. Particularly, we imaged 34 ovarian biopsies from different patients (median age, 49 years including 5 normal ovarian tissue, 18 serous tumors and 11 mucinous tumors with the multimodal NLO platform developed in our laboratory. We have been able to distinguish adenomas, borderline, and adenocarcinomas specimens. Using a complete set of scoring methods we found significant differences in the content, distribution and organization of collagen fibrils in the stroma as well as in the morphology and fluorescence lifetime from epithelial ovarian cells.NLO microscopes provide complementary information about tissue microstructure, showing distinctive patterns for serous and mucinous ovarian tumors. The results provide a basis to interpret future NLO images of ovarian tissue and lay the foundation for future in vivo optical evaluation of premature ovarian lesions.

  1. Nonlinear optical rectification and optical absorption in GaAs-Ga1-xAlxAs asymmetric double quantum wells: Combined effects of applied electric and magnetic fields and hydrostatic pressure

    International Nuclear Information System (INIS)

    Karabulut, I.; Mora-Ramos, M.E.; Duque, C.A.


    The intersubband electron-related nonlinear optical absorption and nonlinear optical rectification in GaAs-Ga 1-x Al x As asymmetric double quantum wells are studied, under the influence of combined or independent applied electric and magnetic fields as well as hydrostatic pressure. The outcome of the density matrix formalism and the effective mass, and parabolic-band approximations have been considered as main theoretical tools for the description. It is obtained that under particular geometrical conditions, with or without electric and/or magnetic field strength, the optical rectification is null and, simultaneously, in such circumstances the optical absorption has a relative maximum. It is also detected that the influence of the hydrostatic pressure leads to increasing or decreasing behaviors of the nonlinear optical absorption in dependence of the particular regime of pressure values considered, with significant distinction of the cases of opposite electric field orientations. - Highlights: → Maxima of the NOA correspond to zero in the NOR. → Electric fields can couple the double quantum wells. → Hydrostatic pressure can couple the double quantum wells. → NOA can increase/decrease with hydrostatic pressure. → Overlap between wave functions depends on the magnetic field.

  2. Dynamics of Nonlinear Excitation of the High-Order Mode in a Single-Mode Step-Index Optical Fiber (United States)

    Burdin, V.; Bourdine, A.


    This work is concerned with approximate model of higher-order mode nonlinear excitation in a singlemode silica optical fiber. We present some results of simulation for step-index optical fiber under femtosecond optical pulse launching, which confirm ability of relatively stable higher-order mode excitation in such singlemode optical fiber over sufficiently narrow range of launched optical power variation.

  3. Nonlinear optical microscopy for histology of fresh normal and cancerous pancreatic tissues.

    Directory of Open Access Journals (Sweden)

    Wenyan Hu

    Full Text Available BACKGROUND: Pancreatic cancer is a lethal disease with a 5-year survival rate of only 1-5%. The acceleration of intraoperative histological examination would be beneficial for better management of pancreatic cancer, suggesting an improved survival. Nonlinear optical methods based on two-photon excited fluorescence (TPEF and second harmonic generation (SHG of intrinsic optical biomarkers show the ability to visualize the morphology of fresh tissues associated with histology, which is promising for real-time intraoperative evaluation of pancreatic cancer. METHODOLOGY/PRINCIPAL FINDINGS: In order to investigate whether the nonlinear optical imaging methods have the ability to characterize pancreatic histology at cellular resolution, we studied different types of pancreatic tissues by using label-free TPEF and SHG. Compared with other routine methods for the preparation of specimens, fresh tissues without processing were found to be most suitable for nonlinear optical imaging of pancreatic tissues. The detailed morphology of the normal rat pancreas was observed and related with the standard histological images. Comparatively speaking, the preliminary images of a small number of chemical-induced pancreatic cancer tissues showed visible neoplastic differences in the morphology of cells and extracellular matrix. The subcutaneous pancreatic tumor xenografts were further observed using the nonlinear optical microscopy, showing that most cells are leucocytes at 5 days after implantation, the tumor cells begin to proliferate at 10 days after implantation, and the extracellular collagen fibers become disordered as the xenografts grow. CONCLUSIONS/SIGNIFICANCE: In this study, nonlinear optical imaging was used to characterize the morphological details of fresh pancreatic tissues for the first time. We demonstrate that it is possible to provide real-time histological evaluation of pancreatic cancer by the nonlinear optical methods, which present an


    International Nuclear Information System (INIS)



    A method has been developed to measure and correct operationally the non-linear effects of the final focusing magnets in colliders, that gives access to the effects of multi-pole errors by applying closed orbit bumps, and analyzing the resulting tune and orbit shifts. This technique has been tested and used during 4 years of RHIC (the Relativistic Heavy Ion Collider at BNL) operations. I will discuss here the theoretical basis of the method, the experimental set-up, the correction results, the present understanding of the machine model, the potential and limitations of the method itself as compared with other non-linear correction techniques


    Energy Technology Data Exchange (ETDEWEB)



    A method has been developed to measure and correct operationally the non-linear effects of the final focusing magnets in colliders, that gives access to the effects of multi-pole errors by applying closed orbit bumps, and analyzing the resulting tune and orbit shifts. This technique has been tested and used during 4 years of RHIC (the Relativistic Heavy Ion Collider at BNL) operations. I will discuss here the theoretical basis of the method, the experimental set-up, the correction results, the present understanding of the machine model, the potential and limitations of the method itself as compared with other non-linear correction techniques.

  6. Dissipative dynamics of matter-wave solitons in a nonlinear optical lattice

    International Nuclear Information System (INIS)

    Abdullaev, F. Kh.; Tomio, Lauro; Gammal, A.; Luz, H. L. F. da


    Dynamics and stability of solitons in two-dimensional (2D) Bose-Einstein condensates (BEC), with one-dimensional (1D) conservative plus dissipative nonlinear optical lattices, are investigated. In the case of focusing media (with attractive atomic systems), the collapse of the wave packet is arrested by the dissipative periodic nonlinearity. The adiabatic variation of the background scattering length leads to metastable matter-wave solitons. When the atom feeding mechanism is used, a dissipative soliton can exist in focusing 2D media with 1D periodic nonlinearity. In the defocusing media (repulsive BEC case) with harmonic trap in one direction and nonlinear optical lattice in the other direction, the stable soliton can exist. Variational approach simulations are confirmed by full numerical results for the 2D Gross-Pitaevskii equation

  7. Ultrafast Relaxation Dynamics of the Optical Nonlinearity in Nanometric Gold Particles

    International Nuclear Information System (INIS)

    Puech, K.; Blau, W.J.


    Measurements of the resonantly enhanced, third-order nonlinear optical properties of gold nanostructures exhibiting reduced charge-carrier mobility in three dimensions were performed with a number of ultrafast nonlinear optical techniques. The size of the particles investigated was varied between 5 and 40 nm. The magnitude of the nonlinear susceptibility is of the order of 5.10 -16 m 2 V -2 at resonance and an order of magnitude lower off-resonance. The response time of the nonlinearity is found to be extremely fast and could not be resolved in the experiments undertaken here. The only statement that can be made in this regard is that the phase relaxation time is of the order of or less than 20 fs while the energy relaxation time is of the order of or less than 75 fs

  8. Nonlinear continuous-wave optical propagation in nematic liquid crystals: Interplay between reorientational and thermal effects. (United States)

    Alberucci, Alessandro; Laudyn, Urszula A; Piccardi, Armando; Kwasny, Michał; Klus, Bartlomiej; Karpierz, Mirosław A; Assanto, Gaetano


    We investigate nonlinear optical propagation of continuous-wave (CW) beams in bulk nematic liquid crystals. We thoroughly analyze the competing roles of reorientational and thermal nonlinearity with reference to self-focusing/defocusing and, eventually, the formation of nonlinear diffraction-free wavepackets, the so-called spatial optical solitons. To this extent we refer to dye-doped nematic liquid crystals in planar cells excited by a single CW beam in the highly nonlocal limit. To adjust the relative weight between the two nonlinear responses, we employ two distinct wavelengths, inside and outside the absorption band of the dye, respectively. Different concentrations of the dye are considered in order to enhance the thermal effect. The theoretical analysis is complemented by numerical simulations in the highly nonlocal approximation based on a semi-analytic approach. Theoretical results are finally compared to experimental results in the Nematic Liquid Crystals (NLC) 4-trans-4'-n-hexylcyclohexylisothiocyanatobenzene (6CHBT) doped with Sudan Blue dye.

  9. Size and direction of distortion in geometric-optical illusions: conciliation between the Müller-Lyer and Titchener configurations. (United States)

    Nemati, Farshad


    Over the past few decades, different theories have been advanced to explain geometric-optical illusions based on various perceptual processes such as assimilation and/or contrast. Consistent with the contradictory effects of assimilation and contrast, Pressey's assimilation theory provided an explanation for the Müller-Lyer illusion, but failed to account for the Titchener (Ebbinghaus) illusion. A model that explains both Müller-Lyer and Titchener illusions according to a common underlying process may outline a unified explanation for a variety of geometric-optical illusions. In order to develop such a model, the concept of empty space is introduced as an area of the illusory figure that is not filled by line drawings. It was predicted that the magnitude of illusion would increase with the area of the empty space around the illusory figures. The effect of empty space on the magnitude of perceptual distortion was measured in Müller-Lyer figures, with outward arrowheads of different length. The results indicated an overestimation of the target stimulus in all of the figures. Nevertheless, consistent with the prediction of the present model, the horizontal line in the Müller-Lyer figure with the longest arrowheads appeared shorter than that with the shortest arrowheads, although the size contrast of these figures was the same. According to the analysis proposed in the present study, the area of empty space not only affects the magnitude of illusion but also serves as a contextual cue for the perceptual system to determine the direction of illusion (orientation). The functional relationships between the size contrast and empty space provide a common explanation for the Müller-Lyer, Titchener, and a variety of other geometric-optical illusions.

  10. Enhancement of nonlinear optical properties of compounds of silica ...

    Indian Academy of Sciences (India)

    theory is exploited to replace the spherical nanoparticles with cylindrical and ellipsoidal ones, facil- itating the calculation of the third-order nonlinear effective ... associated with light scattering, whereby the electromagnetic potentials and fields are expanded by spherical harmonics [22,23]. Such solutions utilize the desirable ...

  11. Linear and nonlinear optical properties of borate crystals as ...

    Indian Academy of Sciences (India)


    Abstract. With the development of the state-of-the-art band calculation scheme and massively parallel pro- cessing in the high performance computing, we are now able to calculate all important physical properties, including (i) the nonlinear susceptibility; (ii) the multiphoton absorption rate; (iii) the birefringence; and (iv).

  12. Nonlinear coherent four-wave-mixing in optical microscopy

    NARCIS (Netherlands)

    Potma, Eric O.; Boeij, Wim P. de; Wiersma, Douwe A.


    We present a detailed theoretical analysis of the imaging properties of coherent nonlinear microscopes. We have developed a model that allows calculation of the generation and propagation of coherent signals under high numerical aperture (NA) conditions without invoking the slowly varying envelope

  13. Terahertz radiation from a nonlinear slab traversed by an optical pulse.


    Zinov’ev, N. N.; Nikoghosyan, A. S.; Chamberlain, J. M.


    We report on the theoretical calculations considering collinear electromagnetic radiation at the propagation of an optical pulse through a slab of nonlinear material. Calculated waveforms of the radiated field fit well to the experimental dependencies showing the remarkable similarities between the radiation at nonlinear wave interaction and the radiation phenomena of moving external charges, similarly to discussed in the Tamm Problem and transition radiation of moving external ch...

  14. Design of microstructured optical fibres made from highly nonlinear glasses for FWM-based telecom applications

    Czech Academy of Sciences Publication Activity Database

    Kaňka, Jiří


    Roč. 16, č. 25 (2008), s. 20395-20408 ISSN 1094-4087 R&D Projects: GA MŠk 1P05OC002; GA MŠk OE08021 Institutional research plan: CEZ:AV0Z20670512 Keywords : Nonlinear optics * Highly nonlinear fibres * Fibre design Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.880, year: 2008

  15. Enhancement of nonlinear optical (NLO) properties of indigo through modification of auxiliary donor, donor and acceptor (United States)

    Mahmood, Asif; Abdullah, Muhammad Imran; Khan, Salah Ud-Din


    In this study, indigo based dyes with high non-linear optical response have been investigated. Density functional theory (DFT) was used to study non-linear optical properties of indigo and newly designed dyes (IM-Dye-0, IM-Dye-1, IM-Dye-2 and IM-Dye-3). The time dependant density functional theory (TDDFT) was used to calculate the excitation energies. The HOMO-LUMO energy gaps of newly designed dyes were smaller as compare with indigo dye. Absorption maxima of newly designed dyes strongly red shifted as compare with indigo dye. High non-linear optical (NLO) response of newly designed dyes revealed that these materials would be excellent for NLO applications. This theoretical approach of designing will pave the way for experimentalists to synthesize high response NLO compound.

  16. Scrambled coherent superposition for enhanced optical fiber communication in the nonlinear transmission regime. (United States)

    Liu, Xiang; Chandrasekhar, S; Winzer, P J; Chraplyvy, A R; Tkach, R W; Zhu, B; Taunay, T F; Fishteyn, M; DiGiovanni, D J


    Coherent superposition of light waves has long been used in various fields of science, and recent advances in digital coherent detection and space-division multiplexing have enabled the coherent superposition of information-carrying optical signals to achieve better communication fidelity on amplified-spontaneous-noise limited communication links. However, fiber nonlinearity introduces highly correlated distortions on identical signals and diminishes the benefit of coherent superposition in nonlinear transmission regime. Here we experimentally demonstrate that through coordinated scrambling of signal constellations at the transmitter, together with appropriate unscrambling at the receiver, the full benefit of coherent superposition is retained in the nonlinear transmission regime of a space-diversity fiber link based on an innovatively engineered multi-core fiber. This scrambled coherent superposition may provide the flexibility of trading communication capacity for performance in future optical fiber networks, and may open new possibilities in high-performance and secure optical communications.

  17. Organometallic complexes for nonlinear optics. 42. Syntheses, linear, and nonlinear optical properties of ligated metal-functionalized oligo(p-phenyleneethynylene)s. (United States)

    Dalton, Gulliver T; Cifuentes, Marie P; Watson, Laurance A; Petrie, Simon; Stranger, Robert; Samoc, Marek; Humphrey, Mark G


    A combination of UV-vis-NIR spectroscopy, femtosecond Z-scan measurements, and time-dependent density functional theory (TD-DFT) calculations have been used to comprehensively investigate the linear optical and nonlinear optical (NLO) properties of pi-delocalizable metal-functionalized oligo(phenyleneethynylene)s. A range of unsymmetrically or symmetrically end-functionalized mono-, di-, tri-, penta-, hepta-, and nona(phenyleneethynylene)s were synthesized, with larger examples bearing varying numbers of 2,5-di(hexyloxy)phenyl groups to ensure sufficient solubility of the metal complex derivatives. The effect of incorporating varying numbers of solubilizing substituents in the OPE bridge, peripheral group modification, OPE lengthening, coligand variation, and metal location in the OPE on the linear optical properties has been established, with the first three molecular modifications resulting in significant changes in the optical absorption maxima. TD-DFT calculations reveal that the most intense transition in the linear optical spectra is localized on the OPE bridge and involves excitation from acetylenic to cumulenic molecular orbitals that are not greatly spatially separated from one another. The nonlinear optical properties are dominated by two-photon absorption, which for all but 1,4-{trans-[RuCl(dppm)(2)]C[triple bond]C}(2)C(6)H(4) appears as a band around 11,400 cm(-1) and a sharp increase of nonlinear absorption at frequencies >17,000 cm(-1). Surprisingly, there is relatively little influence of the length of the OPE bridge on the magnitude of the two-photon absorption cross sections, which are in the range 300-1000 GM.

  18. Laser-induced stimulated Raman scattering in the forward direction of a droplet - Comparison of Mie theory with geometrical optics (United States)

    Srivastava, Vandana; Jarzembski, Maurice A.


    This paper uses Mie theory to treat electromagnetic scattering and to evaluate field enhancement in the forward direction of a small droplet irradiated by a high-energy beam and compares the results of calculations with the field-enhancement evaluation obtained via geometrical optics treatment. Results of this comparison suggest that the field enhancement located at the critical ring region encircling the axis in the forward direction of the droplet can support laser-induced Raman scattering. The results are supported by experimental observations of the interaction of a 120-micron-diam water droplet with a high-energy Nd:YAG laser beam.

  19. Picosecond nonlinear optical studies of gold nanoparticles synthesised using coriander leaves (Coriandrum sativum) (United States)

    Venugopal Rao, S.


    The results are presented from the experimental picosecond nonlinear optical (NLO) studies of gold nanoparticles synthesised using coriander leaf (Coriandrum sativum) extract. Nanoparticles with an average size of ∼30 nm (distribution of 5-70 nm) were synthesised according to the procedure reported by Narayanan et al. [Mater. Lett. 2008, 62, 4588-4591]. NLO studies were carried out using the Z-scan technique using 2 ps pulses near 800 nm. Open-aperture data suggested saturation absorption as the nonlinear absorption mechanism, whereas closed-aperture data suggested a positive nonlinearity. The magnitude of third-order nonlinearity was estimated to be (3.3 ± 0.6) × 10-13 esu. A solvent contribution to the nonlinearity was also identified and estimated. A comparison is attempted with some recently reported NLO studies of similar gold nanostructures.

  20. Investigation of nonlinear optical properties of various organic materials by the Z-scan method (United States)

    Ganeev, R. A.; Boltaev, G. S.; Tugushev, R. I.; Usmanov, T.


    We have studied the nonlinear optical properties of various organic materials (vegetable oil, juice, wine, cognac, Coca-Cola and Fanta drinks, Nescafé coffee, tea, gasoline, clock oil, glycerol, and polyphenyl ether) that are used in everyday life. Their nonlinearities have been studied by the Z-scan method in the near-IR and visible spectral ranges. We have shown that the majority of samples possess a nonlinear absorption; however, some of the studied materials show a strong saturated absorption and nonlinear refraction. Red wine and glycerol proved to be the most interesting materials. For these samples, we have observed a change in the sign of the nonlinear absorption with increasing laser intensity, which was attributed to the competition between two-photon absorption and saturated absorption.

  1. Measurements of nonlinear optical properties of PVDF/ZnO using Z-scan technique

    Energy Technology Data Exchange (ETDEWEB)

    Shanshool, Haider Mohammed, E-mail: [Ministry of Science and Technology, Baghdad (Iraq); Yahaya, Muhammad [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor (Malaysia); Yunus, Wan Mahmood Mat [Department of Physics, Faculty of Science, University Putra Malaysia, Serdang (Malaysia); Abdullah, Ibtisam Yahya [Department of Physics, College of Science, University of Mosul, Mosul (Iraq)


    The nonlinear optical properties of ZnO nanoparticles dispersed in poly (vinylidene fluoride) (PVDF) polymer are investigated. PVDF/ZnO nanocomposites were prepared by mixing different concentrations of ZnO nanoparticles, as the filler, with PVDF, as the polymer matrix, using casting method. Acetone was used as a solvent for the polymer. FTIR spectra of the samples were analyzed thus confirming the formation of α and β phases. The absorbance spectra of the samples were obtained, thereby showing high absorption in the UV region. The linear absorption coefficient was calculated. The single-beam Z-scan technique was used to measure the nonlinear refractive index and the nonlinear absorption coefficient of the PVDF/ZnO nanocomposite samples. We observed that the nonlinear refractive index is in the order of 10{sup -13} cm{sup 2}/W with the negative sign, whereas the nonlinear absorption coefficient is in the order of 10{sup -8} cm/W. (author)

  2. Digital nonlinearity compensation in high-capacity optical communication systems considering signal spectral broadening effect. (United States)

    Xu, Tianhua; Karanov, Boris; Shevchenko, Nikita A; Lavery, Domaniç; Liga, Gabriele; Killey, Robert I; Bayvel, Polina


    Nyquist-spaced transmission and digital signal processing have proved effective in maximising the spectral efficiency and reach of optical communication systems. In these systems, Kerr nonlinearity determines the performance limits, and leads to spectral broadening of the signals propagating in the fibre. Although digital nonlinearity compensation was validated to be promising for mitigating Kerr nonlinearities, the impact of spectral broadening on nonlinearity compensation has never been quantified. In this paper, the performance of multi-channel digital back-propagation (MC-DBP) for compensating fibre nonlinearities in Nyquist-spaced optical communication systems is investigated, when the effect of signal spectral broadening is considered. It is found that accounting for the spectral broadening effect is crucial for achieving the best performance of DBP in both single-channel and multi-channel communication systems, independent of modulation formats used. For multi-channel systems, the degradation of DBP performance due to neglecting the spectral broadening effect in the compensation is more significant for outer channels. Our work also quantified the minimum bandwidths of optical receivers and signal processing devices to ensure the optimal compensation of deterministic nonlinear distortions.

  3. Synthesis, characterization and non-linear optical response of organophilic carbon dots

    KAUST Repository

    Bourlinos, Athanasios B.


    For the first time ever we report the nonlinear optical (NLO) properties of carbon dots (C-dots). The C-dots for these experiments were synthesized by mild pyrolysis of lauryl gallate. The resulting C-dots bear lauryl chains and, hence, are highly dispersible in polar organic solvents, like chloroform. Dispersions in CHCl3 show significant NLO response. Specifically, the C-dots show negative nonlinear absorption coefficient and negative nonlinear refraction. Using suspensions with different concentrations these parameters are quantified and compared to those of fullerene a well-known carbon molecule with proven NLO response. © 2013 Elsevier Ltd. All rights reserved.

  4. Application of the G'/G Expansion Method in Ultrashort Pulses in Nonlinear Optical Fibers

    Directory of Open Access Journals (Sweden)

    Jiang Xing-Fang


    Full Text Available With the increasing input power in optical fibers, the dispersion problem is becoming a severe restriction on wavelength division multiplexing (WDM. With the aid of solitons, in which the shape and speed can remain constant during propagation, it is expected that the transmission of nonlinear ultrashort pulses in optical fibers can effectively control the dispersion. The propagation of a nonlinear ultrashort laser pulse in an optical fiber, which fits the high-order nonlinear Schrödinger equation (NLSE, has been solved using the G'/G expansion method. Group velocity dispersion, self-phase modulation, the fourth-order dispersion, and the fifth-order nonlinearity of the high-order NLSE were taken into consideration. A series of solutions has been obtained such as the solitary wave solutions of kink, inverse kink, the tangent trigonometric function, and the cotangent trigonometric function. The results have shown that the G'/G expansion method is an effective way to obtain the exact solutions for the high-order NLSE, and it provides a theoretical basis for the transmission of ultrashort pulses in nonlinear optical fibers.

  5. Nonlinear Optical Signal Processing for Tbit/s Ethernet Applications

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Galili, Michael; Mulvad, Hans Christian Hansen


    detection in a delay-interferometer-balanced detector-based receiver, yielding a BER less than 10−9. We also present subsystems making serial optical Tbit/s systems compatible with standard Ethernet data for data centre applications and present Tbit/s results using, for instance silicon nanowires.......We review recent experimental demonstrations of Tbaud optical signal processing. In particular, we describe a successful 1.28 Tbit/s serial data generation based on single polarization 1.28 Tbaud symbol rate pulses with binary data modulation (OOK) and subsequent all-optical demultiplexing. We also...

  6. Web Platform for Sharing Modeling Software in the Field of Nonlinear Optics

    Directory of Open Access Journals (Sweden)

    Dubenskaya Julia


    Full Text Available We describe the prototype of a Web platform intended for sharing software programs for computer modeling in the rapidly developing field of the nonlinear optics phenomena. The suggested platform is built on the top of the HUBZero open-source middleware. In addition to the basic HUBZero installation we added to our platform the capability to run Docker containers via an external application server and to send calculation programs to those containers for execution. The presented web platform provides a wide range of features and might be of benefit to nonlinear optics researchers.

  7. Vibrational contributions to the second-order nonlinear optical properties of {pi}-conjugated structure acetoacetanilide

    Energy Technology Data Exchange (ETDEWEB)

    Ravikumar, C. [Centre for Molecular and Biophysics Research, Department of Physics, Mar Ivanios College, Thiruvananthapuram-695 015, Kerala (India); Hubert Joe, I., E-mail: [Centre for Molecular and Biophysics Research, Department of Physics, Mar Ivanios College, Thiruvananthapuram-695 015, Kerala (India); Sajan, D. [Centre for Molecular and Biophysics Research, Department of Physics, Mar Ivanios College, Thiruvananthapuram-695 015, Kerala (India)


    FT-Raman and IR spectra of the nonlinear optic (NLO) crystal, acetoacetanilide have been recorded and analyzed. The detailed interpretation of the vibrational spectra has been carried out with the aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology. The various intramolecular interactions that is responsible for the stabilization of the molecule was revealed by natural bond orbital analysis. The Kurtz and Perry powder reflection technique appeared to be very effective in studies of second-order nonlinear optical properties of the molecule.

  8. Nonlinear optical enhancement induced by synergistic effect of graphene nanosheets and CdS nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Baohua, E-mail:, E-mail:; Cao, Yawan; Wang, Chong; Wang, Ji; Gu, Yuzong, E-mail:, E-mail: [Institute of Microsystem, School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Wang, Fangfang [Key Laboratory of Infrared Imaging Materials and Detectors, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China)


    CdS nanocrystals are attached on graphene nanosheets and their nonlinear optical properties are investigated by picosecond Z-scan technique at 532 nm. We found that synergistic effect between the graphene and CdS makes a major enhancement on the nonlinear optical absorption of graphene/CdS nanohybrid in comparison with cooperative effect, and the synergistic improvement is restricted by nonradiative defects in hybrid. The synergistic mechanism involving the local field theory and charge transfer evolution is proposed.

  9. Nonlinear optics and solid-state lasers advanced concepts, tuning-fundamentals and applications

    CERN Document Server

    Yao, Jianquan


    This book covers the complete spectrum of nonlinear optics and all solid state lasers.The book integrates theory, calculations and practical design, technology, experimental schemes and applications. With the expansion and further development of Laser technology, the wavelength spectrum of Lasers had to be enlarged, even to be tunable which requires the use of nonlinear optical and Laser tunable technology. It systematically summarizes and integrates the analysis of international achievements within the last 20 years in this field. It will be helpful for university teachers, graduate students as well as engineers.

  10. Bulk growth, structure, optical properties and laser damage threshold of organic nonlinear optical crystals of Imidazolium L-Ascorbate (United States)

    Saripalli, Ravi Kiran; Bhat, H. L.; Elizabeth, Suja


    Bulk, transparent organic nonlinear optical (NLO) single-crystals of imidazolium L-Ascorbate (ImLA) were grown using slow-evaporation. Crystal structure was determined by single crystal X-ray diffraction analysis. Preliminary linear optical measurements through UV-Visible and infrared spectroscopy revealed good optical transmittance and a low near-UV cutoff wavelength at 256 nm. Kurtz and Perry powder test revealed that ImLA is a phase-matchable NLO material with a second harmonic generation (SHG) efficiency of 1.2 times larger than that of standard KH2PO4 (KDP). Laser damage thresholds were determined for ImLA.

  11. Size dependence of non-linear optical properties of SiO2 thin films containing InP nanocrystals (United States)

    Zheng, M. J.; Zhang, L. D.; Zhang, J. G.

    SiO2 composite thin films containing InP nanocrystals were fabricated by radio-frequency magnetron co-sputtering technique. The microstructure of the composite thin films was characterized by X-ray diffraction and Raman spectrum. The optical absorption band edges exhibit marked blueshift with respect to bulk InP due to strong quantum confinement effect. Non-linear optical absorption and non-linear optical refraction were studied by a Z-scan technique using a single Gaussian beam of a He-Ne laser (632.8 nm). We observed the saturation absorption and two-photon absorption in the composite films. An enhanced third-order non-linear optical absorption coefficient and non-linear optical refractive index were achieved in the composite films. The nonlinear optical properties of the films display the dependence on InP nanocrystals size.

  12. Large Scale Electromagnetic Computation on Nonlinear Optical Systems

    National Research Council Canada - National Science Library

    Moloney, J


    ...; (2) Full Vectorial Situation when the Characteristics Spatial Scales Approach the Wavelength of Light and Temporal Scales Peach a Single or Hall Optical Cycle; and (3) Double Clad Fiber Amplifiers and Lasers for High Brightness Applications.

  13. Growth and characterization of nonlinear optical single crystals: bis ...

    Indian Academy of Sciences (India)

    methoxy benzoate (C4MB) single crystals were successfully grown by the slow evaporation solution growth technique. The harvested crystals were subjected to single-crystal X-ray diffraction, spectral, optical, thermal and mechanical studies in ...

  14. Constitutive Modeling, Nonlinear Behavior, and the Stress-Optic Law (United States)


    uncrosslinked PIB following a step shear strain = 2.5. Solid curve is the linear fitting yielding the indicated stress optical coefficient. (top) Ratio of...and solutions. Figure 39 [30] shows that conformance to the stress optic law is maintained during stress relaxation of an uncrosslinked PIB for both...calculation only becoming evident for strain reversals. Figure 16. Stress measured for a PIB melt subjected to a shear strain of 1.77 at t = 0 that was

  15. Real-Time Implementation of Nonlinear Optical Processing Functions. (United States)


    advantageous optical computing scheme using the VGM technique. The VGM device is still in an early stage of development and much material research and...predicted theoretically. The origin of the VGM * effect is still in doubt, but the evidence strongly points to the converse flexoelectric effect. The...refraction. The index refraction can be varied y electro- optically in many materials ; the effect is particularly large in LCs where the change in

  16. Subreflector extension for improved efficiencies in Cassegrain antennas - GTD/PO analysis. [Geometrical Theory of Diffraction/Physical Optics (United States)

    Rahmat-Samii, Yahya


    Both offset and symmetric Cassegrain reflector antennas are used in satellite and ground communication systems. It is known that the subreflector diffraction can degrade the performance of these reflectors. A geometrical theory of diffraction/physical optics analysis technique is used to investigate the effects of the extended subreflector, beyond its optical rim, on the reflector efficiency and far-field patterns. Representative numerical results are shown for an offset Cassegrain reflector antenna with different feed illumination tapers and subreflector extensions. It is observed that for subreflector extensions as small as one wavelength, noticeable improvements in the overall efficiencies can be expected. Useful design data are generated for the efficiency curves and far-field patterns.

  17. Delayed Higher-Order Optical Nonlinearities in Noble Gases (United States)

    Tarazkar, Maryam; Romanov, Dmitri; Levis, Robert


    The role of higher-order Kerr effect (HOKE) in femtosecond laser filamentation is currently at the center of a controversy, as alleged crossover from positive to negative nonlinear refractive index at higher intensities was proposed to cause filament stabilization. Experimental evidence of HOKE crossover or lack thereof is being hotly debated. Motivated by this debate, we report the frequency-dependent nonlinear refractive index coefficients n2 and n4 for a series of atmospheric-pressure noble gases: helium, neon, argon, krypton, and xenon. The corresponding atomic hyperpolarizability coefficients are obtained via auxiliary static electric field approach developed on the basis of ab initio calculations implemented in Dalton program and performed at the CCSD level of theory with t-Aug-cc-PV5Z basis set. The n4 index is obtained using the relations between the degenerate six-wave mixing coefficient and some other frequency-dependent second hyperpolarizability coefficients, which can be calculated on the basis of n2via the auxiliary field approach. For all the investigated gases, the n4 indices are found to be positive over the wavelength range 300 nm-1500 nm. This result runs counter to the HOKE crossover hypothesis. The calculated n4 indices demonstrate considerable temporal dispersion, which progressively increases from helium to xenon. This feature implies delayed nonlinearity and calls for modifications in current theoretical models of filamentation process. We gratefully acknowledge financial support through AFOSR MURI Grant No. FA9550-10-1-0561.

  18. Electric field and impurity effect on nonlinear optical rectification of a double cone like quantum dot (United States)

    Bahramiyan, H.


    In this work, we have investigated the effect of electric field and impurity position on nonlinear optical rectification of a double cone like quantum dot in the effective mass approximation and by using compact density-matrix formalism. We have calculated the energy levels and wave functions using finite element method (FEM) in the presence of impurity and influence of electric field. The results show that: (i) the binding energy changes with the impurity position and it is changed by the applied electric field, (ii) nonlinear optical rectification peak position of this system present the blue or red shift due to the applied electric field and changing the impurity position. (iii) for low electric field, impurity position plays an important role in electronic and optical properties, but for larger electric field, impurity position role becomes non-significant. (iv) the optical rectification changes due to the impurity position and the electric field are considerable.

  19. Acousto-Plasmonic Sensing Assisted by Nonlinear Optical Interactions in Bimetallic Au-Pt Nanoparticles

    Directory of Open Access Journals (Sweden)

    Eric Abraham Hurtado-Aviles


    Full Text Available A strong influence of mechanical action in nonlinear optical transmittance experiments with bimetallic nanoparticles integrated by gold and platinum was observed. The nanostructured samples were synthesized by a sol-gel method and contained in an ethanol suspension. UV-VIS spectroscopy evaluations, Transmission electron microscopy studies and input-output laser experiments were characterized. A two-photon absorption effect was induced by nanosecond pulses at 532 nm wavelength with an important contribution from the plasmonic response of the nanomaterials. All-optical identification of acoustical waves was remarkably improved by optical nonlinearities. High sensitivity for instrumentation of mechano-optical signals sensing particular fluids was demonstrated by using a variable carbon dioxide incorporation to the system.

  20. Synthesis, growth and characterization of π conjugated organic nonlinear optical chalcone derivative

    Energy Technology Data Exchange (ETDEWEB)

    Prabhu, A.N., E-mail: [Department of Physics, Manipal Institute of Technology, Manipal University, Manipal 576 104 (India); Upadhyaya, V. [Department of Physics, Manipal Institute of Technology, Manipal University, Manipal 576 104 (India); Jayarama, A., E-mail: [Department of Physics, Mangalore Institute of Technology and Engineering (MITE), Moodabidri 574225 (India); Subrahmanya Bhat, K. [Department of Chemistry, Manipal Institute of Technology, Manipal University, Manipal 576 104 (India)


    A new potentially useful nonlinear optical organic material, 1-(5-chlorothiophen-2-yl)-3-(2,3-dimethoxyphenyl)prop-2-en-1-one, has been synthesized and grown as a high-quality single crystal by the slow evaporation technique. The grown crystals were characterized by FT-IR, NMR, thermal analysis, and UV–visible spectroscopy. The material is thermally stabile up to 111 °C. The mechanical property of the grown crystals was studied using Vickers microhardness tester and the load dependence hardness was observed. The third order nonlinear optical properties of the material such as real and imaginary part of χ{sup (3)}, nonlinear absorption coefficient and nonlinear refractive index were determined using nanosecond laser pulses at 532 nm wavelength by employing Z-scan technique. The nonlinear refractive index is found to be of the order of 10{sup −11} cm{sup 2} W{sup −1}. The magnitude of third order susceptibility is of the order of 10{sup −13} esu. The observed increase in the third order nonlinearity in these molecules clearly indicates the electronic origin. The compounds exhibit good optical limiting at 532 nm. The best optical limiting behavior of this molecule is due to the substituted strong electron donor. - Highlights: ► A novel thiophene substituted NLO crystal has been grown using methanol as solvent. ► The crystals were characterized by using FTIR, TGA/DTA and UV–visible spectroscopy. ► The n{sub 2} and χ{sup (3)} values is of the order of 10{sup −11} cm{sup 2} W{sup −1} and 10{sup −13} esu respectively. ► The crystals show better optical limiting behavior.

  1. Study on third-order nonlinear optical properties of 4-methylsulfanyl chalcone derivatives using picosecond pulses

    Energy Technology Data Exchange (ETDEWEB)

    D' silva, E.D., E-mail: [Department of Studies in Physics, Mangalore University, Mangalagangotri, Mangalore 574199 (India); Podagatlapalli, G. Krishna [Advanced Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Hyderabad 500046 (India); Venugopal Rao, S., E-mail: [Advanced Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Hyderabad 500046 (India); Dharmaprakash, S.M. [Department of Studies in Physics, Mangalore University, Mangalagangotri, Mangalore 574199 (India)


    Graphical abstract: Photograph and schematic representation of Z-scan experimental setup used to investigate third order nonlinear properties of the chalcone materials. Highlights: ► Br and NO{sub 2} substituted chalcone derivatives were exposed to picosecond laser pulses. ► Third-order nonlinear optical (NLO) properties were investigated. ► Compounds show promising third-order and optical limiting properties. ► These materials found suitable for electrical and optical applications. -- Abstract: In this paper we present results from the experimental study of third-order nonlinear optical (NLO) properties of three molecules of Br and NO{sub 2} substituted chalcone derivatives namely (2E)-1-(4-bromophenyl)-3-[4(methylsulfanyl)phenyl]prop-2-en-1-one (4Br4MSP), (2E)-1-(3-bromophenyl)-3-[4-(methylsulfanyl) phenyl]prop-2-en-1-one (3Br4MSP) and (2E)-3[4(methylsulfanyl) phenyl]-1-(4-nitrophenyl)prop-2-en-1-one (4N4MSP). The NLO properties have been investigated by Z-scan technique using 2 ps laser pulses at 800 nm. The nonlinear refractive indices, nonlinear absorption coefficient, and the magnitude of third-order susceptibility have been determined. The values obtained are of the order of 10{sup −7} cm{sup 2}/GW, 10{sup −3} cm/GW and 10{sup −14} esu respectively. The molecular second hyperpolarizability for the chalcone derivatives is of the order of 10{sup −32} esu. The coupling factor, excited state cross section, ground state cross section etc. were determined. The optical limiting (OL) property was studied. The results suggest that the nonlinear properties investigated for present chalcones are comparable with some of the reported chalcone derivatives and can be desirable for NLO applications.

  2. Nonlinear optical properties of poly(methyl methacrylate) thin films doped with Bixa Orellana dye

    Energy Technology Data Exchange (ETDEWEB)

    Zongo, S., E-mail: [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, POBox 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 OldFaure road, Somerset West 7129, POBox 722, Somerset West, Western Cape Province (South Africa); Kerasidou, A.P. [LUNAM Université, Université d’Angers, CNRS UMR 6200, Laboratoire MOLTECH-Anjou, 2 Bd Lavoisier, 49045 Angers Cedex (France); Sone, B.T.; Diallo, A. [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, POBox 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 OldFaure road, Somerset West 7129, POBox 722, Somerset West, Western Cape Province (South Africa); Mthunzi, P. [Council for Scientific and Industrial Research, P O Box 395, Pretoria 0001 (South Africa); Iliopoulos, K. [LUNAM Université, Université d’Angers, CNRS UMR 6200, Laboratoire MOLTECH-Anjou, 2 Bd Lavoisier, 49045 Angers Cedex (France); Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas (FORTH/ICE-HT), 26504 Patras (Greece); Nkosi, M. [Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 OldFaure road, Somerset West 7129, POBox 722, Somerset West, Western Cape Province (South Africa); and others


    Highlights: • We studied the linear and nonlinear optical properties of hybrid Bixa Orellana dye doped PMMA thin film. • We investigated the linear optical properties by means of UV/Vis, FTIR and Fluorescence. • We used Tauc - Lorentz model to evaluate linear optical parameters (n &k) with relative maximum of 1.456 at 508.5, 523.79 and 511.9 nm for n is observed while the maximum of k varies from 0.070 to 0.080. • We evaluated nonlinear third order susceptibility which was found to be 1.00 × 10{sup −21} m{sup 2} V{sup −2} or 0.72 × 10{sup −13} esu. - Abstract: Natural dyes with highly delocalized π-electron systems are considered as promising organic materials for nonlinear optical applications. Among these dyes, Bixa Orellana dye with extended π-electron delocalization is one of the most attractive dyes. Bixa Orellana dye-doped Poly(methyl methacrylate) (PMMA) thin films were prepared through spin coating process for linear and nonlinear optical properties investigation. Atomic force microscopy (AFM) was used to evaluate the roughness of the thin films. The optical constants n and k were evaluated by ellipsometric spectroscopy. The refractive index had a maximum of about 1.456 at 508.5, 523.79 and 511.9 nm, while the maximum of k varies from 0.070 to 0.080 with the thickness. The third order nonlinear optical properties of the hybrid Bixa Orellana dye-PMMA polymer were investigated under 30 ps laser irradiation at 1064 nm with a repetition rate of 10 Hz. In particular the third-order nonlinear susceptibility has been determined by means of the Maker Fringes technique. The nonlinear third order susceptibility was found to be 1.00 × 10{sup −21} m{sup 2} V{sup −2} or 0.72 × 10{sup −13} esu. Our studies provide concrete evidence that the hybrid-PMMA composites of Bixa dye are prospective candidates for nonlinear material applications.

  3. Geometrically complex 3D-printed phantoms for diffuse optical imaging. (United States)

    Dempsey, Laura A; Persad, Melissa; Powell, Samuel; Chitnis, Danial; Hebden, Jeremy C


    Tissue-equivalent phantoms that mimic the optical properties of human and animal tissues are commonly used in diffuse optical imaging research to characterize instrumentation or evaluate an image reconstruction method. Although many recipes have been produced for generating solid phantoms with specified absorption and transport scattering coefficients at visible and near-infrared wavelengths, the construction methods are generally time-consuming and are unable to create complex geometries. We present a method of generating phantoms using a standard 3D printer. A simple recipe was devised which enables printed phantoms to be produced with precisely known optical properties. To illustrate the capability of the method, we describe the creation of an anatomically accurate, tissue-equivalent premature infant head optical phantom with a hollow brain space based on MRI atlas data. A diffuse optical image of the phantom is acquired when a high contrast target is inserted into the hollow space filled with an aqueous scattering solution.

  4. Second order optical nonlinearity in silicon by symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Cazzanelli, Massimo, E-mail: [Laboratorio IdEA, Dipartimento di Fisica, Università di Trento, via Sommarive, 14 Povo (Trento) (Italy); Schilling, Joerg, E-mail: [Centre for Innovation Competence SiLi-nano, Martin-Luther-University Halle-Wittenberg, Karl-Freiherr-von-Fritsch Str. 3, 06120 Halle (Germany)


    Although silicon does not possess a dipolar bulk second order nonlinear susceptibility due to its centro-symmetric crystal structure, in recent years several attempts were undertaken to create such a property in silicon. This review presents the different sources of a second order susceptibility (χ{sup (2)}) in silicon and the connected second order nonlinear effects which were investigated up to now. After an introduction, a theoretical overview discusses the second order nonlinearity in general and distinguishes between the dipolar contribution—which is usually dominating in non-centrosymmetric structures—and the quadrupolar contribution, which even exists in centro-symmetric materials. Afterwards, the classic work on second harmonic generation from silicon surfaces in reflection measurements is reviewed. Due to the abrupt symmetry breaking at surfaces and interfaces locally a dipolar second order susceptibility appears, resulting in, e.g., second harmonic generation. Since the bulk contribution is usually small, the study of this second harmonic signal allows a sensitive observation of the surface/interface conditions. The impact of covering films, strain, electric fields, and defect states at the interfaces was already investigated in this way. With the advent of silicon photonics and the search for ever faster electrooptic modulators, the interest turned to the creation of a dipolar bulk χ{sup (2)} in silicon. These efforts have been focussing on several experiments applying an inhomogeneous strain to the silicon lattice to break its centro-symmetry. Recent results suggesting the impact of electric fields which are exerted from fixed charges in adjacent covering layers are also included. After a subsequent summary on “competing” concepts using not Si but Si-related materials, the paper will end with some final conclusions, suggesting possible future research direction in this dynamically developing field.

  5. Extreme non-linear elasticity and transformation optics

    DEFF Research Database (Denmark)

    Gersborg, Allan Roulund; Sigmund, Ole


    realizations correspond to minimizers of elastic energy potentials for extreme values of the mechanical Poisson's ratio ν . For TE (Hz) polarized light an incompressible transformation ν = 1/2 is ideal and for TM (E z) polarized light one should use a compressible transformation with negative Poissons's ratio...... ν = -1. For the TM polarization the mechanical analogy corresponds to a modified Liao functional known from the transformation optics literature. Finally, the analogy between ideal transformations and solid mechanical material models automates and broadens the concept of transformation optics...

  6. Multi-mode dynamics of optical oscillators based on intracavity nonlinear frequency down-conversion (United States)

    Morozov, Yuri A.


    The transient power characteristics of two optical oscillators—a difference frequency generator (ICDFG) and a singly resonant optical parametric oscillator (ICSRO)—based on intracavity nonlinear optical frequency conversion, are described. The simulation has been performed via the rate-equation mathematical model, which features a multi-mode behavior of all optical fields. The reason for unattainability of single-mode emission in these devices without an additional frequency-selective element (e.g., a Fabry-Perot etalon) is clarified. It is shown that the dynamics of a short-wavelength emission (pump) results mainly from the nonlinear optical interaction, while that of the longer-wavelength optical fields (signal and idler) depends on selectivity of the etalon. With the suitable etalons inserted in their cavities, both devices are shown to operate dynamically single-mode under conventional experimental conditions. The nonlinear interaction makes the pump emission collapse to the single-mode operation very fast (it takes no more than a few tens of the photon lifetimes). To overcome the threshold of parametric generation, the intracavity pump power in the ICSRO has to exceed ˜ 100 W, while the ICDFG is essentially a "thresholdless" device.

  7. Single-pulse CARS based multimodal nonlinear optical microscope for bioimaging. (United States)

    Kumar, Sunil; Kamali, Tschackad; Levitte, Jonathan M; Katz, Ori; Hermann, Boris; Werkmeister, Rene; Považay, Boris; Drexler, Wolfgang; Unterhuber, Angelika; Silberberg, Yaron


    Noninvasive label-free imaging of biological systems raises demand not only for high-speed three-dimensional prescreening of morphology over a wide-field of view but also it seeks to extract the microscopic functional and molecular details within. Capitalizing on the unique advantages brought out by different nonlinear optical effects, a multimodal nonlinear optical microscope can be a powerful tool for bioimaging. Bringing together the intensity-dependent contrast mechanisms via second harmonic generation, third harmonic generation and four-wave mixing for structural-sensitive imaging, and single-beam/single-pulse coherent anti-Stokes Raman scattering technique for chemical sensitive imaging in the finger-print region, we have developed a simple and nearly alignment-free multimodal nonlinear optical microscope that is based on a single wide-band Ti:Sapphire femtosecond pulse laser source. Successful imaging tests have been realized on two exemplary biological samples, a canine femur bone and collagen fibrils harvested from a rat tail. Since the ultra-broad band-width femtosecond laser is a suitable source for performing high-resolution optical coherence tomography, a wide-field optical coherence tomography arm can be easily incorporated into the presented multimodal microscope making it a versatile optical imaging tool for noninvasive label-free bioimaging.

  8. Beam-Based Nonlinear Optics Corrections in Colliders

    CERN Document Server

    Pilat, Fulvia Caterina; Malitsky, Nikolay; Ptitsyn, Vadim


    A method has been developed to measure and correct operationally the non-linear effects of the final focusing magnets in colliders, which gives access to the effects of multi-pole errors by applying closed orbit bumps, and analyzing the resulting tune and orbit shifts. This technique has been tested and used during 3 years of RHIC (the Relativistic Heavy Ion Collider at BNL) operations. I will discuss here the theoretical basis of the method, the experimental set-up, the correction results, the present understanding of the machine model, the potential and limitations of the method itself as compared with other non linear correction techniques.

  9. Nonlinear optical response of relativistic energy bands: Application to phosphorene (United States)

    Pedersen, Thomas Garm


    The energy dispersion relation of massive relativistic particles is characterized by a gradual transition from parabolic to linear momentum dependence. A similar pseudorelativistic behavior is found in the energy bands of certain two-dimensional semiconductors. Focusing on phosphorene, we investigate the response of pseudorelativistic electrons to electromagnetic fields. It is demonstrated that a near-analytical expression for the induced current containing the field to all orders can be obtained. We analyze the harmonic content of the current and study the field-, frequency-, and band-gap dependence of the nonlinear response. A detailed analysis of third-harmonic generation and saturable absorption is made.

  10. Nonlinear optical control of Josephson coupling in cuprates

    Energy Technology Data Exchange (ETDEWEB)

    Casandruc, Eliza


    In High-T{sub C} cuprates superconducting Cu-O planes alternate with insulating layers along the crystallographic c-axis, making the materials equivalent to Josephson junctions connected in series. The most intriguing consequence is that the out-of-plane superconducting transport occurs via Cooper pairs tunneling across the insulating layers and can be predicted by the Josephson tunneling equations. Nonlinear interaction between light fields and the superconducting carriers serves as a powerful dynamical probe of cuprates, while offering opportunities for controlling them in an analogous fashion to other stimuli such as pressure and magnetic fields. The main goal of this thesis work is to use intense transient light fields to control the interlayer superconducting transport on ultrafast time scales. This was achieved by tuning the wavelength of such light pulses to completely different ranges, in order to either directly excite Josephson Plasma Waves in the nonlinear regime, or efficiently melt the competing charge and spin order phase, which in certain cuprates quenches the Josephson tunneling at equilibrium. In a first study, I have utilized strong field terahertz transients with frequencies tuned to the Josephson plasma resonance (JPR) to coherently control the c-axis superconducting transport. The Josephson relations have a cubic nonlinearity which is exploited to achieve two related, albeit slightly different, phenomena. Depending on the driving pulse, solitonic breathers were excited with narrow-band multi-cycle pulses in La{sub 1.84}Sr{sub 0.16}CuO{sub 4} while broad-band half-cycle pulses were employed to achieve a parametric amplification of Josephson Plasma Waves in La{sub 1.905}Ba{sub 0.095}CuO{sub 4}. These experiments are supported by extensive modeling, showing exceptional agreement. A comprehensive study illustrates the strong enhancement of the nonlinear effects near the JPR frequency. Then, I turned to investigate the competition between

  11. Large third-order optical nonlinearity of silver colloids in silica glasses synthesized by ion implantation

    International Nuclear Information System (INIS)

    Ghosh, Binita; Chakraborty, Purushottam


    Silver ion implantations in fused silica glasses have been made to synthesize silver nanocluster-glass composites and a combination of 'Anti-Resonant Interferometric Nonlinear Spectroscopy (ARINS)' and 'Z-scan' techniques has been employed for the measurement of the third-order optical susceptibility of these nanocomposites. The ARINS technique utilizes the dressing of two unequal-intensity counter-propagating pulsed optical beams with differential nonlinear phases, which occurs upon traversing the sample. This difference in phase manifests itself in the intensity-dependent transmission, measurement of which enables us to extract the values of nonlinear refractive index (η 2 ) and nonlinear absorption coefficient (β), finally yielding the real and imaginary parts of the third-order dielectric susceptibility (χ (3) ). The real and imaginary parts of χ (3) are obtained in the orders of 10 -10 e.s.u for silver nanocluster-glass composites. The present value of χ (3) , to our knowledge, is extremely accurate and much more reliable compared to the values previously obtained by other workers for similar silver-glass nanocomposites using only Z-scan technique. Optical nonlinearity has been explained to be due to two-photon absorption in the present nanocomposite glasses and is essentially of electronic origin.

  12. Effects of graphene quantum dots on linear and nonlinear optical behavior of malignant ovarian cells (United States)

    Mohajer, Salman; Ara, Mohammad Hossein Majles; Serahatjoo, Leila


    We investigate linear and nonlinear optical properties of standard human ovarian cancer cells (cell line: A2780cp) in vitro. Cells were treated by graphene quantum dots (GQDs) with two special concentrations. Nontoxicity of GQDs was examined in standard biological viability tests. Cancerous cells were fixed on a glass slide; then, interaction of light with biofilms was studied in linear and nonlinear regimes. Absorption spectra of untreated biofilms and biofilms with two different concentrations of GQDs was studied by UV-visible spectrophotometer. Optical behavior of biofilms in a linear regime of intensity (with low-intensity laser exposure) was reported using a simple optical setup. After that, we compared the attenuation of light in biofilm of cancerous cells with and without GQDs. Nonlinear behavior of these biofilms was investigated by a Z-scan setup using a continued wave He-Ne laser. Results showed that GQDs decreased the extinction coefficient and changed the sign and exact value of the nonlinear refractive index of malignant ovarian cells noticeably. The nonlinear refractive index of studied cells with no GQDs treatment was in the order of 10-8 (cm2/w) with a positive sign. This quantity changed to the same order of magnitude with a negative sign after GQDs treatment. Thus, GQDs can be used for cancer diagnosis under laser irradiation.

  13. Theory of plasmonic effects in nonlinear optics: the case of graphene (United States)

    Rostami, Habib; Katsnelson, Mikhail I.; Polini, Marco; Mikhail I. Katsnelson Collaboration; Habib Rostami; Marco Polini Collaboration

    The nonlinear optical properties of two-dimensional electronic systems are beginning to attract considerable interest both in the theoretical and experimental sectors. Recent experiments on the nonlinear optical properties of graphene reveal considerably strong third harmonic generation and four-wave mixing of this single-atomic-layer electronic system. We develop a large-N theory of electron-electron interaction corrections to multi-legged Feynman diagrams describing second- and third-order nonlinear response functions. Our theory is completely general and is useful to understand all second- and third-order nonlinear effects, including harmonic generation, wave mixing, and photon drag. We apply our theoretical framework to the case of graphene, by carrying out microscopic calculations of the second- and third-order nonlinear response functions of an interacting two-dimensional gas of massless Dirac fermions. We compare our results with recent measurements, where all-optical launching of graphene plasmons has been achieved. This work was supported by Fondazione Istituto Italiano di Tecnologia, the European Union's Horizon 2020 research and innovation programme under Grant agreement No. 696656 GrapheneCore, and the ERC Advanced Grant 338957 FEMTO/NANO (M.I.K.).


    Directory of Open Access Journals (Sweden)



    Full Text Available A theoretical study is carried out to evaluate the performance of an opticalwavelength division multiplexing (WDM network transmission system in the presenceof crosstalk due to optical fiber nonlinearities. The most significant nonlinear effects inthe optical fiber which are Cross-Phase Modulation (XPM, Four-Wave Mixing (FWM,and Stimulated Raman Scattering (SRS are investigated. Four types of optical fiber areincluded in the analysis; these are: single-mode fiber (SMF, dispersion compensationfiber (DCF, non-zero dispersion fiber (NZDF, and non-zero dispersion shifted fiber(NZDSF. The results represent the standard deviation of nonlinearity induced crosstalknoise power due to FWM and SRS, XPM power penalty for SMF, DCF, NZDF, andNZDSF types of fiber, besides the Bit Error Rate (BER for the three nonlinear effectsusing standard fiber type (SMF. It is concluded that three significant fiber nonlinearitiesare making huge limitations against increasing the launched power which is desired,otherwise, lower values of launched power limit network expansion including length,distance, covered areas, and number of users accessing the WDM network, unlesssuitable precautions are taken to neutralize the nonlinear effects. Besides, various fibertypes are not behaving similarly towards network parameters.

  15. Effect of concentration on the plasmonic absorption and optical nonlinearity of gold nanoparticles (United States)

    Rashidian, Morvarid; Dorranian, Davoud


    The effect of concentration on the optical nonlinearity of gold nanoparticles is investigated. Gold nanoparticles were synthesized by nanosecond-pulsed laser ablation of a high-purity gold plate in distilled water. The size of nanoparticles was measured using dynamic light scattering (DLS) method and was calculated from full width half maximum of their plasmonic absorption peak using Mie theory. Different nonlinear characteristics of gold nanoparticles are observed by considering their effects under irradiation with a second harmonic beam of a continuous-wave low power Nd-YAG laser at 532 nm. Low-power optical limiting with low limiting threshold is obtained in the sample using different apertures at different points of the laser beam path. The nonlinear optical responses are characterized by measuring the intensity dependent refractive index of medium using the z-scan technique. Results show that the linear absorption coefficient and nonlinear refractive index of samples are increased with increasing the concentration of gold nanoparticles in distilled water. Increasing the intensity of the probe beam leads to increasing the magnitude of nonlinear refractive index.

  16. Large third-order optical nonlinearity of silver colloids in silica glasses synthesized by ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Binita [Surface Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India); Chakraborty, Purushottam, E-mail: [Surface Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India)


    Silver ion implantations in fused silica glasses have been made to synthesize silver nanocluster-glass composites and a combination of 'Anti-Resonant Interferometric Nonlinear Spectroscopy (ARINS)' and 'Z-scan' techniques has been employed for the measurement of the third-order optical susceptibility of these nanocomposites. The ARINS technique utilizes the dressing of two unequal-intensity counter-propagating pulsed optical beams with differential nonlinear phases, which occurs upon traversing the sample. This difference in phase manifests itself in the intensity-dependent transmission, measurement of which enables us to extract the values of nonlinear refractive index ({eta}{sub 2}) and nonlinear absorption coefficient ({beta}), finally yielding the real and imaginary parts of the third-order dielectric susceptibility ({chi}{sup (3)}). The real and imaginary parts of {chi}{sup (3)} are obtained in the orders of 10{sup -10} e.s.u for silver nanocluster-glass composites. The present value of {chi}{sup (3)}, to our knowledge, is extremely accurate and much more reliable compared to the values previously obtained by other workers for similar silver-glass nanocomposites using only Z-scan technique. Optical nonlinearity has been explained to be due to two-photon absorption in the present nanocomposite glasses and is essentially of electronic origin.

  17. Geometrically unrestricted, topologically constrained control of liquid crystal defects using simultaneous holonomic magnetic and holographic optical manipulation (United States)

    Varney, Michael C. M.; Jenness, Nathan J.; Smalyukh, Ivan I.


    Despite the recent progress in physical control and manipulation of various condensed matter, atomic, and particle systems, including individual atoms and photons, our ability to control topological defects remains limited. Recently, controlled generation, spatial translation, and stretching of topological point and line defects have been achieved using laser tweezers and liquid crystals as model defect-hosting systems. However, many modes of manipulation remain hindered by limitations inherent to optical trapping. To overcome some of these limitations, we integrate holographic optical tweezers with a magnetic manipulation system, which enables fully holonomic manipulation of defects by means of optically and magnetically controllable colloids used as "handles" to transfer forces and torques to various liquid crystal defects. These colloidal handles are magnetically rotated around determined axes and are optically translated along three-dimensional pathways while mechanically attached to defects, which, combined with inducing spatially localized nematic-isotropic phase transitions, allow for geometrically unrestricted control of defects, including previously unrealized modes of noncontact manipulation, such as the twisting of disclination clusters. These manipulation capabilities may allow for probing topological constraints and the nature of defects in unprecedented ways, providing the foundation for a tabletop laboratory to expand our understanding of the role defects play in fields ranging from subatomic particle physics to early-universe cosmology.

  18. Modeling of Nonlinear Optical Response in Gaseous Media and Its Comparison with Experiment (United States)

    Xia, Yi

    This thesis demonstrates the model and application of nonlinear optical response with Metastable Electronic State Approach (MESA) in ultrashort laser propagation and verifies accuracy of MESA through extensive comparison with experimental data. The MESA is developed from quantum mechanics to describe the nonlinear off-resonant optical response together with strong-field ionization in gaseous medium. The conventional light-matter interaction models are based on a piece-wise approach where Kerr effect and multi-photon ionization are treated as independent nonlinear responses. In contrast, MESA is self-consistent as the response from freed electrons and bound electrons are microscopically linked. It also can be easily coupled to the Unidirectional Pulse Propagation Equations (UPPE) for large scale simulation of experiments. This work tests the implementation of MESA model in simulation of nonlinear phase transients of ultrashort pulse propagation in a gaseous medium. The phase transient has been measured through Single-Shot Supercontinuum Spectral Interferometry. This technique can achieve high temporal resolution (10 fs) and spatial resolution (5 mum). Our comparison between simulation and experiment gives a quantitive test of MESA model including post-adiabatic corrections. This is the first time such a comparison was achieved for a theory suitable for large scale numerical simulation of modern nonlinear-optics experiments. In more than one respect, ours is a first-of-a-kind achievement. In particular, • Large amount of data are compared. We compare the data of nonlinear response induced by different pump intensity in Ar and Nitrogen. The data sets are three dimensions including two transverse spacial dimensions and one axial temporal dimension which reflect the whole structure of nonlinear response including the interplay between Kerr and plasma-induced effects. The resolutions of spatial and temporal dimension are about a few micrometer and several femtosecond

  19. Electronic absorption spectra and nonlinear optical properties of ...

    Indian Academy of Sciences (India)


    These materials find numerous device applications, from lasers to optical switches and electronics. 1. So far, the organic π-conjugated molecules have been considered mostly for this pur- pose because of their easy functionalization to fine tune the desired properties and the ease of fabrica- tion and integration into devices.

  20. Nonlinear carrier dynamics in a quantum dash optical amplifier

    DEFF Research Database (Denmark)

    Hansen, Per Lunnemann; Ek, Sara; Yvind, Kresten


    Results of experimental pump-probe spectroscopy of a quantum dash optical amplifier biased at transparency are presented. Using strong pump pulses we observe a competition between free carrier absorption and two-photon induced stimulated emission that can have drastic effects on the transmission...

  1. Comments on: Optical computation based on nonlinear total ...

    Indian Academy of Sciences (India)

    As we read the paper by Jianqi Zhang and Huan Xu, Pramana – J. Phys. 72, 547 (2009), two issues became clear, that warranted writing this comment. First, the switch, which is the main building block of the devices, and which is used to route the signal, does not work as explained in Section 4.1. Accordingly, the optical ...

  2. Determination of structural, spectrometric and nonlinear optical features of 2-(4-hydroxyphenylazo)benzoic acid by experimental techniques and quantum chemical calculations (United States)

    Cinar, Mehmet; Yildiz, Nihat; Karabacak, Mehmet; Kurt, Mustafa


    The optimized geometrical structure, vibrational and electronic transitions, chemical shifts and nonlinear optical properties of 2-(4-hydroxyphenylazo)benzoic acid (HABA) compound were presented in this study. The ground state geometrical structure and vibrational wavenumbers were carried out by using density functional (DFT/B3LYP) method with 6-311++G(d,p) basis set. The vibrational spectra of title compound were recorded in solid state with FT-IR and FT-Raman spectrometry in the range of 4000-400 cm-1 and 4000-10 cm-1; respectively. The fundamental assignments were done on the basis of the recorded spectra and total energy distribution (TED) of the vibrational modes. The 1H and 13C NMR spectra were recorded in deuterated DMSO solution, and gauge-invariant atomic orbitals (GIAOs) method was used to predict the isotropic chemical shifts. The UV-Vis absorption spectra of the compound were observed in the range of 200-800 nm in ethanol, methanol and water solvents. To investigate the nonlinear optical properties, the polarizability, anisotropy of polarizability and molecular first hyperpolarizability were computed. A detailed description of spectroscopic behaviors of compound was given based on the comparison of experimental measurements and theoretical computations.

  3. Nonlinear optics using the multipolar Hamiltonian : The Bloch-Maxwell equations and local fields

    NARCIS (Netherlands)

    Knoester, Jasper; Mukamel, Shaul


    A systematic method for calculating nonlinear-optical susceptibilities in condensed phases, which incorporates intermolecular forces and spontaneous emission in a consistent way, is developed, using the multipolar (µ•D) Hamiltonian. Reduced equations of motion that couple the electromagnetic field

  4. Nonlinear Optical Functions in Crystalline and Amorphous Silicon-on-Insulator Nanowires

    DEFF Research Database (Denmark)

    Baets, R.; Kuyken, B.; Liu, X.


    Silicon-on-Insulator nanowires provide an excellent platform for nonlinear optical functions in spite of the two-photon absorption at telecom wavelengths. Work on both crystalline and amorphous silicon nanowires is reviewed, in the wavelength range of 1.5 to 2.5 µm....

  5. Low-Complexity Tracking of Laser and Nonlinear Phase Noise in WDM Optical Fiber Systems

    DEFF Research Database (Denmark)

    Yankov, Metodi Plamenov; Fehenberger, Tobias; Barletta, Luca


    In this paper, the wavelength division multiplexed (WDM) fiber optic channel is considered. It is shown that for ideal distributed Raman amplification (IDRA), the Wiener process model is suitable for the non-linear phase noise due to cross phase modulation from neighboring channels. Based...

  6. Temporal probabilistic shaping for mitigation of nonlinearities in optical fiber systems

    DEFF Research Database (Denmark)

    Yankov, Metodi Plamenov; Larsen, Knud J.; Forchhammer, Søren


    In this paper, finite state machine sources (FSMSs) are used to shape quadrature amplitude modulation (QAM) for nonlinear transmission in optical fiber communication systems. The previous optimization algorithm for FSMSs is extended to cover an average power constraint, thus enabling temporal...

  7. Imaging of matrix-disorder in normal and pathological human dermis using nonlinear optical microscopy (United States)

    Zhuo, Shuangmu; Chen, Jianxin; Xie, Shusen; Zheng, Liqin; Jiang, Xingshan


    In dermis, collagen and elastin are important structural proteins of extracellular maxtrix. The matrix-disorder is associated with various physiologic processes, such as localized scleroderma, anetoderma, photoaging. In this work, we demonstrate the capability of nonlinear optical microscopy in imaging structural proteins in normal and pathological human dermis.

  8. Guanylurea(1+) hydrogen phosphite: study of linear and nonlinear optical properties

    Czech Academy of Sciences Publication Activity Database

    Fridrichová, M.; Kroupa, Jan; Němec, I.; Císařová, I.; Chvostová, Dagmar


    Roč. 83, 10-11 (2010), s. 761-767 ISSN 0141-1594 R&D Projects: GA ČR GA203/09/0878 Institutional research plan: CEZ:AV0Z10100520 Keywords : non-centrosymmetric * guanylurea * refractive indices * nonlinear optics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.006, year: 2010

  9. Large Optical Nonlinearity of Surface Plasmon Modes on Thin Gold Films

    DEFF Research Database (Denmark)

    Huck, Alexander; Witthaut, Dirk; Kumar, Shailesh


    We investigate the optical nonlinear effects of a long-range surface plasmon polariton mode propagating on a thin gold film. These effects may play a key role in the design of future nanophotonic circuits as they allow for the realization of active plasmonic elements. We demonstrate a significant...

  10. Nonlinear optical response in condensed phases : A microscopic theory using the multipolar Hamiltonian

    NARCIS (Netherlands)

    Knoester, Jasper; Mukamel, Shaul


    A general scheme is presented for calculating the nonlinear optical response in condensed phases that provides a unified picture of excitons, polaritons, retardation, and local-field effects in crystals and in disordered systems. A fully microscopic starting point is taken by considering the

  11. Crystal structure, growth and nonlinear optical studies of isonicotinamide p-nitrophenol: A new organic crystal for optical limiting applications (United States)

    Vijayalakshmi, A.; Vidyavathy, B.; Vinitha, G.


    Isonicotinamide p-nitrophenol (ICPNP), a new organic material, was synthesized using methanol solvent. Single crystals of ICPNP were grown using a slow evaporation solution growth technique. Crystal structure of ICPNP is elucidated by single crystal X-ray diffraction analysis. It belongs to monoclinic crystal system with space group of P21/c. It forms two dimensional networks by O-H…O, N-H…O and C-H…O hydrogen bonds. The molecular structure of ICPNP was further confirmed by Fourier transform infrared (FTIR) spectral analysis. The optical transmittance range and the lower cut-off wavelength (421 nm) with the optical band gap (2.90 eV) of the ICPNP crystal were determined by UV-vis-NIR spectral study. Thermal behavior of ICPNP was studied by thermo gravimetric and differential thermal analyses (TG/DTA). The relative dielectric permittivity was calculated for various temperature ranges. Laser damage threshold of ICPNP crystal was found to be 1.9 GW/cm2 using an Nd:YAG laser. A Z-scan technique was employed to measure the nonlinear absorption coefficient, nonlinear refractive index and nonlinear optical susceptibility. Optical limiting behavior of ICPNP was observed at 35 mW input power.

  12. Local-field enhancement effect on the nonlinear optical response of gold-silver nanoplanets. (United States)

    Cesca, T; Calvelli, P; Battaglin, G; Mazzoldi, P; Mattei, G


    We report on the nonlinear optical properties of Au-Ag nanoplanets produced by ion implantation and irradiation in silica, experimentally investigated by means of the single beam z-scan technique. The measurements provided experimental evidence of the intense local-field enhancement effect theoretically demonstrated for these plasmonic nanosystems. In particular, this has a dramatic impact on their nonlinear absorption behavior and results in a tunable changeover from reverse saturable absorption to saturable absorption by slightly varying the pump intensity and in the possibility to activate and observe nonlinear phenomena of the electron dynamics otherwise unaccessible in the intensity range that can be employed to study these materials. Finally, for the nanoplanet configuration we found a dramatic decrease of the intensity-dependent absorption coefficient, which could be very promising for obtaining optical gain materials.

  13. Nonlinear optical constants of ionic conductors: a study based on the Sheik-Bahae equation

    International Nuclear Information System (INIS)

    Ikeda, Shosuke; Aniya, Masaru


    Guided by the prediction of the bond fluctuation model of superionic conductors, the relation between the nonlinear optical constants and the ion transport properties in ionic conductors has been studied. Since the measured values of nonlinear optical constants in ionic conductors are very limited, they have been evaluated through the Sheik-Bahae equation. Using such values, it is shown that the activation energy of ion transport and the superionic transition temperature decrease with the increase of the nonlinear refractive index. It is also pointed out that the band gap energy and the linear refractive index in superionic conductors are relatively weakly correlated when compared with non-superionic materials. The development of a new field of study that could be called photoionics is suggested (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Third-order nonlinear optical response of colloidal gold nanoparticles prepared by sputtering deposition

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Hemerson P. S.; Alencar, Márcio A. R. C.; Hickmann, Jandir M. [Optics and Materials Group–OPTMA, Universidade Federal de Alagoas, CAIXA POSTAL 2051, 57061-970 Maceió (Brazil); Wender, Heberton [Brazilian Synchrotron National Laboratory (LNLS), CNPEM, Rua Giuseppe Máximo Scolfaro 10.000, 13083-970 Campinas (Brazil); Department of Physics, Universidade Federal do Mato Grosso do Sul, 79070-900, Campo Grande (Brazil); Teixeira, Sergio R. [Institute of Physics, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre (Brazil); Dupont, Jairton [Laboratory of Molecular Catalysis, Institute of Chemistry, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre (Brazil)


    The nonlinear optical responses of gold nanoparticles dispersed in castor oil produced by sputtering deposition were investigated, using the thermally managed Z-scan technique. Particles with spherical shape and 2.6 nm of average diameter were obtained and characterized by transmission electron microscopy and small angle X-ray scattering. This colloid was highly stable, without the presence of chemical impurities, neither stabilizers. It was observed that this system presents a large refractive third-order nonlinear response and a negligible nonlinear absorption. Moreover, the evaluation of the all-optical switching figures of merit demonstrated that the colloidal nanoparticles prepared by sputtering deposition have a good potential for the development of ultrafast photonic devices.

  15. Non-linear optical studies of adsorbates: Spectroscopy and dynamics

    International Nuclear Information System (INIS)

    Zhu, Xiangdong.


    In the first part of this thesis, we have established a systematic procedure to apply the surface optical second-harmonic generation (SHG) technique to study surface dynamics of adsorbates. In particular, we have developed a novel technique for studies of molecular surface diffusions. In this technique, the laser-induced desorption with two interfering laser beams is used to produce a monolayer grating of adsorbates. The monolayer grating is detected with diffractions of optical SHG. By monitoring the first-order second-harmonic diffraction, we can follow the time evolution of the grating modulation from which we are able to deduce the diffusion constant of the adsorbates on the surface. We have successfully applied this technique to investigate the surface diffusion of CO on Ni(111). The unique advantages of this novel technique will enable us to readily study anisotropy of a surface diffusion with variable grating orientation, and to investigate diffusion processes of a large dynamic range with variable grating spacings. In the second part of this work, we demonstrate that optical infrared-visible sum-frequency generation (SFG) from surfaces can be used as a viable surface vibrational spectroscopic technique. We have successfully recorded the first vibrational spectrum of a monolayer of adsorbates using optical infrared-visible SFG. The qualitative and quantitative correlation of optical SFG with infrared absorption and Raman scattering spectroscopies are examined and experimentally demonstrated. We have further investigated the possibility to use transient infrared-visible SFG to probe vibrational transients and ultrafast relaxations on surfaces. 146 refs

  16. Backscattering Properties of Nonspherical Ice Particles Calculated by Geometrical-Optics-Integral-Equation Method

    Directory of Open Access Journals (Sweden)

    Masuda Kazuhiko


    Full Text Available Backscattering properties of ice crystal models (Voronoi aggregates (VA, hexagonal columns (COL, and six-branched bullet rosettes (BR6 are calculated by using geometrical-opticsintegral-equation (GOIE method. Characteristics of depolarization ratio (δ and lidar ratio (L of the crystal models are examined. δ (L values are 0.2~0.3 (4~50, 0.3~0.4 (10~25, and 0.5~0.6 (50~100 for COL, BR6, and VA, respectively, at wavelength λ=0.532 μm. It is found that small deformation of COL model could produce significant changes in δ and L.

  17. Studies of geometrical profiling in fabricated tapered optical fibers using whispering gallery modes spectroscopy (United States)

    Kavungal, Vishnu; Farrell, Gerald; Wu, Qiang; Kumar Mallik, Arun; Semenova, Yuliya


    This paper experimentally demonstrates a method for geometrical profiling of asymmetries in fabricated thin microfiber tapers with waist diameters ranging from ∼10 to ∼50 μm with submicron accuracy. The method is based on the analysis of whispering gallery mode resonances excited in cylindrical fiber resonators as a result of evanescent coupling of light propagating through the fiber taper. The submicron accuracy of the proposed method has been verified by SEM studies. The method can be applied as a quality control tool in fabrication of microfiber based devices and sensors or for fine-tuning of microfiber fabrication set-ups.

  18. Nonlinear optical absorption and stimulated Mie scattering in metallic nanoparticle suspensions. (United States)

    He, Guang S; Law, Wing-Cheung; Baev, Alexander; Liu, Sha; Swihart, Mark T; Prasad, Paras N


    The nonlinear optical properties of four metallic (Au-, Au/Ag-, Ag-, and Pt-) nanoparticle suspensions in toluene have been studied in both femtosecond and nanosecond regimes. Nonlinear transmission measurements in the femtosecond laser regime revealed two-photon absorption (2PA) induced nonlinear attenuation, while in the nanosecond laser regime a stronger nonlinear attenuation is due to both 2PA and 2PA-induced excited-state absorption. In the nanosecond regime, at input pump laser intensities above a certain threshold value, a new type of stimulated (Mie) scattering has been observed. Being essentially different from all other well known molecular (Raman, Brillouin) stimulated scattering effects, the newly observed stimulated Mie scattering from the metallic nanoparticles exhibits the features of no frequency shift and low pump threshold requirement. A physical model of induced Bragg grating initiated by the backward Mie scattering from metallic nanoparticles is proposed to explain the gain mechanism of the observed stimulated scattering effect.

  19. Forward-backward equations for nonlinear propagation in axially invariant optical systems

    International Nuclear Information System (INIS)

    Ferrando, Albert; Zacares, Mario; Fernandez de Cordoba, Pedro; Binosi, Daniele; Montero, Alvaro


    We present a general framework to deal with forward and backward components of the electromagnetic field in axially invariant nonlinear optical systems, which include those having any type of linear or nonlinear transverse inhomogeneities. With a minimum amount of approximations, we obtain a system of two first-order equations for forward and backward components, explicitly showing the nonlinear couplings among them. The modal approach used allows for an effective reduction of the dimensionality of the original problem from 3+1 (three spatial dimensions plus one time dimension) to 1+1 (one spatial dimension plus one frequency dimension). The new equations can be written in a spinor Dirac-like form, out of which conserved quantities can be calculated in an elegant manner. Finally, these equations inherently incorporate spatiotemporal couplings, so that they can be easily particularized to deal with purely temporal or purely spatial effects. Nonlinear forward pulse propagation and nonparaxial evolution of spatial structures are analyzed as examples

  20. Efficient control of ultrafast optical nonlinearity of reduced graphene oxide by infrared reduction

    Energy Technology Data Exchange (ETDEWEB)

    Bhattachraya, S.; Maiti, R.; Das, A. C.; Saha, S.; Mondal, S.; Ray, S. K.; Bhaktha, S. N. B.; Datta, P. K., E-mail: [Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)


    Simultaneous occurrence of saturable absorption nonlinearity and two-photon absorption nonlinearity in the same medium is well sought for the devices like optical limiter and laser mode-locker. Pristine graphene sheet consisting entirely of sp{sup 2}-hybridized carbon atoms has already been identified having large optical nonlinearity. However, graphene oxide (GO), a precursor of graphene having both sp{sup 2} and sp{sup 3}-hybridized carbon atom, is increasingly attracting cross-discipline researchers for its controllable properties by reduction of oxygen containing groups. In this work, GO has been prepared by modified Hummers method, and it has been further reduced by infrared (IR) radiation. Characterization of reduced graphene oxide (RGO) by means of Raman spectroscopy, X-ray photoelectron spectroscopy, and UV-Visible absorption measurements confirms an efficient reduction with infrared radiation. Here, we report precise control of non-linear optical properties of RGO in femtosecond regime with increased degrees of IR reduction measured by open aperture z-scan technique. Depending on the intensity, both saturable absorption and two-photon absorption effects are found to contribute to the non-linearity of all the samples. Saturation dominates at low intensity (∼127 GW/cm{sup 2}) while two-photon absorption becomes prominent at higher intensities (from 217 GW/cm{sup 2} to 302 GW/cm{sup 2}). The values of two-photon absorption co-efficient (∼0.0022–0.0037 cm/GW for GO, and ∼0.0128–0.0143 cm/GW for RGO) and the saturation intensity (∼57 GW/cm{sup 2} for GO, and ∼194 GW/cm{sup 2} for RGO) increase with increasing reduction, indicating GO and RGO as novel tunable photonic devices. We have also explained the reason of tunable nonlinear optical properties by using amorphous carbon model.