G. I. Stegeman

University of Central Florida, Orlando, Florida, United States

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Publications (851)1519.03 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Very few nonlinear optical materials are actually useful for high throughput all-optical devices. However, AlGaAs does satisfy all of the nonlinear optical figures of merit when used with photons of energy less than one half the semiconductor bandgap. Here we review our measurements of the pertinent nonlinear coefficients in waveguides and various device applications to all-optical switching in the communications band around 1550 nm.
    Journal of Nonlinear Optical Physics & Materials 04/2012; 03(03). · 0.48 Impact Factor
  • J. S.aitchison, A.villeneuve, G. I.stegeman
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    ABSTRACT: In this paper we review the progress made in implementing nonlinear directional couplers as potential all-optical switching devices. We will discuss the operation of the coupler and its application as an all-optical multiplexing, demultiplexing element and consider the possibility of integrating more than one nonlinear switching element. The limitation of dispersion and nonlinear absorption will also be addressed.
    Journal of Nonlinear Optical Physics & Materials 01/2012; 04(04). · 0.48 Impact Factor
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    ABSTRACT: The recent theoretical predictions and experimental observations of discrete surface solitons propagating along the interface between a one- or two-dimensional continuous medium and a one- or two-dimensional waveguide array are reviewed. These discrete solitons were found in second order (periodically poled lithium niobate) and third order nonlinear media, including AlGaAs, photorefractive media and glass, respectively.
    Journal of Nonlinear Optical Physics & Materials 01/2012; 16(04). · 0.48 Impact Factor
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    ABSTRACT: The exact formula is derived from the "sum over states" (SOS) quantum mechanical model for the frequency dispersion of the nonlinear refractive index coefficient n₂ for centrosymmetric molecules in the off-resonance and non-resonant regimes. This expression is characterized by interference between terms from two-photon transitions from the ground state to the even-symmetry excited states and one-photon transitions between the ground state and odd-symmetry excited states. When contributions from the two-photon terms exceed those from the one-photon terms, the non-resonant intensity-dependent refractive index n₂>0, and vice versa. Examples of the frequency dispersion for the three-level SOS model are given. Comparison is made with other existing theories.
    Optics Express 11/2011; 19(23):22486-95. · 3.53 Impact Factor
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    ABSTRACT: Using the sum-over-states model for linear symmetric molecules we derive expressions for the frequency dispersion of n_2 of air molecules. The measured sign of non-resonant n_2 shows the recently published extended Miller formula is incorrect.
    Nonlinear Optics: Materials, Fundamentals and Applications; 07/2011
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    ABSTRACT: Spatial solitons are beams which do not diffract on propagation in a material due to the presence of some optical nonlinearity. Their properties were first documented by John Scott Russell when he reported his observations on non-spreading water waves which consisted of a single “hump” propagating in a canal in Scotland.[l] In the very early days of nonlinear optics, interest was quickly evoked by what were then called “self-focused filaments”, initiated by observations of self-focusing of powerful lasers in optical media, frequently leading to stable filaments or even material damage. [2,3] However it was not until the late 1990s that systematic experimental research into spatial solitons was initiated. [4] Since then there has been a surge of activity and many new solitons have been observed. [5–16]
    07/2011: pages 133-161;
  • Katia Gallo, Gaetano Assanto, George I. Stegeman
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    ABSTRACT: A widespread interest in all-optical networks for telecommunications has generated a great deal of activity towards approaches for efficient channel shifting in systems based on wavelength-division-multiplexing (WDM). A key issue, namely the possibility of transferring an incoming stream of data from a given channel or wavelength to another, has been addressed using several techniques ranging from gain saturation in semiconductor amplifiers [1] to four-wave-mixing [2] to parametric generation [3]. Since available bandwidth, transparence to the modulation format, possibility of gain and amount of crosstalk are important characteristics of such a wavelength shifter, parametric processes are considered rather appealing. With the advances in periodically poled crystals for efficient second-harmonic-generation (SHG) and difference frequency generation (DFG) [4], a quadratic approach in guided-wave configurations appears quite affordable in terms of required powers.
    07/2011: pages 185-188;
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    ABSTRACT: Improved methods for the growth and polymerization of single crystals of polydiacetylene PTS, poly bis(p-toluene sulfonate) of 2,4-hexadiyne-1,6-diol, have allowed new optical measurements to be made. The absorption spectrum, and typical Z-scans for measuring the optical nonlinearity up to fourth order are described.
    07/2011: pages 31-38;
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    Advances in Glass and Optical Materials II: Ceramic Transactions Series, Volume 197, 06/2011: pages 63 - 81; , ISBN: 9781118144138
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    ABSTRACT: The recent interpretation of experiments on the nonlinear non-resonant birefringence induced in a weak probe beam by a high intensity pump beam in air and its constituents has stimulated interest in the non-resonant birefringence due to higher-order Kerr nonlinearities. Here a simple formalism is invoked to determine the non-resonant birefringence for higher-order Kerr coefficients. Some general relations between nonlinear coefficients with arbitrary frequency inputs are also derived for isotropic media. It is shown that the previous linear extrapolations for higher-order birefringence (based on literature values of n2 and n4) are not strictly valid, although the errors introduced in the values of the reported higher- order Kerr coefficients are a few percent.
    Optics Express 03/2011; 19(7):6387-99. · 3.53 Impact Factor
  • MRS Online Proceeding Library 01/2011; 160.
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    ABSTRACT: We provide an in-depth treatment of the various mechanisms by which an inci-dent light beam can produce an intensity-or flux-dependent change in the re-fractive index and absorption coefficient of different materials. Whenever pos-sible, the mechanisms are initially traced to single-atom and -molecule effects in order to provide physical understanding. Representative values are given for the various mechanisms. Nine different mechanisms are discussed, starting with the Kerr effect due to atoms and/or molecules with discrete states, includ-ing organic materials such as molecules and conjugated polymers. Simplified two and/or three-level models provide useful information, and these are sum-marized. The nonlinear optics of semiconductors is reviewed for both bulk and quantum-confined semiconductors, focusing on the most common types II–VI and III–V. Also discussed in some detail are the different nonlinear mechanisms that occur in liquid crystals and photorefractive media. Additional nonlinear material systems and mechanisms such as glasses, molecular reorientation of single molecules, the electrostrictive effect, the nuclear effect (vibrational con-tributions), cascading, and the ever-present thermal effects are quantified, and representative tables of values are given.
    Advances in Optics and Photonics 03/2010; 2(1). · 9.69 Impact Factor
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    George I. Stegeman, Honghua Hu
    Photonics Letters of Poland. 12/2009; 1(4).
  • George Stegeman, Demetrios Christodoulides
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    ABSTRACT: Discrete optics opens up new opportunities in manipulating light flow. We provide an overview of recent experimental and theoretical developments in this area. The effects of discreteness on linear and nonlinear optical interactions are discussed.
    Conference on Lasers and Electro-Optics; 05/2009
  • D. N. Christodoulides, G. I. Stegeman
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    ABSTRACT: Discrete optics opens up new opportunities in manipulating light flow. We provide an overview of recent experimental and theoretical developments in this area. The effects of discreteness on linear and nonlinear optical interactions are discussed.
    01/2009;
  • Miroslaw A. Karpierz, George I. Stegeman
    Photonics Letters of Poland. 01/2009; 1(4).
  • Conference Paper: Lattice Surface Solitons
    Demetrios N. Christodoulides, George I. Stegeman
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    ABSTRACT: We provide an overview of recent experimental and theoretical developments in the area of discrete surface solitons.
    Frontiers in Optics; 10/2008
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    ABSTRACT: Discrete spatial solitons traveling along the interface between two dissimilar one-dimensional arrays of waveguides were observed for the first time. Two interface solitons were found theoretically, each one with a peak in a different boundary channel. One evolves into a soliton from a linear mode at an array separation larger than a critical separation where-as the second soliton always exhibits a power threshold. These solitons exhibited different power thresholds which depended on the characteristics of the two lattices. For excitation of single channels near and at the boundary, the evolution behavior with propagation distance indicates that the solitons peaked near and at the interface experience an attractive potential on one side of the boundary, and a repulsive one on the opposite side. The power dependence of the solitons at variable distance from the boundary was found to be quite different on opposite sides of the interface and showed evidence for soliton switching between channels with increasing input power.
    Optics Express 08/2008; 16(14):10480-92. · 3.53 Impact Factor
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    ABSTRACT: Soliton switching in nonlinear directional couplers implemented in photonic crystal fibers (PCF) examined here. A vector finite element method (FEM) has been developed to precisely calculate the dispersion along with coupling length of the guided modes. The PCF coupler geometry was carefully designed so that it can support soliton pulses. Soliton switching is demonstrated numerically at 1.55 microm for 100 femto-second (fs) pulses. Our theoretical results explain some of the key spectral features previously observed in the experiment.
    Optics Express 07/2008; 16(13):9417-28. · 3.53 Impact Factor
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    ABSTRACT: We provide an overview of recent experimental and theoretical developments in the area of optical discrete solitons. By nature, discrete solitons represent self-trapped wavepackets in nonlinear periodic structures and result from the interplay between lattice diffraction (or dispersion) and material nonlinearity. In optics, this class of self-localized states has been successfully observed in both one- and two-dimensional nonlinear waveguide arrays. In recent years such photonic lattices have been implemented or induced in a variety of material systems, including those with cubic (Kerr), quadratic, photorefractive, and liquid-crystal nonlinearities. In all cases the underlying periodicity or discreteness leads to altogether new families of optical solitons that have no counterpart whatsoever in continuous systems. We first review the linear properties of photonic lattices that are key in the understanding of discrete solitons. The physics and dynamics of the fundamental discrete and gap solitons are then analyzed along with those of many other exotic classes — e.g. twisted, vector and multi-band, cavity, spatio-temporal, random-phase, vortex, and non-local lattice solitons, just to mention a few. The possibility of all-optically routing optical discrete solitons in 2D and 3D periodic environments using soliton collisions is also presented. Finally, soliton formation in optical quasi-crystals and at the boundaries of waveguide array structures are discussed.
    Physics Reports 07/2008; 463(1):1-126. · 22.91 Impact Factor

Publication Stats

13k Citations
1,519.03 Total Impact Points

Institutions

  • 1992–2012
    • University of Central Florida
      • • Center for Research and Education in Optics and Lasers
      • • CREOL College of Optics & Photonics
      Orlando, Florida, United States
  • 2011
    • Foundation for Research and Technology - Hellas
      • Institute of Electronic Structure and Laser (IESL)
      Megalokastro, Crete, Greece
    • King Fahd University of Petroleum and Minerals
      Az̧ Z̧ahrān, Eastern Province, Saudi Arabia
  • 2007
    • Nankai University
      • Applied Physics School (APS)
      T’ien-ching-shih, Tianjin Shi, China
    • San Francisco State University
      • Department of Physics and Astronomy
      San Francisco, CA, United States
  • 1987–2006
    • University of Glasgow
      • Division of Electronics and Electrical Engineering
      Glasgow, SCT, United Kingdom
    • University of Salford
      • Department of Physics
      Salford, ENG, United Kingdom
  • 2005
    • Weizmann Institute of Science
      • Department of Physics of Complex Systems
      Tel Aviv, Tel Aviv, Israel
  • 2004
    • Universität Regensburg
      Ratisbon, Bavaria, Germany
  • 2003
    • Friedrich-Schiller-University Jena
      Jena, Thuringia, Germany
    • ICFO Institute of Photonic Sciences
      Barcino, Catalonia, Spain
  • 1998–2003
    • Universität Paderborn
      • Department of Physics
      Paderborn, North Rhine-Westphalia, Germany
    • Johns Hopkins University
      • Department of Electrical and Computer Engineering
      Baltimore, MD, United States
  • 1974–2001
    • University of Toronto
      • Department of Physics
      Toronto, Ontario, Canada
  • 2000
    • The University of Tokushima
      Tokusima, Tokushima, Japan
  • 1981–1998
    • The University of Arizona
      • Department of Materials Sciences and Engineering
      Tucson, Arizona, United States
  • 1995–1996
    • Laval University
      Québec, Quebec, Canada
    • Polytechnic University of Catalonia
      • Department of Signal Theory and Communications (TSC)
      Barcelona, Catalonia, Spain
  • 1993–1994
    • Pennsylvania State University
      • Department of Electrical Engineering
      University Park, MD, United States
  • 1990
    • CSU Mentor
      Long Beach, California, United States
  • 1989
    • Brown University
      • School of Engineering
      Providence, RI, United States
    • University of Camerino
      Camerino, The Marches, Italy
  • 1986–1989
    • Fondazione Ugo Bordoni
      Roma, Latium, Italy
  • 1988
    • University at Buffalo, The State University of New York
      • Department of Chemistry
      Buffalo, NY, United States
  • 1986–1987
    • Heriot-Watt University
      • Department of Physics
      Edinburgh, SCT, United Kingdom
  • 1981–1985
    • University of California, Irvine
      • Department of Physics and Astronomy
      Irvine, California, United States
  • 1982
    • National Research Council Canada
      Ottawa, Ontario, Canada
  • 1978
    • Xerox Research Center Webster
      Webster, New York, United States