He is currently an honorary professor in compute He is currently an honorary professor in computer science at The University of Hong Kong after retiring from his full professorship in July He is the director of The Software Engineering Group, funded by research grants of 15 million dollars to date. He has been recognized internationally as the pioneer in integrating formal and practical methods in software engineering.
November 4, The application of topology, the mathematics studying conserved properties through continuous deformations, is creating new opportunities within photonics, bringing with it theoretical discoveries and a wealth of potential applications. This field was inspired by the discovery of topological insulators, in which interfacial electrons transport without dissipation even in the presence of impurities.
Similarly, the use of carefully-designed wave-vector space topologies allows the creation of interfaces that support new states of light with useful and interesting properties. In particular, it suggests the realization of unidirectional waveguides that allow light to flow around large imperfections without back-reflection.
The present review explains the underlying principles and highlights how topological effects can be realized in photonic crystals, coupled resonators, metamaterials and quasicrystals. Frequency, wavevector, polarization and phase are degrees of freedom that are often used to describe a photonic system.
In the last few years, topology —a property of a photonic material that characterizes the quantized global behavior of the wavefunctions on its entire dispersion band— has been emerging as another indispensable ingredient, opening a path forward to the discovery of fundamentally new states of light and possibly revolutionary applications.
Possible practical applications of topological photonics include photonic circuitry less dependent on isolators and slow light insensitive to disorder. Topological ideas in photonics branch from exciting developments in solid-state materials, along with the discovery of new phases of matter called topological insulators [1, 2].
Topological insulators, being insulating in their bulk, conduct electricity on their surfaces without dissipation or backscattering, even in the presence of large impurities.
The first example was the integer quantum Hall effect, discovered in In quantum Hall states, two-dimensional 2D electrons in a uniform magnetic field form quantized cyclotron orbits of discrete eigenvalues called Landau levels.
When the electron energy sits within the energy gap between the Landau levels, the measured edge conductance remains constant within the accuracy of about one part in a billion, regardless of sample details like size, composition and impurity levels.
InHaldane proposed a theoretical model to achieve the same phenomenon but in a periodic system without Landau levels , the so-called quantum anomalous Hall effect.
Posted on arXiv inHaldane and Raghu transcribed the key feature of this electronic model into photonics [4, 5]. They theoretically proposed the photonic analogue of the quantum anomalous Hall effect in photonic crystals , the periodic variation of optical materials, molding photons the same way as solids modulating electrons.
Three years later, the idea was confirmed by Wang et al. Those studies spurred numerous subsequent theoretical [9—13] and experimental investigations [14—16]. The works cited above demonstrated unidirectional edge waveguides transmit electromagnetic waves without back-reflection even in the presence of arbitrarily large disorder: Topological photonics promises to offer unique, robust designs and new device functionalities to photonic systems by providing immunity to performance degradation induced by fabrication imperfections or environmental changes.
In this review, we present the key concepts, experiments, and proposals in the field of topological photonics. Starting with an introduction to the relevant topological concepts, we introduce the 2D quantum Hall phase through the stability of Dirac cones [4, 5], followed by its realizations in gyromagnetic photonic crystals [7, 8, 13], in coupled resonators [9, 10, 16] and waveguides , in bianisotropic metamaterials  and in quasicrystals .
We then extend our discussions to three dimensions, wherein we describe the stability of line nodes and Weyl points and their associated surface states . We conclude by considering the outlook for further theoretical and technological advances.
For example, the six objects in Fig. The yellow sphere can be continuously deformed into the white spoon, so they are topologically equivalent. The torus and coffee cup are also topologically equivalent, and so too are the double torus and tea pot.
Different topologies can be mathematically characterized by integers called topological invariants, quantities that remain the same under arbitrary continuous deformations of the system.
For the above closed surfaces, the topological invariant is the genus, and it corresponds to the number of holes within a closed surface.
Objects having the same topological invariant are topologically equivalent: Only when a hole is created or removed in the object does the topological invariant change.
This process is a topological phase transition. Material-systems in photonics have topologies, defined on 2 Ordinary waveguide b Topologically-protected waveguide y air, metal, Trivial Bragg mirror reflectorsWang-Kong Tse of University of Alabama, Alabama (UA) with expertise in: Condensed Matter Physics, Materials Physics and Theoretical Physics.
Contact Wang-Kong Tse, read 59 publications, and see. Essay Service schwenkreis.com Gene silencing rna interference; Streetcar named desire compare with view from the bridge. blank) September Master's Thesis (Final) 4. TITLE AND SUBTITLE APPLICATION OF LOGISTIC 5.
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PERFORMING Naval Postgraduate School .
Graduate Advising. Overview. MS in physics with astronomy specialization (thesis option) MS in physics with astronomy specialization (non-thesis option) MS in physics (thesis option) UA’s Wang-Kong Tse awarded DOE Early Career Grant for non-equilibrium materials;.
I am experienced with machine learning for signal processing, especially for speech recognition and speech enhancement. The solid background of digital signal processing provides me the flexibilities to handle other multi-dimensional signals, e.g.
time-series, image, video, biological signals. Wang-Kong Tse of University of Alabama, Alabama (UA) with expertise in: Condensed Matter Physics, Materials Physics and Theoretical Physics.
Read 61 publications, and contact Wang-Kong Tse on.