Artículos de revistas: "Disordered photonic systems"

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Sgrignuoli, Fabrizio, Giacomo Mazzamuto, Niccolò Caselli, Francesca Intonti, Francesco Saverio Cataliotti, Massimo Gurioli y Costanza Toninelli. "Necklace State Hallmark in Disordered 2D Photonic Systems". ACS Photonics 2, n.º 11 (28 de octubre de 2015): 1636–43. http://dx.doi.org/10.1021/acsphotonics.5b00422.

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Wang, Hongfei, Xiujuan Zhang, Jinguo Hua, Dangyuan Lei, Minghui Lu y Yanfeng Chen. "Topological physics of non-Hermitian optics and photonics: a review". Journal of Optics 23, n.º 12 (25 de octubre de 2021): 123001. http://dx.doi.org/10.1088/2040-8986/ac2e15.

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Abstract The notion of non-Hermitian optics and photonics rooted in quantum mechanics and photonic systems has recently attracted considerable attention ushering in tremendous progress on theoretical foundations and photonic applications, benefiting from the flexibility of photonic platforms. In this review, we first introduce the non-Hermitian topological physics from the symmetry of matrices and complex energy spectra to the characteristics of Jordan normal forms, exceptional points, biorthogonal eigenvectors, Bloch/non-Bloch band theories, topological invariants and topological classifications. We further review diverse non-Hermitian system branches ranging from classical optics, quantum photonics to disordered systems, nonlinear dynamics and optomechanics according to various physical equivalences and experimental implementations. In particular, we include cold atoms in optical lattices in quantum photonics due to their operability at quantum regimes. Finally, we summarize recent progress and limitations in this emerging field, giving an outlook on possible future research directions in theoretical frameworks and engineering aspects.

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Granchi, Nicoletta, Richard Spalding, Kris Stokkereit, Matteo Lodde, Andrea Fiore, Riccardo Sapienza, Francesca Intonti, Marian Florescu y Massimo Gurioli. "Engineering high Q/V photonic modes in correlated disordered systems". EPJ Web of Conferences 266 (2022): 05005. http://dx.doi.org/10.1051/epjconf/202226605005.

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Hyperuniform disordered (HuD) photonic materials have recently been shown to display several localized states with relatively high Q factors. However, their spatial position is not predictable a priori. Here we experimentally benchmark through near-field spectroscopy the engineering of high Q/V resonant modes in a defect inside a HuD pattern. These deterministic modes, coexisting with Anderson-localized modes, are a valid candidate for implementations in optoelectronic devices due to the spatial isotropy of the HuD environment upon which they are built.

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DeGottardi, Wade y Mohammad Hafezi. "Stability of fractional quantum Hall states in disordered photonic systems". New Journal of Physics 19, n.º 11 (14 de noviembre de 2017): 115004. http://dx.doi.org/10.1088/1367-2630/aa89a5.

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Caselli, Niccolò, Francesca Intonti, Federico La China, Francesco Biccari, Francesco Riboli, Annamaria Gerardino, Lianhe Li et al. "Near-field speckle imaging of light localization in disordered photonic systems". Applied Physics Letters 110, n.º 8 (20 de febrero de 2017): 081102. http://dx.doi.org/10.1063/1.4976747.

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Wang, Guang-Lei, Hong-Ya Xu y Ying-Cheng Lai. "Can a photonic thermalization gap arise in disordered non-Hermitian Hamiltonian systems?" EPL (Europhysics Letters) 125, n.º 3 (26 de febrero de 2019): 30003. http://dx.doi.org/10.1209/0295-5075/125/30003.

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Sarma, Raktim, Abigail Pribisova, Bjorn Sumner y Jayson Briscoe. "Classification of Intensity Distributions of Transmission Eigenchannels of Disordered Nanophotonic Structures Using Machine Learning". Applied Sciences 12, n.º 13 (30 de junio de 2022): 6642. http://dx.doi.org/10.3390/app12136642.

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Light-matter interaction optimization in complex nanophotonic structures is a critical step towards the tailored performance of photonic devices. The increasing complexity of such systems requires new optimization strategies beyond intuitive methods. For example, in disordered photonic structures, the spatial distribution of energy densities has large random fluctuations due to the interference of multiply scattered electromagnetic waves, even though the statistically averaged spatial profiles of the transmission eigenchannels are universal. Classification of these eigenchannels for a single configuration based on visualization of intensity distributions is difficult. However, successful classification could provide vital information about disordered nanophotonic structures. Emerging methods in machine learning have enabled new investigations into optimized photonic structures. In this work, we combine intensity distributions of the transmission eigenchannels and the transmitted speckle-like intensity patterns to classify the eigenchannels of a single configuration of disordered photonic structures using machine learning techniques. Specifically, we leverage supervised learning methods, such as decision trees and fully connected neural networks, to achieve classification of these transmission eigenchannels based on their intensity distributions with an accuracy greater than 99%, even with a dataset including photonic devices of various disorder strengths. Simultaneous classification of the transmission eigenchannels and the relative disorder strength of the nanophotonic structure is also possible. Our results open new directions for machine learning assisted speckle-based metrology and demonstrate a novel approach to classifying nanophotonic structures based on their electromagnetic field distributions. These insights can be of paramount importance for optimizing light-matter interactions at the nanoscale.

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Ricouvier, Joshua, Patrick Tabeling y Pavel Yazhgur. "Foam as a self-assembling amorphous photonic band gap material". Proceedings of the National Academy of Sciences 116, n.º 19 (24 de abril de 2019): 9202–7. http://dx.doi.org/10.1073/pnas.1820526116.

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We show that slightly polydisperse disordered 2D foams can be used as a self-assembled template for isotropic photonic band gap (PBG) materials for transverse electric (TE) polarization. Calculations based on in-house experimental and simulated foam structures demonstrate that, at sufficient refractive index contrast, a dry foam organization with threefold nodes and long slender Plateau borders is especially advantageous to open a large PBG. A transition from dry to wet foam structure rapidly closes the PBG mainly by formation of bigger fourfold nodes, filling the PBG with defect modes. By tuning the foam area fraction, we find an optimal quantity of dielectric material, which maximizes the PBG in experimental systems. The obtained results have a potential to be extended to 3D foams to produce a next generation of self-assembled disordered PBG materials, enabling fabrication of cheap and scalable photonic devices.

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Bin Tarik, Farhan, Azadeh Famili, Yingjie Lao y Judson D. Ryckman. "Robust optical physical unclonable function using disordered photonic integrated circuits". Nanophotonics 9, n.º 9 (3 de julio de 2020): 2817–28. http://dx.doi.org/10.1515/nanoph-2020-0049.

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AbstractPhysical unclonable function (PUF) has emerged as a promising and important security primitive for use in modern systems and devices, due to their increasingly embedded, distributed, unsupervised, and physically exposed nature. However, optical PUFs based on speckle patterns, chaos, or ‘strong’ disorder are so far notoriously sensitive to probing and/or environmental variations. Here we report an optical PUF designed for robustness against fluctuations in optical angular/spatial alignment, polarization, and temperature. This is achieved using an integrated quasicrystal interferometer (QCI) which sensitively probes disorder while: (1) ensuring all modes are engineered to exhibit approximately the same confinement factor in the predominant thermo-optic medium (e. g. silicon), and (2) constraining the transverse spatial-mode and polarization degrees of freedom. This demonstration unveils a new means for amplifying and harnessing the effects of ‘weak’ disorder in photonics and is an important and enabling step toward new generations of optics-enabled hardware and information security devices.

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Wang, Michelle, Cooper Doyle, Bryn Bell, Matthew J. Collins, Eric Magi, Benjamin J. Eggleton, Mordechai Segev y Andrea Blanco-Redondo. "Topologically protected entangled photonic states". Nanophotonics 8, n.º 8 (9 de mayo de 2019): 1327–35. http://dx.doi.org/10.1515/nanoph-2019-0058.

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AbstractEntangled multiphoton states lie at the heart of quantum information, computing, and communications. In recent years, topology has risen as a new avenue to robustly transport quantum states in the presence of fabrication defects, disorder, and other noise sources. Whereas topological protection of single photons and correlated photons has been recently demonstrated experimentally, the observation of topologically protected entangled states has thus far remained elusive. Here, we experimentally demonstrate the topological protection of spatially entangled biphoton states. We observe robustness in crucial features of the topological biphoton correlation map in the presence of deliberately introduced disorder in the silicon nanophotonic structure, in contrast with the lack of robustness in non-topological structures. The topological protection is shown to ensure the coherent propagation of the entangled topological modes, which may lead to robust propagation of quantum information in disordered systems.

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Jacucci, Gianni, Silvia Vignolini y Lukas Schertel. "The limitations of extending nature’s color palette in correlated, disordered systems". Proceedings of the National Academy of Sciences 117, n.º 38 (8 de septiembre de 2020): 23345–49. http://dx.doi.org/10.1073/pnas.2010486117.

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Living organisms have developed a wide range of appearances from iridescent to matte textures. Interestingly, angular-independent structural colors, where isotropy in the scattering structure is present, only produce coloration in the blue wavelength region of the visible spectrum. One might, therefore, wonder if such observation is a limitation of the architecture of the palette of materials available in nature. Here, by exploiting numerical modeling, we discuss the origin of isotropic structural colors without restriction to a specific light scattering regime. We show that high color purity and color saturation cannot be reached in isotropic short-range order structures for red hues. This conclusion holds even in the case of advanced scatterer morphologies, such as core-shell particles or inverse photonic glasses—explaining recent experimental findings reporting very poor performances of visual appearance for such systems.

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DE LUCA, A., V. BARNA, S. FERJANI, R. CAPUTO, C. VERSACE, N. SCARAMUZZA, R. BARTOLINO, C. UMETON y G. STRANGI. "LASER ACTION IN DYE DOPED LIQUID CRYSTALS: FROM PERIODIC STRUCTURES TO RANDOM MEDIA". Journal of Nonlinear Optical Physics & Materials 18, n.º 03 (septiembre de 2009): 349–65. http://dx.doi.org/10.1142/s0218863509004725.

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The birefringence and natural ability to form periodic structures make cholesteric liquid crystalline (CLC — chiral nematics) materials particularly attractive as 1D photonic band gap systems. If a CLC is doped with dye fluorescent molecules, in such a way that the maximum peak of fluorescence matches one of the edges of the selective stop band, laser action is expected at that spectral position. By confining the helical super-structure of chiral liquid crystals in polymeric micro-cavity channels, a tunable microcavity laser array was achieved. In multiple scattering systems, the propagation of the light waves is quite different, as optical scattering may induce a phase transition in the photon transport behavior. Beyond a critical scattering level, the system makes a transition into a strongly localized state and light transmission is inhibited. This effect can be used as a photon trapping mechanism to obtain laser action in the presence of a gain medium. Random lasing modes come from interference effects which survive in disordered systems and open a particular chapter in the study of the interplay between localization and amplification. Here, experiments performed on systems having different order degree and confinement are presented and possible technological implications are discussed.

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Pradeesh, K., Nageswara Rao Kotla, Shahab Ahmad, Vindesh K. Dwivedi y G. Vijaya Prakash. "Naturally Self-Assembled Nanosystems and Their Templated Structures for Photonic Applications". Journal of Nanoparticles 2013 (20 de marzo de 2013): 1–13. http://dx.doi.org/10.1155/2013/531871.

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Self-assembly has the advantage of fabricating structures of complex functionalities, from molecular levels to as big as macroscopic levels. Natural self-assembly involves self-aggregation of one or more materials (organic and/or inorganic) into desired structures while templated self-assembly involves interstitial space filling of diverse nature entities into self-assembled ordered/disordered templates (both from molecular to macro levels). These artificial and engineered new-generation materials offer many advantages over their individual counterparts. This paper reviews and explores the advantages of such naturally self-assembled hybrid molecular level systems and template-assisted macro-/microstructures targeting simple and low-cost device-oriented fabrication techniques, structural flexibility, and a wide range of photonic applications.

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Houdré, R., C. Weisbuch, R. P. Stanley, U. Oesterle y M. Ilegems. "Coherence effects in light scattering of two-dimensional photonic disordered systems: Elastic scattering of cavity polaritons". Physical Review B 61, n.º 20 (15 de mayo de 2000): R13333—R13336. http://dx.doi.org/10.1103/physrevb.61.r13333.

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Hayran, Zeki, Seyyed Ali Hassani Gangaraj y Francesco Monticone. "Topologically protected broadband rerouting of propagating waves around complex objects". Nanophotonics 8, n.º 8 (9 de mayo de 2019): 1371–78. http://dx.doi.org/10.1515/nanoph-2019-0075.

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AbstractAchieving robust propagation and guiding of electromagnetic waves through complex and disordered structures is a major goal of modern photonics research, for both classical and quantum applications. Although the realization of backscattering-free and disorder-immune guided waves has recently become possible through various photonic schemes inspired by topological insulators in condensed matter physics, the interaction between such topologically protected guided waves and free-space propagating waves remains mostly unexplored, especially in the context of scattering systems. Here, we theoretically demonstrate that free-space propagating plane waves can be efficiently coupled into topological one-way surface waves, which can seamlessly flow around sharp corners and electrically large barriers and release their energy back into free space in the form of leaky-wave radiation. We exploit this physical mechanism to realize topologically protected wave-rerouting around an electrically large impenetrable object of complex shape, with transmission efficiency exceeding 90%, over a relatively broad bandwidth. The proposed topological wave-rerouting scheme is based on a stratified structure composed of a topologically nontrivial magnetized plasmonic material coated by a suitable isotropic layer. Our results may open a new avenue in the field of topological photonics and electromagnetics, for applications that require engineered interactions between guided waves and free-space propagating waves, including for complex beam-routing systems and advanced stealth technology. More generally, our work may pave the way for robust defect/damage-immune scattering and radiating systems.

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Sun, Yanwen, Vincent Esposito, Philip Adam Hart, Conny Hansson, Haoyuan Li, Kazutaka Nakahara, James Paton MacArthur et al. "A Contrast Calibration Protocol for X-ray Speckle Visibility Spectroscopy". Applied Sciences 11, n.º 21 (27 de octubre de 2021): 10041. http://dx.doi.org/10.3390/app112110041.

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X-ray free electron lasers, with their ultrashort highly coherent pulses, opened up the opportunity of probing ultrafast nano- and atomic-scale dynamics in amorphous and disordered material systems via speckle visibility spectroscopy. However, the anticipated count rate in a typical experiment is usually low. Therefore, visibility needs to be extracted via photon statistics analysis, i.e., by estimating the probabilities of multiple photons per pixel events using pixelated detectors. Considering the realistic X-ray detector responses including charge cloud sharing between pixels, pixel readout noise, and gain non-uniformity, speckle visibility extraction relying on photon assignment algorithms are often computationally demanding and suffer from systematic errors. In this paper, we present a systematic study of the commonly-used algorithms by applying them to an experimental data set containing small-angle coherent scattering with visibility levels ranging from below 1% to ∼60%. We also propose a contrast calibration protocol and show that a computationally lightweight algorithm can be implemented for high-speed correlation evaluation.

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Lin, Ronghui, Valerio Mazzone, Nasir Alfaraj, Jianping Liu, Xiaohang Li y Andrea Fratalocchi. "On‐Chip Disordered Lasers: On‐Chip Hyperuniform Lasers for Controllable Transitions in Disordered Systems (Laser Photonics Rev. 14(2)/2020)". Laser & Photonics Reviews 14, n.º 2 (febrero de 2020): 2070017. http://dx.doi.org/10.1002/lpor.202070017.

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Goussev, Arseni, Rodolfo A. Jalabert, Horacio M. Pastawski y Diego A. Wisniacki. "Loschmidt echo and time reversal in complex systems". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 374, n.º 2069 (13 de junio de 2016): 20150383. http://dx.doi.org/10.1098/rsta.2015.0383.

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Echoes are ubiquitous phenomena in several branches of physics, ranging from acoustics, optics, condensed matter and cold atoms to geophysics. They are at the base of a number of very useful experimental techniques, such as nuclear magnetic resonance, photon echo and time-reversal mirrors. Particularly interesting physical effects are obtained when the echo studies are performed on complex systems, either classically chaotic, disordered or many-body. Consequently, the term Loschmidt echo has been coined to designate and quantify the revival occurring when an imperfect time-reversal procedure is applied to a complex quantum system, or equivalently to characterize the stability of quantum evolution in the presence of perturbations. Here, we present the articles which discuss the work that has shaped the field in the past few years.

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YUKALOV, V. I. "PROPERTIES OF SOLIDS WITH PORES AND CRACKS". International Journal of Modern Physics B 03, n.º 02 (febrero de 1989): 311–26. http://dx.doi.org/10.1142/s0217979289000245.

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A model of solids with pores and cracks or other regions of disorder is constructed. Stability conditions for such a solid are considered in the case of an effective attraction between particles and without external fields. The possibility of the appearance of the phonon-photon superradiance in the ensemble of charged cracks is discussed. The relative variation of the Mössbauer-effect probability for partially disordered systems, compared with completely ordered ones, is calculated and found to be in a very good agreement with experimental results.

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Thouless, David. "ANDERSON LOCALIZATION IN THE SEVENTIES AND BEYOND". International Journal of Modern Physics B 24, n.º 12n13 (20 de mayo de 2010): 1507–25. http://dx.doi.org/10.1142/s0217979210064496.

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Little attention was paid to Anderson's challenging paper on localization for the first ten years, but from 1968 onwards it generated a lot of interest. Around that time a number of important questions were raised by the community, on matters such as the existence of a sharp distinction between localized and extended states, or between conductors and insulators. For some of these questions the answers are unambiguous. There certainly are energy ranges in which states are exponentially localized, in the presence of a static disordered potential. In a weakly disordered one-dimensional potential, all states are localized. There is clear evidence, in three dimensions, for energy ranges in which states are extended, and ranges in which they are diffusive. Magnetic and spin-dependent interactions play an important part in reducing localization effects. For massive particles like electrons and atoms the lowest energy states are localized, but for massless particles like photons and acoustic phonons the lowest energy states are extended. Uncertainties remain. Scaling theory suggests that in two-dimensional systems all states are weakly localized, and that there is no minimum metallic conductivity. The interplay between disorder and mutual interactions is still an area of uncertainty, which is very important for electronic systems. Optical and dilute atomic systems provide experimental tests which allow interaction to be much less important. The quantum Hall effect provided a system where states on the Fermi surface are localized, but non-dissipative currents flow in response to an electric field.

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Cordella, Gianfranco, Antonio Tripodo, Francesco Puosi, Dario Pisignano y Dino Leporini. "Nanoscale Elastoplastic Wrinkling of Ultrathin Molecular Films". International Journal of Molecular Sciences 22, n.º 21 (29 de octubre de 2021): 11732. http://dx.doi.org/10.3390/ijms222111732.

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Ultrathin molecular films deposited on a substrate are ubiquitously used in electronics, photonics, and additive manufacturing methods. The nanoscale surface instability of these systems under uniaxial compression is investigated here by molecular dynamics simulations. We focus on deviations from the homogeneous macroscopic behavior due to the discrete, disordered nature of the deformed system, which might have critical importance for applications. The instability, which develops in the elastoplastic regime above a finite critical strain, leads to the growth of unidimensional wrinkling up to strains as large as 0.5. We highlight both the dominant wavelength and the amplitude of the wavy structure. The wavelength is found to scale geometrically with the film length, λ∝L, up to a compressive strain of ε≃0.4 at least, depending on the film length. The onset and growth of the wrinkling under small compression are quite well described by an extended version of the familiar square-root law in the strain ε observed in macroscopic systems. Under large compression (ε≳0.25), we find that the wrinkling amplitude increases while leaving the cross section nearly constant, offering a novel interpretation of the instability with a large amplitude. The contour length of the film topography is not constant under compression, which is in disagreement with the simple accordion model. These findings might be highly relevant for the design of novel and effective wrinkling and buckling patterns and architectures in flexible platforms for electronics and photonics.

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Titova, Nadezhda A., Nina A. Tovpeko, Anna I. Kardakova y Gregory N. Goltsman. "Promising Superconducting Materials for Highly Sensitive Detectors of the Infrared and Terahertz Ranges". Vestnik RFFI, n.º 3 (31 de julio de 2019): 46–58. http://dx.doi.org/10.22204/2410-4639-2019-103-03-46-58.

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Modern technologies of photonics, astrophysics, medicine and security systems have a demand for development of new types of sensitive detectors and/or optimization of existing ones. As an example, a strong demand exists for improvement of the characteristics of highly sensitive detectors based on superconducting materials. One way to optimize the performance of such detectors is to select a suitable superconducting material. This is due to the fact that the technical characteristics of devices are determined by relaxation mechanisms of nonequilibrium processes that occur in the material upon absorption of electromagnetic radiation. In this paper, we focused on the study of the relaxation of nonequilibrium processes in superconducting materials such as highly boron-doped polycrystalline diamond films, highly disordered titanium nitride (TiN) films and ultrathin amorphous tungsten silicide films (WSi). The experimental data allowed us to determine the temperature dependence of the inelastic relaxation time in the studied materials. These results can help us to evaluate the applicability of these materials for the different types of superconducting detectors.

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Zhang, Zhe, Pierre Delplace y Romain Fleury. "Superior robustness of anomalous non-reciprocal topological edge states". Nature 598, n.º 7880 (13 de octubre de 2021): 293–97. http://dx.doi.org/10.1038/s41586-021-03868-7.

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AbstractRobustness against disorder and defects is a pivotal advantage of topological systems1, manifested by the absence of electronic backscattering in the quantum-Hall2 and spin-Hall effects3, and by unidirectional waveguiding in their classical analogues4,5. Two-dimensional (2D) topological insulators4–13, in particular, provide unprecedented opportunities in a variety of fields owing to their compact planar geometries, which are compatible with the fabrication technologies used in modern electronics and photonics. Among all 2D topological phases, Chern insulators14–25 are currently the most reliable designs owing to the genuine backscattering immunity of their non-reciprocal edge modes, brought via time-reversal symmetry breaking. Yet such resistance to fabrication tolerances is limited to fluctuations of the same order of magnitude as their bandgap, limiting their resilience to small perturbations only. Here we investigate the robustness problem in a system where edge transmission can survive disorder levels with strengths arbitrarily larger than the bandgap—an anomalous non-reciprocal topological network. We explore the general conditions needed to obtain such an unusual effect in systems made of unitary three-port non-reciprocal scatterers connected by phase links, and establish the superior robustness of anomalous edge transmission modes over Chern ones to phase-link disorder of arbitrarily large values. We confirm experimentally the exceptional resilience of the anomalous phase, and demonstrate its operation in various arbitrarily shaped disordered multi-port prototypes. Our results pave the way to efficient, arbitrary planar energy transport on 2D substrates for wave devices with full protection against large fabrication flaws or imperfections.

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Du, Mu, Maoquan Huang, Xiyu Yu, Xingjie Ren y Qie Sun. "Structure Design of Polymer-Based Films for Passive Daytime Radiative Cooling". Micromachines 13, n.º 12 (2 de diciembre de 2022): 2137. http://dx.doi.org/10.3390/mi13122137.

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Passive daytime radiative cooling (PDRC), a cooling method that needs no additional energy, has become increasingly popular in recent years. The combination of disordered media and polymeric photonics will hopefully lead to the large-scale fabrication of high-performance PDRC devices. This work aims to study two typical PDRC structures, the randomly distributed silica particle (RDSP) structure and the porous structure, and systematically investigates the effects of structural parameters (diameter D, volume fraction fv, and thickness t) on the radiative properties of the common plastic materials. Through the assistance of the metal-reflective layer, the daytime cooling power Pnet of the RDSP structures is slightly higher than that of the porous structures. Without the metal-reflective layer, the porous PC films can still achieve good PDRC performance with Pnet of 86 W/m2. Furthermore, the effective thermal conductivity of different structures was evaluated. The single-layer porous structure with optimally designed architecture can achieve both good optical and insulating performance, and it is the structure with the most potential in PDRC applications. The results can provide guidelines for designing high-performance radiative cooling films.

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Zhu, Yuntong y Jennifer L. M. Rupp. "Designing High Entropy Amorphous Oxides for Li-Battery Electrolytes". ECS Meeting Abstracts MA2022-02, n.º 4 (9 de octubre de 2022): 472. http://dx.doi.org/10.1149/ma2022-024472mtgabs.

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Amorphous Li-oxides such as LiPON and amorphous Li garnet are considered as promising solid-state electrolytes for use in hybrid or all-solid-state oxide- and sulfide-based batteries as separators or protective layers.1-3 These materials possess several appealing characteristics, such as their intrinsic grain-boundary-free nature and relatively low manufacturing temperature (ranging from room temperature to 600 °C), which facilitates co-synthesis with Co-substituted or even Co-free cathodes that are unstable at standard electrolyte sintering temperatures. Alternatively, they can be applied as protective coatings toward Li anodes and other Li-free anode concepts, bridging the electrochemical stability voltage gap with liquid electrolytes or catholytes and preventing uneven interfacial reactions. The amorphous Li-oxides can be classified based on their structural entropy, i.e., the number and types of local bonding units (LBUs). As of today, ‘low entropy’ amorphous LiPON with only one type of LBU achieves the highest cycle number and battery lifetime.4 ‘High entropy’ amorphous Li-ion conductors, such as Li perovskites or Li garnets, exhibit an unusually high number of LBUs. local ordering and the Li-ion dynamics remain poorly understood, in part owing to the difficulty in characterizing their disordered states. This study employed a novel synthesis protocol to stabilize amorphous Al-doped Li garnets, representing so far the highest number of LBUs (≥ 4) in an amorphous Li-ion conductor.5 We resolved their phase evolution and local structures by a combination of spectroscopy, microscopy, and calorimetry techniques. A much wider (<680 °C) but processing-friendly temperature range was identified to stabilize various amorphous phases with edge- and face-sharing Zr, La, and Li LBUs that do not conform to the formation rules for Zachariasen’s glasses. These amorphous Li-ion conductors reveal an unusual setting in which Li and Zr act as network formers and La acts as a network modifier, with the highest Li-dynamics observed for smaller Li–O and Zr–O coordination among the amorphous phases. Our insight provides fundamental guidelines for the phase, local structure, and Li-transport modulation for amorphous Li garnets and pave the way for their integration in next-generation solid-state or hybrid battery designs with enhanced safety and lifetime. Acknowledgments Y.Z. acknowledges financial support provided by the MIT Energy Initiative fellowship offered by ExxonMobil. This research was supported by Samsung Electronics. This research was performed in part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which was supported by the National Science Foundation under NSF award no. 1541959. CNS is a part of Harvard University. This research used resources of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, and was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357, and the Canadian Light Source and its funding partners. References [1] Zhu, Yuntong, et al. "Lithium-film ceramics for solid-state lithionic devices." Nature Reviews Materials 6.4 (2021): 313-331. [2] Balaish, Moran, et al. "Processing thin but robust electrolytes for solid-state batteries." Nature Energy 6.3 (2021): 227-239. [3] Garbayo, Iñigo, et al. "Glass‐Type Polyamorphism in Li‐Garnet Thin Film Solid State Battery Conductors." Advanced Energy Materials 8.12 (2018): 1702265. [4] Li, Juchuan, et al. "Solid electrolyte: the key for high‐voltage lithium batteries." Advanced Energy Materials 5.4 (2015): 1401408. [5] Zhu, Yuntong, et al., "High entropy amorphous Li-battery electrolytes.", Under Review (2022)

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Cerjan, Alexander, Mohan Wang, Sheng Huang, Kevin P. Chen y Mikael C. Rechtsman. "Thouless pumping in disordered photonic systems". Light: Science & Applications 9, n.º 1 (19 de octubre de 2020). http://dx.doi.org/10.1038/s41377-020-00408-2.

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Abstract Thouless charge pumping protocols provide a route for one-dimensional systems to realize topological transport. Here, using arrays of evanescently coupled optical waveguides, we experimentally demonstrate bulk Thouless pumping in the presence of disorder. The degree of pumping is quite tolerant to significant deviations from adiabaticity as well as the addition of system disorder until the disorder is sufficiently strong to reduce the bulk mobility gap of the system to be on the scale of the modulation frequency of the system. Moreover, we show that this approach realizes near-full-unit-cell transport per pump cycle for a physically relevant class of localized initial system excitations. Thus, temporally pumped systems can potentially be used as a design principle for a new class of modulated slow-light devices that are resistant to system disorder.

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Chen Yang, Zhang Tian-Yang, Guo Guang-Can y Ren Xi-Feng. "Integrated photonic quantum simulation". Acta Physica Sinica, 2022, 0. http://dx.doi.org/10.7498/aps.71.20221938.

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Using a controllable quantum system to study another complicated or hard-to-control quantum system, quantum simulation provides a valuable tool to explore complex unknown quantum systems, which cannot be simulated on classical computers due to the exponential explosion of the Hilbert space. Among different kinds of physical realizations of quantum simulation, integrated optical systems have emerged as appropriate platforms in recent years, due to the advantages of flexible control, weak decoherence and lack of interaction in optical systems. In this review, we attempt to introduce some of the basic models used for quantum simulation in integrated photonic systems. The structure of this review article is shown as follows. Section 2 introduces the commonly used material platforms for integrated quantum simulation, including the silicon-based, lithium niobate-based integrated circuits and the femtosecond laser direct writing optical waveguides. Several integrated optical platforms such as the coupled waveguide arrays, photonic crystals, coupled resonator arrays and multiport interferometers are introduced. In section 3, we focus on the analog quantum simulation in the integrated photonic platform, including Anderson localization of light in disordered systems, various kinds of topological insulators, nonlinear and non-Hermitian systems. More concretely, section 3.1 is devoted to integrated photonic realizations of disordered and quasi-periodic systems. In section 3.2, we review integrated photonic realizations of the topological insulators with and without time-reversal symmetry, including Floquet topological insulators, quantum spin hall system, anomalous quantum hall system, valley hall system, Su-Schrieffer-Heeger (SSH) model and photonic topological Anderson insulators. Besides, topological insulator lasers and topologically protected quantum photon sources are briefly reviewed. The nonlinear and non-Hermitian integrated optical systems are reviewed in section 3.3. In section 4, we introduce integrated digital quantum simulations based on the multiport interferometers, including the discrete-time quantum random walk, boson sampling and molecular simulation. In section 5, we summarize the content of the article and outlook on the future perspectives of the integrated photonic quantum simulation. We believe that integrated photonic platforms will continue to provide an excellent platform for quantum simulation. More practical applications will be found based on this system, combining the fields of topological photonics, laser technologies, quantum information, nonlinear and non-Hermitian physics.

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Jung, Pawel S., Georgios G. Pyrialakos, Fan O. Wu, Midya Parto, Mercedeh Khajavikhan, Wieslaw Krolikowski y Demetrios N. Christodoulides. "Thermal control of the topological edge flow in nonlinear photonic lattices". Nature Communications 13, n.º 1 (29 de julio de 2022). http://dx.doi.org/10.1038/s41467-022-32069-7.

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AbstractThe chaotic evolution resulting from the interplay between topology and nonlinearity in photonic systems generally forbids the sustainability of optical currents. Here, we systematically explore the nonlinear evolution dynamics in topological photonic lattices within the framework of optical thermodynamics. By considering an archetypical two-dimensional Haldane photonic lattice, we discover several prethermal states beyond the topological phase transition point and a stable global equilibrium response, associated with a specific optical temperature and chemical potential. Along these lines, we provide a consistent thermodynamic methodology for both controlling and maximizing the unidirectional power flow in the topological edge states. This can be achieved by either employing cross-phase interactions between two subsystems or by exploiting self-heating effects in disordered or Floquet topological lattices. Our results indicate that photonic topological systems can in fact support robust photon transport processes even under the extreme complexity introduced by nonlinearity, an important feature for contemporary topological applications in photonics.

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29

Klatt, Michael A., Paul J. Steinhardt y Salvatore Torquato. "Wave propagation and band tails of two-dimensional disordered systems in the thermodynamic limit". Proceedings of the National Academy of Sciences 119, n.º 52 (20 de diciembre de 2022). http://dx.doi.org/10.1073/pnas.2213633119.

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Understanding the nature and formation of band gaps associated with the propagation of electromagnetic, electronic, or elastic waves in disordered materials as a function of system size presents fundamental and technological challenges. In particular, a basic question is whether band gaps in disordered systems exist in the thermodynamic limit. To explore this issue, we use a two-stage ensemble approach to study the formation of complete photonic band gaps (PBGs) for a sequence of increasingly large systems spanning a broad range of two-dimensional photonic network solids with varying degrees of local and global order, including hyperuniform and nonhyperuniform types. We discover that the gap in the density of states exhibits exponential tails and the apparent PBGs rapidly close as the system size increases for nearly all disordered networks considered. The only exceptions are sufficiently stealthy hyperuniform cases for which the band gaps remain open and the band tails exhibit a desirable power-law scaling reminiscent of the PBG behavior of photonic crystals in the thermodynamic limit.

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30

Novitsky, Denis V., Dmitry Lyakhov, Dominik Michels, Dmitrii Redka, Alexander A. Pavlov y Alexander S. Shalin. "Controlling wave fronts with tunable disordered non-Hermitian multilayers". Scientific Reports 11, n.º 1 (26 de febrero de 2021). http://dx.doi.org/10.1038/s41598-021-84271-0.

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AbstractUnique and flexible properties of non-Hermitian photonic systems attract ever-increasing attention via delivering a whole bunch of novel optical effects and allowing for efficient tuning light-matter interactions on nano- and microscales. Together with an increasing demand for the fast and spatially compact methods of light governing, this peculiar approach paves a broad avenue to novel optical applications. Here, unifying the approaches of disordered metamaterials and non-Hermitian photonics, we propose a conceptually new and simple architecture driven by disordered loss-gain multilayers and, therefore, providing a powerful tool to control both the passage time and the wave-front shape of incident light with different switching times. For the first time we show the possibility to switch on and off kink formation by changing the level of disorder in the case of adiabatically raising wave fronts. At the same time, we deliver flexible tuning of the output intensity by using the nonlinear effect of loss and gain saturation. Since the disorder strength in our system can be conveniently controlled with the power of the external pump, our approach can be considered as a basis for different active photonic devices.

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31

Steinfurth, Andrea, Ivor Krešić, Sebastian Weidemann, Mark Kremer, Konstantinos G. Makris, Matthias Heinrich, Stefan Rotter y Alexander Szameit. "Observation of photonic constant-intensity waves and induced transparency in tailored non-Hermitian lattices". Science Advances 8, n.º 21 (27 de mayo de 2022). http://dx.doi.org/10.1126/sciadv.abl7412.

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Light propagation is strongly affected by scattering due to imperfections in the complex medium. It has been recently theoretically predicted that a scattering-free transport through an inhomogeneous medium is achievable by non-Hermitian tailoring of the complex refractive index. Here, we implement photonic constant-intensity waves in an inhomogeneous, linear, discrete mesh lattice. By extending the existing theoretical framework, we experimentally show that a driven non-Hermitian tailoring allows us to control the propagation and diffraction of light even in highly disordered systems. In this vein, we demonstrate the transmission of shape-preserving beams and the seemingly undistorted propagation of light excitations across a strongly inhomogeneous non-Hermitian photonic lattice that can be realized by coupled optical fiber loops. Our results lead to a deeper understanding of non-Hermitian wave control and further contribute to the development of non-Hermitian photonics.

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32

Torquato, Salvatore. "Extraordinary disordered hyperuniform multifunctional composites". Journal of Composite Materials, 8 de agosto de 2022, 002199832211164. http://dx.doi.org/10.1177/00219983221116432.

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A variety of performance demands are being placed on material systems, including desirable mechanical, thermal, electrical, optical, acoustic and flow properties. The purpose of the present article is to review the emerging field of disordered hyperuniform composites and their novel multifunctional characteristics. Disordered hyperuniform media are exotic amorphous states of matter that are characterized by an anomalous suppression of large-scale volume-fraction fluctuations compared to those in “garden-variety” disordered materials. Such unusual composites can have advantages over their periodic counterparts, such as unique or nearly optimal, direction-independent physical properties and robustness against defects. It will be shown that disordered hyperuniform composites and porous media can be endowed with a broad spectrum of extraordinary physical properties, including photonic, phononic, transport, chemical and mechanical characteristics that are only beginning to be discovered.

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33

Dikopoltsev, Alex, Sebastian Weidemann, Mark Kremer, Andrea Steinfurth, Hanan Herzig Sheinfux, Alexander Szameit y Mordechai Segev. "Observation of Anderson localization beyond the spectrum of the disorder". Science Advances 8, n.º 21 (27 de mayo de 2022). http://dx.doi.org/10.1126/sciadv.abn7769.

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Anderson localization predicts that transport in one-dimensional uncorrelated disordered systems comes to a complete halt, experiencing no transport whatsoever. However, in reality, a disordered physical system is always correlated because it must have a finite spectrum. Common wisdom in the field states that localization is dominant only for wave packets whose spectral extent resides within the region of the wave number span of the disorder. Here, we show experimentally that Anderson localization can occur and even be dominant for wave packets residing entirely outside the spectral extent of the disorder. We study the evolution of wave packets in synthetic photonic lattices containing bandwidth-limited (correlated) disorder and observe strong localization for wave packets centered at twice the mean wave number of the disorder spectral extent and at low wave numbers, both far beyond the spectrum of the disorder. Our results shed light on fundamental aspects of disordered systems and offer avenues for using spectrally shaped disorder for controlling transport.

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34

Chen, Jianfeng y Zhi-Yuan Li. "Topological photonic states in gyromagnetic photonic crystals: physics, properties and applications". Chinese Physics B, 19 de septiembre de 2022. http://dx.doi.org/10.1088/1674-1056/ac92d7.

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Abstract Topological photonic states (TPSs) as a new type of waveguide state with one-way transport property can resist backscattering and are impervious to defects, disorders and metallic obstacles. Gyromagnetic photonic crystal (GPC) is the first artificial microstructure to implement TPSs, and it is also one of the most important platforms for generating truly one-way TPSs and exploring their novel physical properties, transport phenomena and advanced applications. Herein, we present a brief review of the fundamental physics, novel properties and practical applications of TPSs based on GPCs. We first examine chiral one-way edge states existing in uniformly magnetized GPCs of ordered and disordered lattices, antichiral one-way edge states in cross magnetized GPCs, and robust one-way bulk states in heterogeneously magnetized GPCs. Then, we discuss the strongly coupling effect between two co-propagating (or counter-propagating) TPSs and the resulting physical phenomena and device applications. Finally, we analyze the key issues and prospect the future development trends for TPSs in GPCs. The purpose of this brief review is to provide an overview of the main features of TPSs in GPC systems and offer a useful guidance and motivation for interested scientists and engineers working in related scientific and technological areas.

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35

Vicentini, Filippo, Fabrizio Minganti, Alberto Biella, Giuliano Orso y Cristiano Ciuti. "Optimal stochastic unraveling of disordered open quantum systems: Application to driven-dissipative photonic lattices". Physical Review A 99, n.º 3 (14 de marzo de 2019). http://dx.doi.org/10.1103/physreva.99.032115.

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36

Herzig Sheinfux, Hanan, Ido Kaminer, Azriel Z. Genack y Mordechai Segev. "Interplay between evanescence and disorder in deep subwavelength photonic structures". Nature Communications 7, n.º 1 (6 de octubre de 2016). http://dx.doi.org/10.1038/ncomms12927.

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AbstractDeep subwavelength features are expected to have minimal impact on wave transport. Here we show that in contrast to this common understanding, disorder can have a dramatic effect in a one-dimensional disordered optical system with spatial features a thousand times smaller than the wavelength. We examine a unique regime of Anderson localization where the localization length is shown to scale linearly with the wavelength instead of diverging, because of the role of evanescent waves. In addition, we demonstrate an unusual order of magnitude enhancement of transmission induced due to localization. These results are described for electromagnetic waves, but are directly relevant to other wave systems such as electrons in multi-quantum-well structures.

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37

Ragavendran, Lakshmi Thara, Aruna Priya P y Chittaranjan Nayak. "Numerical study of temperature and pressure effect on one dimensional random photonic crystal used as biosensors in the detection of breast cancer cells". Physica Scripta, 20 de diciembre de 2022. http://dx.doi.org/10.1088/1402-4896/acad43.

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Abstract For the past few decades, investigations of cancer cells were made using periodic/defective-periodic photonic structures. Utilizing the unique properties of a disordered photonic crystal for detecting the bio-analytes is still missing. This work incorporates the opto-biological properties of one-dimensional random photonic systems to design the two differently randomized biosensors for sensing breast cancer cells. These random sensors are differentiated from one another based on their random arrangements and random thicknesses. To obtain efficient outcomes, the thickness of the dielectric layers and sensing layer is optimized. Through the transfer matrix method, the sensing characteristics of the biosensors are investigated for different pressures (0-6 GPa) and temperatures (-125°C to 25°C). At the optimal range, the proposed Biosensors I and II, show a high sensitivity of 1372.549 nm/RIU. Among both sensors, Random Biosensor I exhibits a high-quality factor of 12925, a maximum FOM of 4575.163 RIU-1, and a very low detection limit in the order of 5.82857E-06 RIU. The designed sensor is capable of sensing very minuscule changes in the bio-analytes effectually. The proposed biosensor shows high sensitivity than the previous literature even in the normal incident of light.

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38

Lin, Ho-Chun, Zeyu Wang y Chia Wei Hsu. "Fast multi-source nanophotonic simulations using augmented partial factorization". Nature Computational Science, 15 de diciembre de 2022. http://dx.doi.org/10.1038/s43588-022-00370-6.

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AbstractNumerical solutions of Maxwell’s equations are indispensable for nanophotonics and electromagnetics but are constrained when it comes to large systems, especially multi-channel ones such as disordered media, aperiodic metasurfaces and densely packed photonic circuits where the many inputs require many large-scale simulations. Conventionally, before extracting the quantities of interest, Maxwell’s equations are first solved on every element of a discretization basis set that contains much more information than is typically needed. Furthermore, such simulations are often performed one input at a time, which can be slow and repetitive. Here we propose to bypass the full-basis solutions and directly compute the quantities of interest while also eliminating the repetition over inputs. We do so by augmenting the Maxwell operator with all the input source profiles and all the output projection profiles, followed by a single partial factorization that yields the entire generalized scattering matrix via the Schur complement, with no approximation beyond discretization. This method applies to any linear partial differential equation. Benchmarks show that this approach is 1,000–30,000,000 times faster than existing methods for two-dimensional systems with about 10,000,000 variables. As examples, we demonstrate simulations of entangled photon backscattering from disorder and high-numerical-aperture metalenses that are thousands of wavelengths wide.

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39

Lin, Quan, Tianyu Li, Lei Xiao, Kunkun Wang, Wei Yi y Peng Xue. "Observation of non-Hermitian topological Anderson insulator in quantum dynamics". Nature Communications 13, n.º 1 (9 de junio de 2022). http://dx.doi.org/10.1038/s41467-022-30938-9.

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AbstractDisorder and non-Hermiticity dramatically impact the topological and localization properties of a quantum system, giving rise to intriguing quantum states of matter. The rich interplay of disorder, non-Hermiticity, and topology is epitomized by the recently proposed non-Hermitian topological Anderson insulator that hosts a plethora of exotic phenomena. Here we experimentally simulate the non-Hermitian topological Anderson insulator using disordered photonic quantum walks, and characterize its localization and topological properties. In particular, we focus on the competition between Anderson localization induced by random disorder, and the non-Hermitian skin effect under which all eigenstates are squeezed toward the boundary. The two distinct localization mechanisms prompt a non-monotonous change in profile of the Lyapunov exponent, which we experimentally reveal through dynamic observables. We then probe the disorder-induced topological phase transitions, and demonstrate their biorthogonal criticality. Our experiment further advances the frontier of synthetic topology in open systems.

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40

Zhou, Qingjia, Yangyang Fu, Lujun Huang, Qiannan Wu, Andrey Miroshnichenko, Lei Gao y Yadong Xu. "Geometry symmetry-free and higher-order optical bound states in the continuum". Nature Communications 12, n.º 1 (19 de julio de 2021). http://dx.doi.org/10.1038/s41467-021-24686-5.

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AbstractGeometrical symmetry plays a significant role in implementing robust, symmetry-protected, bound states in the continuum (BICs). However, this benefit is only theoretical in many cases since fabricated samples’ unavoidable imperfections may easily break the stringent geometrical requirements. Here we propose an approach by introducing the concept of geometrical-symmetry-free but symmetry-protected BICs, realized using the static-like environment induced by a zero-index metamaterial (ZIM). We find that robust BICs exist and are protected from the disordered distribution of multiple objects inside the ZIM host by its physical symmetries rather than geometrical ones. The geometric-symmetry-free BICs are robust, regardless of the objects’ external shapes and material parameters in the ZIM host. We further show theoretically and numerically that the existence of those higher-order BICs depends only on the number of objects. By practically designing a structural ZIM waveguide, the existence of BICs is numerically confirmed, as well as their independence on the presence of geometrical symmetry. Our findings provide a way of realizing higher-order BICs and link their properties to the disorder of photonic systems.

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41

Rizzo, Giorgio, Marco Lo Presti, Cinzia Giannini, Teresa Sibillano, Antonella Milella, Giulia Guidetti, Roberta Musio, Fiorenzo G. Omenetto y Gianluca M. Farinola. "Bombyx mori Silk Fibroin Regeneration in Solution of Lanthanide Ions: A Systematic Investigation". Frontiers in Bioengineering and Biotechnology 9 (10 de junio de 2021). http://dx.doi.org/10.3389/fbioe.2021.653033.

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Silk Fibroin (SF) obtained from Bombyx mori is a very attractive biopolymer that can be useful for many technological applications, from optoelectronics and photonics to biomedicine. It can be processed from aqueous solutions to obtain many scaffolds. SF dissolution is possible only with the mediation of chaotropic salts that disrupt the secondary structure of the protein. As a consequence, recovered materials have disordered structures. In a previous paper, it was shown that, by modifying the standard Ajisawa’s method by using a lanthanide salt, CeCl3, as the chaotropic agent, it is possible to regenerate SF as a fibrous material with a very ordered structure, similar to that of the pristine fiber, and doped with Ce+3 ions. Since SF exhibits a moderate fluorescence which can be enhanced by the incorporation of organic molecules, ions and nanoparticles, the possibility of doping it with lanthanide ions could be an appealing approach for the development of new photonic systems. Here, a systematic investigation of the behavior of degummed SF in the presence of all lanthanide ions, Ln+3, is reported. It has been found that all lanthanide chlorides are chaotropic salts for solubilizing SF. Ln+3 ions at the beginning and the end of the series (La+3, Pr+3, Er+3, Tm+3, Yb+3, Lu+3) favor the reprecipitation of fibrous SF as already found for Ce+3. In most cases, the obtained fiber preserves the morphological and structural features of the pristine SF. With the exception of SF treated with La+3, Tm+3, and Lu+3, for all the fibers re-precipitated a concentration of Ln+3 between 0.2 and 0.4% at was measured, comparable to that measured for Ce+3-doped SF.

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42

Jupri, Siti Aishah, Sib Krishna Ghoshal, Muhammad Firdaus Omar y Sunita Sharma. "Improved absorbance of holmium activated magnesium-zinc-sulfophosphate glass". Malaysian Journal of Fundamental and Applied Sciences 13, n.º 3 (28 de septiembre de 2017). http://dx.doi.org/10.11113/mjfas.v13n3.559.

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Constant efforts are dedicated to overcome the limitations of phosphate based glass system, where sulfophosphate glasses (SPGs) played a key role. Rare earth ions (REIs) doped magnesium zinc SPG (MZSPG) systems are technologically prospective due to their several unique attributes. Construction of integrated light ampliﬁer and solid state laser needs the maximum gain within small component dimensions. Thus, Ho3+ ions doped SPGs are believed to meet this demand. Ho3+ ions having sharp optical absorption peaks in the spectral range of 200–900 nm is useful for diversified applications. Conversely, SPGs comprising of oxides of sulphur, phosphorous and at least one other component with SO42- ions contents lower than PO43- with low melting temperature makes them a distinctive class of technologically potential disordered system. In this view, modification of Ho3+ ions absorbance inside SPGs network is challenging. To achieve this goal, following melt-quenching route we prepared a series of Ho3+-doped MZSPG system of composition (60-x)P2O5-(20)ZnSO4-(20)MgO–(x)Ho2O3, where x = 0.0, 0.5, 1.0, 1.5 2.0, and 2.5 mol%. The influence of Ho2O3 concentration on the density, refractive index, and optical absorption properties of the synthesized glass system is examined. The density and refractive index is found to increase with increasing Ho2O3 concentration. The absorption spectra revealed nine prominent peaks centered at 387, 418, 450, 484, 538, 642, 1148 and 1945 nm. The glass absorbance is enhanced with increasing Ho3+ contents. Optical band gap energy is found to range from 3.847 to 3.901 eV. The reduction of Urbach energy from 0.257 to 0.191 eV with increasing Ho3+ contents verified the shrinkage of glass network structure and lowering of defect mediated disorder. In-depth investigations on the structural and optical properties of MZSPG system are underway to achieve the milestones set for photonic devices.

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43

Tsabedze, Sebenzile, Nkosikhona Dlamini y Simiso K. Khumbulani Mkhonta. "Regularity and resilience of short-range order in uniformly randomized lattices". Journal of Physics Communications, 11 de octubre de 2022. http://dx.doi.org/10.1088/2399-6528/ac9954.

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Abstract Randomly perturbed lattice models play a vital role in the exploration of novel quasi-disordered structures such as disordered photonic crystals that combine the coherent optical effects of crystals and the broadband, isotropic power spectra of disordered media. Recent studies have shown that the Bragg scattering peaks of uniformly randomized lattices can be switch-on and -off by increasing the perturbation strength while preserving the long-range order of the underlying lattice. In this work, we investigate the pair correlation statistics of uniformly randomized lattices focusing on the impact of the perturbations on the system's short-range order. We find that locally isotropic perturbations generate disordered structures with resilient hyperuniformity and short-range order. The interplay of these two properties has been discovered to be critical in the design of disordered materials with enhanced photonic band gaps and light absorption. The present study provides an alternative approach for designing partially disordered hyperuniform structures.

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44

Tomarchio, Luca, Salvatore Macis, Annalisa D’Arco, Sen Mou, Antonio Grilli, Martina Romani, Mariangela Cestelli Guidi et al. "Disordered photonics behavior from terahertz to ultraviolet of a three-dimensional graphene network". NPG Asia Materials 13, n.º 1 (19 de noviembre de 2021). http://dx.doi.org/10.1038/s41427-021-00341-9.

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AbstractThe diffusion of light by random materials is a general phenomenon that appears in many different systems, spanning from colloidal suspension in liquid crystals to disordered metal sponges and paper composed of random fibers. Random scattering is also a key element behind mimicry of several animals, such as white beetles and chameleons. Here, random scattering is related to micro and nanosized spatial structures affecting a broad electromagnetic region. In this work, we have investigated how random scattering modulates the optical properties, from terahertz to ultraviolet light, of a novel functional material, i.e., a three-dimensional graphene (3D Graphene) network based on interconnected high-quality two-dimensional graphene layers. Here, random scattering generates a high-frequency pass-filter behavior. The optical properties of these graphene structures bridge the nanoworld into the macroscopic world, paving the way for their use in novel optoelectronic devices.

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45

Kaiser, Christina, Oskar J. Sandberg, Nasim Zarrabi, Wei Li, Paul Meredith y Ardalan Armin. "A universal Urbach rule for disordered organic semiconductors". Nature Communications 12, n.º 1 (28 de junio de 2021). http://dx.doi.org/10.1038/s41467-021-24202-9.

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AbstractIn crystalline semiconductors, absorption onset sharpness is characterized by temperature-dependent Urbach energies. These energies quantify the static, structural disorder causing localized exponential-tail states, and dynamic disorder from electron-phonon scattering. Applicability of this exponential-tail model to disordered solids has been long debated. Nonetheless, exponential fittings are routinely applied to sub-gap absorption analysis of organic semiconductors. Herein, we elucidate the sub-gap spectral line-shapes of organic semiconductors and their blends by temperature-dependent quantum efficiency measurements. We find that sub-gap absorption due to singlet excitons is universally dominated by thermal broadening at low photon energies and the associated Urbach energy equals the thermal energy, regardless of static disorder. This is consistent with absorptions obtained from a convolution of Gaussian density of excitonic states weighted by Boltzmann-like thermally activated optical transitions. A simple model is presented that explains absorption line-shapes of disordered systems, and we also provide a strategy to determine the excitonic disorder energy. Our findings elaborate the meaning of the Urbach energy in molecular solids and relate the photo-physics to static disorder, crucial for optimizing organic solar cells for which we present a revisited radiative open-circuit voltage limit.

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46

Matityahu, Shlomi, Hartmut Schmidt, Alexander Bilmes, Alexander Shnirman, Georg Weiss, Alexey V. Ustinov, Moshe Schechter y Jürgen Lisenfeld. "Dynamical decoupling of quantum two-level systems by coherent multiple Landau–Zener transitions". npj Quantum Information 5, n.º 1 (diciembre de 2019). http://dx.doi.org/10.1038/s41534-019-0228-x.

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AbstractIncreasing and stabilizing the coherence of superconducting quantum circuits and resonators is of utmost importance for various technologies, ranging from quantum information processors to highly sensitive detectors of low-temperature radiation in astrophysics. A major source of noise in such devices is a bath of quantum two-level systems (TLSs) with broad distribution of energies, existing in disordered dielectrics and on surfaces. Here we study the dielectric loss of superconducting resonators in the presence of a periodic electric bias field, which sweeps near-resonant TLSs in and out of resonance with the resonator, resulting in a periodic pattern of Landau–Zener transitions. We show that at high sweep rates compared to the TLS relaxation rate, the coherent evolution of the TLS over multiple transitions yields a significant reduction in the dielectric loss relative to the intrinsic value. This behavior is observed both in the classical high-power regime and in the quantum single-photon regime, possibly suggesting a viable technique to dynamically decouple TLSs from a qubit.

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47

Giordani, Taira, Walter Schirmacher, Giancarlo Ruocco y Marco Leonetti. "Transverse and Quantum Localization of Light: A Review on Theory and Experiments". Frontiers in Physics 9 (25 de agosto de 2021). http://dx.doi.org/10.3389/fphy.2021.715663.

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Anderson localization is an interference effect yielding a drastic reduction of diffusion—including complete hindrance—of wave packets such as sound, electromagnetic waves, and particle wave functions in the presence of strong disorder. In optics, this effect has been observed and demonstrated unquestionably only in dimensionally reduced systems. In particular, transverse localization (TL) occurs in optical fibers, which are disordered orthogonal to and translationally invariant along the propagation direction. The resonant and tube-shaped localized states act as micro-fiber-like single-mode transmission channels. Since the proposal of the first TL models in the early eighties, the fabrication technology and experimental probing techniques took giant steps forwards: TL has been observed in photo-refractive crystals, in plastic optical fibers, and also in glassy platforms, while employing direct laser writing is now possible to tailor and “design” disorder. This review covers all these aspects that are today making TL closer to applications such as quantum communication or image transport. We first discuss nonlinear optical phenomena in the TL regime, enabling steering of optical communication channels. We further report on an experiment testing the traditional, approximate way of introducing disorder into Maxwell’s equations for the description of TL. We find that it does not agree with our findings for the average localization length. We present a new theory, which does not involve an approximation and which agrees with our findings. Finally, we report on some quantum aspects, showing how a single-photon state can be localized in some of its inner degrees of freedom and how quantum phenomena can be employed to secure a quantum communication channel.

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