1
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Plouraboué F. Quantum graph wave external triggering: Energy transfer and damping. Phys Rev E 2024; 109:054310. [PMID: 38907393 DOI: 10.1103/physreve.109.054310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Accepted: 02/19/2024] [Indexed: 06/24/2024]
Abstract
The propagation of wave trains resulting from a local external trigger inside a network described by a metric graph is analyzed using quantum graph theory. The external trigger is a finite-time perturbation imposed at one vertex of the graph, leading to a consecutive wave train into the network, supposedly at rest before the applied external perturbation. A complete analytical solution for the induced wave train is found having a specific spectrum as well as mode's amplitudes. Furthermore the precise condition by which the external trigger can transfer a maximal energy to any specific natural mode of the quantum graph is derived. Finally, the wave damping associated with boundary-layer dissipation is computed within a multiple time-scale asymptotic analysis. Exponential damping rates are explicitly found related to their corresponding mode's eigenvalue. Each mode energy is then obtained, as well as their exponential damping rate. The relevance of these results to the physics of waves within networks are discussed.
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2
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Kumar B, Schulz SA, Sebbah P. Temperature-controlled spectral tuning of a single wavelength polymer-based solid-state random laser. OPTICS EXPRESS 2024; 32:4317-4326. [PMID: 38297635 DOI: 10.1364/oe.505162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 11/23/2023] [Indexed: 02/02/2024]
Abstract
We demonstrate temperature-controlled spectral tunability of a partially-pumped single-wavelength random laser in a solid-state random laser based on DCM [4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran] doped PMMA (polymethyl methacrylate) dye. By carefully shaping the spatial profile of the pump, we first achieve a low-threshold, single-mode random lasing with an excellent side lobe rejection. Notably, we show how temperature-induced changes in the refractive index of the PMMA-DCM layer result in a blue shift of this single lasing mode. We demonstrate spectral tunability over an 8nm-wide bandwidth.
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3
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Sol J, Röntgen M, Del Hougne P. Covert Scattering Control in Metamaterials with Non-Locally Encoded Hidden Symmetry. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2303891. [PMID: 37726008 DOI: 10.1002/adma.202303891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 09/04/2023] [Indexed: 09/21/2023]
Abstract
Symmetries and tunability are of fundamental importance in wave scattering control, but symmetries are often obvious upon visual inspection, which constitutes a significant vulnerability of metamaterial wave devices to reverse-engineering risks. Here, it is theoretically and experimentally shown that a symmetry in the reduced basis of the "primary meta-atoms" that are directly connected to the outside world is sufficient; meanwhile, a suitable topology of non-local interactions between them, mediated by the internal "secondary" meta-atoms, can hide the symmetry from sight in the canonical basis. Covert symmetry-based scattering control in a cable-network metamaterial featuring a hidden parity ( P $\mathcal {P}$ ) symmetry in combination with hidden- P $\mathcal {P}$ -symmetry-preserving and hidden- P $\mathcal {P}$ -symmetry-breaking tuning mechanisms is experimentally demonstrated. Physical-layer security in wired communications is achieved using the domain-wise hidden P $\mathcal {P}$ -symmetry as a shared secret between the sender and the legitimate receiver. Within the approximation of negligible absorption, the first tuning of a complex scattering metamaterial without mirror symmetry to feature exceptional points (EPs) of PT $\mathcal {PT}$ -symmetric reflectionless states, as well as quasi-bound states in the continuum, is reported. These results are reproduced in metamaterials involving non-reciprocal interactions between meta-atoms, including the first observation of reflectionless EPs in a non-reciprocal system.
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Affiliation(s)
- Jérôme Sol
- INSA Rennes, CNRS, IETR-UMR 6164, F-35000, Rennes, France
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4
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Anwar A, Mur M, Humar M. Microcavity- and Microlaser-Based Optical Barcoding: A Review of Encoding Techniques and Applications. ACS PHOTONICS 2023; 10:1202-1224. [PMID: 37215324 PMCID: PMC10197175 DOI: 10.1021/acsphotonics.2c01611] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Indexed: 05/24/2023]
Abstract
Optical microbarcodes have recently received a great deal of interest because of their suitability for a wide range of applications, such as multiplexed assays, cell tagging and tracking, anticounterfeiting, and product labeling. Spectral barcodes are especially promising because they are robust and have a simple readout. In addition, microcavity- and microlaser-based barcodes have very narrow spectra and therefore have the potential to generate millions of unique barcodes. This review begins with a discussion of the different types of barcodes and then focuses specifically on microcavity-based barcodes. While almost any kind of optical microcavity can be used for barcoding, currently whispering-gallery microcavities (in the form of spheres and disks), nanowire lasers, Fabry-Pérot lasers, random lasers, and distributed feedback lasers are the most frequently employed for this purpose. In microcavity-based barcodes, the information is encoded in various ways in the properties of the emitted light, most frequently in the spectrum. The barcode is dependent on the properties of the microcavity, such as the size, shape, and the gain materials. Various applications of these barcodes, including cell tracking, anticounterfeiting, and product labeling are described. Finally, the future prospects for microcavity- and microlaser-based barcodes are discussed.
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Affiliation(s)
- Abdur
Rehman Anwar
- Department
of Condensed Matter Physics, J. Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Maruša Mur
- Department
of Condensed Matter Physics, J. Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Matjaž Humar
- Department
of Condensed Matter Physics, J. Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
- CENN
Nanocenter, Jamova 39, SI-1000 Ljubljana, Slovenia
- Faculty
of Mathematics and Physics, University of
Ljubljana, Jadranska
19, SI-1000 Ljubljana, Slovenia
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5
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Yu S. Evolving scattering networks for engineering disorder. NATURE COMPUTATIONAL SCIENCE 2023; 3:128-138. [PMID: 38177628 PMCID: PMC10766560 DOI: 10.1038/s43588-022-00395-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/22/2022] [Indexed: 01/06/2024]
Abstract
Network science provides a powerful tool for unraveling the complexities of social, technological and biological systems. Constructing networks using wave phenomena is also of great interest in devising advanced hardware for machine learning, as shown in optical neural networks. Although most wave-based networks have employed static network models, the impact of evolving models in network science provides strong motivation to apply dynamical network modeling to wave physics. Here the concept of evolving scattering networks for scattering phenomena is developed. The network is defined by links, node degrees and their evolution processes modeling multi-particle interferences, which directly determine scattering from disordered materials. I demonstrate the concept by examining network-based material classification, microstructure screening and preferential attachment in evolutions, which are applied to stealthy hyperuniformity. The results enable independent control of scattering from different length scales, revealing superdense material phases in short-range order. The proposed concept provides a bridge between wave physics and network science to resolve multiscale material complexities and open-system material design.
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Affiliation(s)
- Sunkyu Yu
- Intelligent Wave Systems Laboratory, Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea.
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6
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Saxena D, Arnaudon A, Cipolato O, Gaio M, Quentel A, Yaliraki S, Pisignano D, Camposeo A, Barahona M, Sapienza R. Sensitivity and spectral control of network lasers. Nat Commun 2022; 13:6493. [PMID: 36310173 PMCID: PMC9618558 DOI: 10.1038/s41467-022-34073-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 10/13/2022] [Indexed: 11/14/2022] Open
Abstract
Recently, random lasing in complex networks has shown efficient lasing over more than 50 localised modes, promoted by multiple scattering over the underlying graph. If controlled, these network lasers can lead to fast-switching multifunctional light sources with synthesised spectrum. Here, we observe both in experiment and theory high sensitivity of the network laser spectrum to the spatial shape of the pump profile, with some modes for example increasing in intensity by 280% when switching off 7% of the pump beam. We solve the nonlinear equations within the steady state ab-initio laser theory (SALT) approximation over a graph and we show selective lasing of around 90% of the strongest intensity modes, effectively programming the spectrum of the lasing networks. In our experiments with polymer networks, this high sensitivity enables control of the lasing spectrum through non-uniform pump patterns. We propose the underlying complexity of the network modes as the key element behind efficient spectral control opening the way for the development of optical devices with wide impact for on-chip photonics for communication, sensing, and computation.
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Affiliation(s)
- Dhruv Saxena
- The Blackett Laboratory, Department of Physics, Imperial College London, London, UK
| | - Alexis Arnaudon
- Department of Mathematics, Imperial College London, London, UK
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Campus Biotech, Geneva, Switzerland
| | - Oscar Cipolato
- The Blackett Laboratory, Department of Physics, Imperial College London, London, UK
| | - Michele Gaio
- The Blackett Laboratory, Department of Physics, Imperial College London, London, UK
| | - Alain Quentel
- The Blackett Laboratory, Department of Physics, Imperial College London, London, UK
| | - Sophia Yaliraki
- Department of Chemistry, Imperial College London, London, UK
| | - Dario Pisignano
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
- Dipartimento di Fisica, Università di Pisa, Pisa, Italy
| | - Andrea Camposeo
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy.
| | | | - Riccardo Sapienza
- The Blackett Laboratory, Department of Physics, Imperial College London, London, UK.
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7
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Inverse Design of Distributed Bragg Reflectors Using Deep Learning. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12104877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Distributed Bragg Reflectors are optical structures capable of manipulating light behaviour, which are formed by stacking layers of thin-film materials. The inverse design of such structures is desirable, but not straightforward using conventional numerical methods. This study explores the application of Deep Learning to the design of a six-layer system, through the implementation of a Tandem Neural Network. The challenge is split into three sections: the generation of training data using the Transfer Matrix method, the design of a Simulation Neural Network (SNN) which maps structural geometry to spectral output, and finally an Inverse Design Neural Network (IDNN) which predicts the geometry required to produce target spectra. The latter enables the designer to develop custom multilayer systems with desired reflection properties. The SNN achieved an average accuracy of 97% across the dataset, with the IDNN achieving 94%. By using this inverse design method, custom-made reflectors can be manufactured in milliseconds, significantly reducing the cost of generating photonic devices and thin-film optics.
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8
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Greenfeld I, Camposeo A, Portone A, Romano L, Allegrini M, Fuso F, Pisignano D, Wagner HD. WO 3 Nanowires Enhance Molecular Alignment and Optical Anisotropy in Electrospun Nanocomposite Fibers: Implications for Hybrid Light-Emitting Systems. ACS APPLIED NANO MATERIALS 2022; 5:3654-3666. [PMID: 35372796 PMCID: PMC8961744 DOI: 10.1021/acsanm.1c04110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/25/2022] [Indexed: 05/31/2023]
Abstract
The molecular orientation in polymer fibers is investigated for the purpose of enhancing their optical properties through nanoscale control by nanowires mixed in electrospun solutions. A prototypical system, consisting of a conjugated polymer blended with polyvinylpyrrolidone, mixed with WO3 nanowires, is analyzed. A critical strain rate of the electrospinning jet is determined by theoretical modeling at which point the polymer network undergoes a stretch transition in the fiber direction, resulting in a high molecular orientation that is partially retained after solidification. Nearing a nanowire boundary, local adsorption of the polymer and hydrodynamic drag further enhance the molecular orientation. These theoretical predictions are supported by polarized scanning near-field optical microscopy experiments, where the dichroic ratio of the light transmitted by the fiber provides evidence of increased orientation nearby nanowires. The addition of nanowires to enhance molecular alignment in polymer fibers might consequently enhance properties such as photoluminescence quantum yield, polarized emission, and tailored energy migration, exploitable in light-emitting photonic and optoelectronic devices and for sensing applications.
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Affiliation(s)
- Israel Greenfeld
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Andrea Camposeo
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa I-56127, Italy
| | - Alberto Portone
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa I-56127, Italy
| | - Luigi Romano
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa I-56127, Italy
| | - Maria Allegrini
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa I-56127, Italy
- Dipartimento
di Fisica, Università di Pisa, Largo B. Pontecorvo 3, Pisa I-56127, Italy
| | - Francesco Fuso
- Dipartimento
di Fisica, Università di Pisa, Largo B. Pontecorvo 3, Pisa I-56127, Italy
| | - Dario Pisignano
- NEST,
Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa I-56127, Italy
- Dipartimento
di Fisica, Università di Pisa, Largo B. Pontecorvo 3, Pisa I-56127, Italy
| | - H. Daniel Wagner
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
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9
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Gong C, Qiao Z, Zhu S, Wang W, Chen YC. Self-Assembled Biophotonic Lasing Network Driven by Amyloid Fibrils in Microcavities. ACS NANO 2021; 15:15007-15016. [PMID: 34533023 DOI: 10.1021/acsnano.1c05266] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Self-assembled biological structures have played a significant role in many living systems for its functionality and distinctiveness. Here, we experimentally demonstrate that the random dynamic behavior of strong light-matter interactions in complex biological structures can provide hidden information on optical coupling in a network. The concept of biophotonic lasing network is therefore introduced, where a self-assembled human amyloid fibril network was confined in a Fabry-Perot optical cavity. Distinctive lasing patterns were discovered from self-assembled amyloids with different structural dimensions (0D, 1D, 2D, and 3D) confined in a microcavity. Network laser emission exhibiting evidence of light coupling at different wavelengths and locations was spectrally resolved. Dynamic changes of lasing patterns can therefore be interpreted into a graph to reveal the optical correlation in biophotonic networks. Our findings indicate that each graph represents the highly unclonable features of a self-assembled network which can sensitively respond to environmental stimulus. This study offers the potential for studying dynamic biological networks through amplified interactions, shedding light on the development of biologically controlled photonic devices, biosensing, and information encryption.
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Affiliation(s)
- Chaoyang Gong
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Zhen Qiao
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Song Zhu
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Wenjie Wang
- Key Lab of Advanced Transducers and Intelligent Control System of Ministry of Education, Taiyuan University of Technology, 79 Yingze Street, Taiyuan 030024, PR China
| | - Yu-Cheng Chen
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459, Singapore
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10
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Yang X, Wen L, Yan J, Bao Y, Chen Q, Camposeo A, Pisignano D, Li B. Energy Dissipation and Asymmetric Excitation in Hybrid Waveguides for Routing and Coloring. J Phys Chem Lett 2021; 12:7034-7040. [PMID: 34286984 DOI: 10.1021/acs.jpclett.1c01690] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The delivery of optical signals from an external light source to a nanoscale waveguide is highly important for the development of nanophotonic circuits. However, the efficient coupling of external light energy into nanophotonic components is difficult and still remains a challenge. Herein, we use an external silica nanofiber to light up an organic-inorganic hybrid nanowaveguide, namely, a system composed of a polymer filament doped with MoS2 quantum dots. Nanofiber-excited nanowaveguides in a crossed geometry are found to asymmetrically couple excitation signals along two opposite directions, with different energy dissipation resulting in different colors of the light emitted by MoS2 quantum dots and collected from the waveguide terminals. Interestingly, rainbow-like light in the hybrid waveguide is achieved by three-in-one mixing of red, green, and blue components. This heterodimensional system of dots in waveguide represents a significant advance toward all-optical routing and full-color display in integrated nanophotonic devices.
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Affiliation(s)
- Xianguang Yang
- Institute of Nanophotonics, Jinan University, Guangzhou 511443, China
| | - Long Wen
- Institute of Nanophotonics, Jinan University, Guangzhou 511443, China
| | - Jiahao Yan
- Institute of Nanophotonics, Jinan University, Guangzhou 511443, China
| | - Yanjun Bao
- Institute of Nanophotonics, Jinan University, Guangzhou 511443, China
| | - Qin Chen
- Institute of Nanophotonics, Jinan University, Guangzhou 511443, China
| | - Andrea Camposeo
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
| | - Dario Pisignano
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
- Dipartimento di Fisica, Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa, Italy
| | - Baojun Li
- Institute of Nanophotonics, Jinan University, Guangzhou 511443, China
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11
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Mao P, Liu C, Niu Y, Qin Y, Song F, Han M, Palmer RE, Maier SA, Zhang S. Disorder-Induced Material-Insensitive Optical Response in Plasmonic Nanostructures: Vibrant Structural Colors from Noble Metals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2007623. [PMID: 33929067 DOI: 10.1002/adma.202007623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/15/2021] [Indexed: 06/12/2023]
Abstract
Materials show various responses to incident light, owing to their unique dielectric functions. A well-known example is the distinct colors displayed by metals, providing probably the simplest method to identify gold, silver, and bronze since ancient times. With the advancement of nanotechnology, optical structures with feature sizes smaller than the optical wavelength have been routinely achieved. In this regime, the optical response is also determined by the geometry of the nanostructures, inspiring flourishing progress in plasmonics, photonic crystals, and metamaterials. Nevertheless, the nature of the materials still plays a decisive role in light-matter interactions, and this material-dependent optical response is widely accepted as a norm in nanophotonics. Here, a counterintuitive system-plasmonic nanostructures composed of different materials but exhibiting almost identical reflection-is proposed and realized. The geometric disorder embedded in the system overwhelms the contribution of the material properties to the electrodynamics. Both numerical simulations and experimental results provide concrete evidence of the insensitivity of the optical response to different plasmonic materials. The same optical response is preserved with various materials, providing great flexibility of freedom in material selection. As a result, the proposed configuration may shed light on novel applications ranging from Raman spectroscopy, photocatalysis, to nonlinear optics.
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Affiliation(s)
- Peng Mao
- School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK
| | - Changxu Liu
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig Maximilians University of Munich, 80539, Munich, Germany
| | - Yubiao Niu
- College of Engineering, Bay Campus, Swansea University, Swansea, SA1 8EN, UK
| | - Yuyuan Qin
- National Laboratory of Solid-State Microstructures, Collaborative Innovation Center of Advanced Microstructures and College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, China
| | - Fengqi Song
- National Laboratory of Solid-State Microstructures, Collaborative Innovation Center of Advanced Microstructures and College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, China
| | - Min Han
- National Laboratory of Solid-State Microstructures, Collaborative Innovation Center of Advanced Microstructures and College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, China
| | - Richard E Palmer
- College of Engineering, Bay Campus, Swansea University, Swansea, SA1 8EN, UK
| | - Stefan A Maier
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig Maximilians University of Munich, 80539, Munich, Germany
- Department of Physics, Imperial College London, London, SW7 2AZ, UK
| | - Shuang Zhang
- School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK
- Department of Physics, University of Hong Kong, Hong Kong, China
- Department of Electrical & Electronic Engineering, University of Hong Kong, Hong Kong, China
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12
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Staudinger P, Mauthe S, Triviño NV, Reidt S, Moselund KE, Schmid H. Wurtzite InP microdisks: from epitaxy to room-temperature lasing. NANOTECHNOLOGY 2021; 32:075605. [PMID: 33252055 DOI: 10.1088/1361-6528/abbb4e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Metastable wurtzite crystal phases of conventional semiconductors comprise enormous potential for high-performance electro-optical devices, owed to their extended tunable direct band gap range. However, synthesizing these materials in good quality and beyond nanowire size constraints has remained elusive. In this work, the epitaxy of wurtzite InP microdisks and related geometries on insulator for advanced optical applications is explored. This is achieved by an elaborate combination of selective area growth of fins and a zipper-induced epitaxial lateral overgrowth, which enables co-integration of diversely shaped crystals at precise position. The grown material possesses high phase purity and excellent optical quality characterized by STEM and µ-PL. Optically pumped lasing at room temperature is achieved in microdisks with a lasing threshold of 365 µJ cm-2. Our platform could provide novel geometries for photonic applications.
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Affiliation(s)
| | - Svenja Mauthe
- IBM Research Zurich, Säumerstrasse 4, 8803, Rüschlikon, Switzerland
| | | | - Steffen Reidt
- IBM Research Zurich, Säumerstrasse 4, 8803, Rüschlikon, Switzerland
| | | | - Heinz Schmid
- IBM Research Zurich, Säumerstrasse 4, 8803, Rüschlikon, Switzerland
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13
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Isoscattering strings of concatenating graphs and networks. Sci Rep 2021; 11:1575. [PMID: 33452312 PMCID: PMC7810996 DOI: 10.1038/s41598-020-80950-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 12/30/2020] [Indexed: 11/08/2022] Open
Abstract
We identify and investigate isoscattering strings of concatenating quantum graphs possessing n units and 2n infinite external leads. We give an insight into the principles of designing large graphs and networks for which the isoscattering properties are preserved for \documentclass[12pt]{minimal}
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\begin{document}$$n \rightarrow \infty $$\end{document}n→∞. The theoretical predictions are confirmed experimentally using \documentclass[12pt]{minimal}
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\begin{document}$$n=2$$\end{document}n=2 units, four-leads microwave networks. In an experimental and mathematical approach our work goes beyond prior results by demonstrating that using a trace function one can address the unsettled until now problem of whether scattering properties of open complex graphs and networks with many external leads are uniquely connected to their shapes. The application of the trace function reduces the number of required entries to the \documentclass[12pt]{minimal}
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\begin{document}$$2n \times 2n $$\end{document}2n×2n scattering matrices \documentclass[12pt]{minimal}
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\begin{document}$${\hat{S}}$$\end{document}S^ of the systems to 2n diagonal elements, while the old measures of isoscattering require all \documentclass[12pt]{minimal}
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\begin{document}$$(2n)^2$$\end{document}(2n)2 entries. The studied problem generalizes a famous question of Mark Kac “Can one hear the shape of a drum?”, originally posed in the case of isospectral dissipationless systems, to the case of infinite strings of open graphs and networks.
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14
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Ta VD, Saxena D, Caixeiro S, Sapienza R. Flexible and tensile microporous polymer fibers for wavelength-tunable random lasing. NANOSCALE 2020; 12:12357-12363. [PMID: 32490495 DOI: 10.1039/d0nr02484h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Polymer micro-/nanofibers, due to their low-cost and mechanical flexibility, are attractive building blocks for developing lightweight and flexible optical circuits. They are also versatile photonic materials for making various optical resonators and lasers, such as microrings, networks and random lasers. In particular, for random lasing architectures, the demonstrations to-date have mainly relied on fiber bundles whose properties are hard to tune post-fabrication. Here, we demonstrate the successful implementation of an inverted photonic glass structure with monodisperse pores of 1.28 μm into polymer fibers with diameter ranging from 10 to 60 μm. By doping organic dye molecules into this structure, individual fibers can sustain random lasing under optical pulse excitation. The dependence of lasing characteristics, including lasing spectrum and lasing threshold on fiber diameter are investigated. It is found that the lasing emission red-shifts and the threshold decreases with increasing fiber diameter. Furthermore, owing to the mechanical flexibility, the lasing properties can be dynamically changed upon stretching, leading to a wavelength-tunability of 5.5 nm. Our work provides a novel architecture for random lasers which has the potential for lasing tunability and optical sensing.
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Affiliation(s)
- Van Duong Ta
- Department of Optical Devices, Le Quy Don Technical University, Hanoi 100000, Vietnam.
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15
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Fasano V, Laurita R, Moffa M, Gualandi C, Colombo V, Gherardi M, Zussman E, Vasilyev G, Persano L, Camposeo A, Focarete ML, Pisignano D. Enhanced Electrospinning of Active Organic Fibers by Plasma Treatment on Conjugated Polymer Solutions. ACS APPLIED MATERIALS & INTERFACES 2020; 12:26320-26329. [PMID: 32406678 PMCID: PMC7302505 DOI: 10.1021/acsami.0c02724] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 05/14/2020] [Indexed: 05/05/2023]
Abstract
Realizing active, light-emitting fibers made of conjugated polymers by the electrospinning method is generally challenging. Electrospinning of plasma-treated conjugated polymer solutions is here developed for the production of light-emitting microfibers and nanofibers. Active fibers from conjugated polymer solutions rapidly processed by a cold atmospheric argon plasma are electrospun in an effective way, and they show a smoother surface and bead-less morphology, as well as preserved optical properties in terms of absorption, emission, and photoluminescence quantum yield. In addition, the polarization of emitted light and more notably photon waveguiding along the length of individual fibers are remarkably enhanced by electrospinning plasma-treated solutions. These properties come from a synergetic combination of favorable intermolecular coupling in the solutions, increased order of macromolecules on the nanoscale, and resulting fiber morphology. Such findings make the coupling of the electrospinning method and cold atmospheric plasma processing on conjugated polymer solutions a highly promising and possibly general route to generate light-emitting and conductive micro- and nanostructures for organic photonics and electronics.
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Affiliation(s)
- Vito Fasano
- Dipartimento di
Matematica e Fisica “Ennio De Giorgi”, Università del Salento, via Arnesano, I-73100 Lecce, Italy
| | - Romolo Laurita
- Department of Industrial
Engineering (DIN), Università di
Bologna, Viale del Risorgimento
2, 40123 Bologna, Italy
- Advanced Mechanics and Materials-Interdepartmental Center, University of Bologna, Viale del Risorgimento 2, 40123 Bologna, Italy
| | - Maria Moffa
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
| | - Chiara Gualandi
- Advanced Mechanics and Materials-Interdepartmental Center, University of Bologna, Viale del Risorgimento 2, 40123 Bologna, Italy
- Chemistry Department “Giacomo Ciamician”
and INSTM UdR of Bologna, University of
Bologna, via Selmi 2, 40126 Bologna, Italy
| | - Vittorio Colombo
- Department of Industrial
Engineering (DIN), Università di
Bologna, Viale del Risorgimento
2, 40123 Bologna, Italy
- Advanced Mechanics and Materials-Interdepartmental Center, University of Bologna, Viale del Risorgimento 2, 40123 Bologna, Italy
| | - Matteo Gherardi
- Department of Industrial
Engineering (DIN), Università di
Bologna, Viale del Risorgimento
2, 40123 Bologna, Italy
- Advanced Mechanics and Materials-Interdepartmental Center, University of Bologna, Viale del Risorgimento 2, 40123 Bologna, Italy
| | - Eyal Zussman
- Department of Mechanical
Engineering, Technion − Israel Institute
of Technology, Haifa 32000, Israel
| | - Gleb Vasilyev
- Department of Mechanical
Engineering, Technion − Israel Institute
of Technology, Haifa 32000, Israel
| | - Luana Persano
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
| | - Andrea Camposeo
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
| | - Maria Letizia Focarete
- Chemistry Department “Giacomo Ciamician”
and INSTM UdR of Bologna, University of
Bologna, via Selmi 2, 40126 Bologna, Italy
- Health
Sciences and Technologies-Interdepartmental Center for Industrial
Research (HST-ICIR), University of Bologna, Via Tolara di Sopra 41/E, Ozzano Emilia I-40064, Italy
| | - Dario Pisignano
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy
- Dipartimento di Fisica, Università
di Pisa, Largo B. Pontecorvo
3, I-56127 Pisa, Italy
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16
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Controllable Polarization of Lasing Emission From a Polymer Microfiber Laser. Sci Rep 2019; 9:17017. [PMID: 31745157 PMCID: PMC6863847 DOI: 10.1038/s41598-019-53437-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/15/2019] [Indexed: 11/22/2022] Open
Abstract
Microlasers with controllable polarization of output emission are vital for on-chip optical communications, optical sensors and optical switches. In this work, we report a high quality (Q) factor, low-threshold polymer microfiber laser and the possibility of achieving laser emission with a desired polarization. The microfiber is fabricated by direct drawing from a dye-doped polymer solution and it can generate whispering gallery mode (WGM) lasing under optical pulse excitation. When the microfiber is pumped from the side with pumping direction perpendicular to the microfiber’s axis, the polarization direction of the output laser is found to be the same as that of the pump laser. Lasing emission with either transverse electric (TE) or transverse magnetic (TM) modes can be obtained and these two polarization states can be switched over by tuning the pumping laser. Furthermore, emission with both TE and TM modes can also be observed by changing the orientation of the microfiber relatively to pumping direction. Our finding provides an effective approach for achieving microlasers that have high Q lasing modes with anticipated polarization.
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17
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Abstract
The spatial formation of coherent random laser modes in strongly scattering disordered random media is a central feature in the understanding of the physics of random lasers. We derive a quantum field theoretical method for random lasing in disordered samples of complex amplifying Mie resonators which is able to provide self-consistently and free of any fit parameter the full set of transport characteristics at and above the laser phase transition. The coherence length and the correlation volume respectively is derived as an experimentally measurable scale of the phase transition at the laser threshold. We find that the process of stimulated emission in extended disordered arrangements of active Mie resonators is ultimately connected to time-reversal symmetric multiple scattering in the sense of photonic transport while the diffusion coefficient is finite. A power law is found for the random laser mode diameters in stationary state with increasing pump intensity.
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