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Silvestri M, Venturi M, Di Muzio M, Adhikary R, Ferrante C, Benassi P, Marini A. Harnessing collisional nonlinearity for enhanced harmonic generation by ultraviolet plasmonic nanoparticles. J Chem Phys 2024; 161:054111. [PMID: 39092943 DOI: 10.1063/5.0210865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 07/10/2024] [Indexed: 08/04/2024] Open
Abstract
We investigate the contribution of inelastic electron collisions to nonlinear (NL) dynamics in ultraviolet plasmonic nanoparticles, exploring their potential for harmonic generation. Employing the Landau weak coupling formalism to model radiation-driven electron dynamics in sodium and aluminum, we account for both electron-electron and electron-phonon scattering processes by a set of hydrodynamic equations, which we solve perturbatively to obtain third-order NL susceptibilities. Furthermore, we model high harmonic generation enhanced by localized surface plasmons in nanospheres composed of such poor metals, demonstrating their efficient operation for extreme ultraviolet generation. Our investigation reveals that plasmonic nanospheres composed of sodium and aluminum produce a large field intensity enhancement of ≃103-105, boosting the harmonic generation process. Our findings indicate that poor metals hold great promise for advanced extreme ultraviolet nano-sources with potential applications in nano-spectroscopy.
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Affiliation(s)
- Matteo Silvestri
- Department of Physical and Chemical Sciences, University of L'Aquila, Via Vetoio, 67100 L'Aquila, Italy
| | - Matteo Venturi
- Department of Physical and Chemical Sciences, University of L'Aquila, Via Vetoio, 67100 L'Aquila, Italy
| | - Mattia Di Muzio
- Department of Physical and Chemical Sciences, University of L'Aquila, Via Vetoio, 67100 L'Aquila, Italy
| | - Raju Adhikary
- Department of Physical and Chemical Sciences, University of L'Aquila, Via Vetoio, 67100 L'Aquila, Italy
| | - Carino Ferrante
- CNR-SPIN, c/o Dip.to di Scienze Fisiche e Chimiche, Via Vetoio, Coppito (L'Aquila) 67100, Italy
| | - Paola Benassi
- Department of Physical and Chemical Sciences, University of L'Aquila, Via Vetoio, 67100 L'Aquila, Italy
- CNR-SPIN, c/o Dip.to di Scienze Fisiche e Chimiche, Via Vetoio, Coppito (L'Aquila) 67100, Italy
| | - Andrea Marini
- Department of Physical and Chemical Sciences, University of L'Aquila, Via Vetoio, 67100 L'Aquila, Italy
- CNR-SPIN, c/o Dip.to di Scienze Fisiche e Chimiche, Via Vetoio, Coppito (L'Aquila) 67100, Italy
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2
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Ihalage A, Hao Y. Formula Graph Self-Attention Network for Representation-Domain Independent Materials Discovery. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2200164. [PMID: 35475548 PMCID: PMC9218748 DOI: 10.1002/advs.202200164] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 03/05/2022] [Indexed: 06/14/2023]
Abstract
The success of machine learning (ML) in materials property prediction depends heavily on how the materials are represented for learning. Two dominant families of material descriptors exist, one that encodes crystal structure in the representation and the other that only uses stoichiometric information with the hope of discovering new materials. Graph neural networks (GNNs) in particular have excelled in predicting material properties within chemical accuracy. However, current GNNs are limited to only one of the above two avenues owing to the little overlap between respective material representations. Here, a new concept of formula graph which unifies stoichiometry-only and structure-based material descriptors is introduced. A self-attention integrated GNN that assimilates a formula graph is further developed and it is found that the proposed architecture produces material embeddings transferable between the two domains. The proposed model can outperform some previously reported structure-agnostic models and their structure-based counterparts while exhibiting better sample efficiency and faster convergence. Finally, the model is applied in a challenging exemplar to predict the complex dielectric function of materials and nominate new substances that potentially exhibit epsilon-near-zero phenomena.
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Affiliation(s)
- Achintha Ihalage
- School of Electronic Engineering and Computer ScienceQueen Mary University of LondonMile End RdLondonE1 4NSUnited Kingdom
| | - Yang Hao
- School of Electronic Engineering and Computer ScienceQueen Mary University of LondonMile End RdLondonE1 4NSUnited Kingdom
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3
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Bruno V, DeVault C, Vezzoli S, Kudyshev Z, Huq T, Mignuzzi S, Jacassi A, Saha S, Shah YD, Maier SA, Cumming DRS, Boltasseva A, Ferrera M, Clerici M, Faccio D, Sapienza R, Shalaev VM. Negative Refraction in Time-Varying Strongly Coupled Plasmonic-Antenna-Epsilon-Near-Zero Systems. PHYSICAL REVIEW LETTERS 2020; 124:043902. [PMID: 32058792 DOI: 10.1103/physrevlett.124.043902] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Time-varying metasurfaces are emerging as a powerful instrument for the dynamical control of the electromagnetic properties of a propagating wave. Here we demonstrate an efficient time-varying metasurface based on plasmonic nano-antennas strongly coupled to an epsilon-near-zero (ENZ) deeply subwavelength film. The plasmonic resonance of the metal resonators strongly interacts with the optical ENZ modes, providing a Rabi level spitting of ∼30%. Optical pumping at frequency ω induces a nonlinear polarization oscillating at 2ω responsible for an efficient generation of a phase conjugate and a negative refracted beam with a conversion efficiency that is more than 4 orders of magnitude greater compared to the bare ENZ film. The introduction of a strongly coupled plasmonic system therefore provides a simple and effective route towards the implementation of ENZ physics at the nanoscale.
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Affiliation(s)
- V Bruno
- School of Physics and Astronomy, University of Glasgow, G12 8QQ Glasgow, United Kingdom
| | - C DeVault
- Purdue Quantum Science and Engineering Institute, Purdue University 1205 West State Street, West Lafayette, Indiana 47907, USA
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, Indiana 47907, USA
| | - S Vezzoli
- The Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2BW, United Kingdom
| | - Z Kudyshev
- Purdue Quantum Science and Engineering Institute, Purdue University 1205 West State Street, West Lafayette, Indiana 47907, USA
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, Indiana 47907, USA
| | - T Huq
- The Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2BW, United Kingdom
| | - S Mignuzzi
- The Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2BW, United Kingdom
| | - A Jacassi
- The Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2BW, United Kingdom
| | - S Saha
- Purdue Quantum Science and Engineering Institute, Purdue University 1205 West State Street, West Lafayette, Indiana 47907, USA
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, Indiana 47907, USA
| | - Y D Shah
- School of Physics and Astronomy, University of Glasgow, G12 8QQ Glasgow, United Kingdom
| | - S A Maier
- The Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2BW, United Kingdom
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maxilimians-Universitat München, 80539 München, Germany
| | - D R S Cumming
- School of Engineering, University of Glasgow, G12 8LT Glasgow, United Kingdom
| | - A Boltasseva
- Purdue Quantum Science and Engineering Institute, Purdue University 1205 West State Street, West Lafayette, Indiana 47907, USA
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, Indiana 47907, USA
| | - M Ferrera
- Institute of Photonics and Quantum Sciences, Heriot-Watt University, EH14 4AS Edinburgh, United Kingdom
| | - M Clerici
- School of Engineering, University of Glasgow, G12 8LT Glasgow, United Kingdom
| | - D Faccio
- School of Physics and Astronomy, University of Glasgow, G12 8QQ Glasgow, United Kingdom
| | - R Sapienza
- The Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2BW, United Kingdom
| | - V M Shalaev
- Purdue Quantum Science and Engineering Institute, Purdue University 1205 West State Street, West Lafayette, Indiana 47907, USA
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, Indiana 47907, USA
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Bello F, Page AF, Pusch A, Hamm JM, Donegan JF, Hess O. Combining ε-Near-Zero Behavior and Stopped Light Energy Bands for Ultra-Low Reflection and Reduced Dispersion of Slow Light. Sci Rep 2017; 7:8702. [PMID: 28821737 PMCID: PMC5562864 DOI: 10.1038/s41598-017-08342-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/11/2017] [Indexed: 11/09/2022] Open
Abstract
We investigate media which exhibits epsilon-near-zero (ENZ) behavior while simultaneously sustaining stopped light energy bands which contain multiple points of zero group velocity (ZGV). This allows the merging of state-of-the-art phenomena that was hitherto attainable in media that demonstrated these traits separately. Specifically, we demonstrate the existence of Ferrell-Berreman (FB) modes within frequency bands bounded by points of ZGV with the goal to improve the coupling efficiency and localization of light in the media. The FB mode is formed within a double layer, thin-film stack where at subwavelength thicknesses the structure exhibits a very low reflection due to ENZ behavior. In addition, the structure is engineered to promote a flattened frequency dispersion with a negative permittivity able to induce multiple points of ZGV. For proof-of-concept, we propose an oxide-semiconductor-oxide-insulator stack and discuss the useful optical properties that arise from combining both phenomena. A transfer matrix (TM) treatment is used to derive the reflectivity profile and dispersion curves. Results show the ability to reduce reflection below 0.05% in accordance with recent experimental data while simultaneously exciting a polariton mode exhibiting both reduced group velocity and group velocity dispersion (GVD).
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Affiliation(s)
- Frank Bello
- School of Physics and the Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland. .,Advanced Materials and Bioengineering Research (AMBER), Trinity College Dublin, Dublin 2, Ireland.
| | - A Freddie Page
- Blackett Laboratory, Department of Physics, Imperial College London, London, SW7 2AZ, UK
| | - Andreas Pusch
- Blackett Laboratory, Department of Physics, Imperial College London, London, SW7 2AZ, UK
| | - Joachim M Hamm
- Blackett Laboratory, Department of Physics, Imperial College London, London, SW7 2AZ, UK
| | - John F Donegan
- School of Physics and the Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.,Advanced Materials and Bioengineering Research (AMBER), Trinity College Dublin, Dublin 2, Ireland
| | - Ortwin Hess
- Blackett Laboratory, Department of Physics, Imperial College London, London, SW7 2AZ, UK
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Janaszek B, Tyszka-Zawadzka A, Szczepański P. Control of gain/absorption in tunable hyperbolic metamaterials. OPTICS EXPRESS 2017; 25:13153-13162. [PMID: 28788851 DOI: 10.1364/oe.25.013153] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 05/05/2017] [Indexed: 06/07/2023]
Abstract
In this paper, the possibility of shaping the gain/absorption spectrum in tunable hyperbolic metamaterial (THMM) composed of subsequent layers of graphene and active/passive material by external biasing is demonstrated. For the first time it has been shown that resonance transitions between different dispersion regimes, i.e., Type I HMM→elliptic, elliptic→Type II HMM, elliptic→Type I HMM, are accompanied by interesting optical effects, such as anisotropic effective gain/absorption enhancement or electromagnetic transparency, all controllable by external voltage. We believe that this kind of tunable metamaterial could lay the foundation for a new class of active/passive media with controllable gain/absorption or electromagnetic transparency.
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Ciattoni A, Marini A, Rizza C. All-optical modulation in wavelength-sized epsilon-near-zero media. OPTICS LETTERS 2016; 41:3102-3105. [PMID: 27367112 DOI: 10.1364/ol.41.003102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigate the interaction of two pulses (pump and probe) scattered by a nonlinear epsilon-near-zero (ENZ) slab whose thickness is comparable with the ENZ wavelength. We show that when the probe has a narrow spectrum localized around the ENZ wavelength, its transmission is dramatically affected by the intensity of the pump. Conversely, if the probe is not in the ENZ regime, its propagation is not noticeably affected by the pump. Such all-optical modulation is due to the oversensitive character of the ENZ regime, and it is so efficient that it even occurs in a wavelength thick slab.
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Caspani L, Kaipurath RPM, Clerici M, Ferrera M, Roger T, Kim J, Kinsey N, Pietrzyk M, Di Falco A, Shalaev VM, Boltasseva A, Faccio D. Enhanced Nonlinear Refractive Index in ε-Near-Zero Materials. PHYSICAL REVIEW LETTERS 2016; 116:233901. [PMID: 27341234 DOI: 10.1103/physrevlett.116.233901] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Indexed: 05/27/2023]
Abstract
New propagation regimes for light arise from the ability to tune the dielectric permittivity to extremely low values. Here, we demonstrate a universal approach based on the low linear permittivity values attained in the ε-near-zero (ENZ) regime for enhancing the nonlinear refractive index, which enables remarkable light-induced changes of the material properties. Experiments performed on Al-doped ZnO (AZO) thin films show a sixfold increase of the Kerr nonlinear refractive index (n_{2}) at the ENZ wavelength, located in the 1300 nm region. This in turn leads to ultrafast light-induced refractive index changes of the order of unity, thus representing a new paradigm for nonlinear optics.
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Affiliation(s)
- L Caspani
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - R P M Kaipurath
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - M Clerici
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
- School of Engineering, University of Glasgow, Glasgow G12 8LT, United Kingdom
| | - M Ferrera
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - T Roger
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - J Kim
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, Indiana 47907-2057, USA
| | - N Kinsey
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, Indiana 47907-2057, USA
| | - M Pietrzyk
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - A Di Falco
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - V M Shalaev
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, Indiana 47907-2057, USA
| | - A Boltasseva
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, Indiana 47907-2057, USA
| | - D Faccio
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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Marini A, García de Abajo FJ. Graphene-Based Active Random Metamaterials for Cavity-Free Lasing. PHYSICAL REVIEW LETTERS 2016; 116:217401. [PMID: 27284672 DOI: 10.1103/physrevlett.116.217401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Indexed: 06/06/2023]
Abstract
Manipulating and controlling the optical energy flow inside random media is a research frontier of photonics and the basis of novel laser designs. Here, we show that a metamaterial consisting of randomly dispersed graphene nanoflakes embedded within an optically pumped gain medium (rhodamine 6G) can operate as a cavity-free laser thanks to its extraordinarily low threshold for saturable absorption. The emitted light is self-organized into a well-determined spatial pattern, which depends on the graphene flake density and can be externally controlled through the optical pump. We provide different examples of tunable laser operation ranging from stable single-mode to chaoticlike behavior. Our metamaterial design holds great potential for the optical control of light amplification, as well as for the development of single-mode beam-engineered cavity-free lasers.
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Affiliation(s)
- A Marini
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - F J García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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