1
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Chen R, Li P. Guided spiraling phonon polaritons in rolled one-dimensional MoO 3 nanotubes. OPTICS EXPRESS 2023; 31:42995-43003. [PMID: 38178403 DOI: 10.1364/oe.502399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 08/31/2023] [Indexed: 01/06/2024]
Abstract
Polaritons in reduced-dimensional materials, such as nanowire, nanoribbon and rolled nanotube, usually provide novel avenues for manipulating electromagnetic fields at the nanoscale. Here, we theoretically propose and study hyperbolic phonon polaritons (HPhPs) with rolled one-dimensional molybdenum trioxide (MoO3) nanotube structure. We find that the HPhPs in rolled MoO3 nanotubes exhibit low propagation losses and tunable electromagnetic confinement along the rolled direction. By rolling the twisted bilayer MoO3, we successfully achieve a canalized phonon polaritons mode in the rolled nanotube, enabling their propagation in a spiraling manner along the nanotube. Our findings demonstrate the considerable potential of the rolled MoO3 nanotubes as promising platforms for various applications in light manipulation and nanophotonics circuits, including negative refraction, waveguiding and routing at the ultimate scale.
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2
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Cheng SW, Xu D, Su H, Baxter JM, Holtzman LN, Watanabe K, Taniguchi T, Hone JC, Barmak K, Delor M. Optical Imaging of Ultrafast Phonon-Polariton Propagation through an Excitonic Sensor. NANO LETTERS 2023; 23:9936-9942. [PMID: 37852205 DOI: 10.1021/acs.nanolett.3c02897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
Hexagonal boron nitride (hBN) hosts phonon polaritons (PhP), hybrid light-matter states that facilitate electromagnetic field confinement and exhibit long-range ballistic transport. Extracting the spatiotemporal dynamics of PhPs usually requires "tour de force" experimental methods such as ultrafast near-field infrared microscopy. Here, we leverage the remarkable environmental sensitivity of excitons in two-dimensional transition metal dichalcogenides to image PhP propagation in adjacent hBN slabs. Using ultrafast optical microscopy on monolayer WSe2/hBN heterostructures, we image propagating PhPs from 3.5 K to room temperature with subpicosecond and few-nanometer precision. Excitons in WSe2 act as transducers between visible light pulses and infrared PhPs, enabling visible-light imaging of PhP transport with far-field microscopy. We also report evidence of excitons in WSe2 copropagating with hBN PhPs over several micrometers. Our results provide new avenues for imaging polar excitations over a large frequency range with extreme spatiotemporal precision and new mechanisms to realize ballistic exciton transport at room temperature.
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Affiliation(s)
- Shan-Wen Cheng
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Ding Xu
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Haowen Su
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - James M Baxter
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Luke N Holtzman
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - James C Hone
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Katayun Barmak
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Milan Delor
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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3
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Calandrini E, Voronin K, Balci O, Barra-Burillo M, Bylinkin A, Shinde SM, Sharma S, Casanova F, Hueso LE, Chuvilin A, McAleese C, Conran BR, Wang X, Teo K, Volkov VS, Ferrari AC, Nikitin AY, Hillenbrand R. Near- and Far-Field Observation of Phonon Polaritons in Wafer-Scale Multilayer Hexagonal Boron Nitride Prepared by Chemical Vapor Deposition. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2302045. [PMID: 37441751 DOI: 10.1002/adma.202302045] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 06/10/2023] [Accepted: 07/12/2023] [Indexed: 07/15/2023]
Abstract
Polaritons in layered materials (LMs) are a promising platform to manipulate and control light at the nanometer scale. Thus, the observation of polaritons in wafer-scale LMs is critically important for the development of industrially relevant nanophotonics and optoelectronics applications. In this work, phonon polaritons (PhPs) in wafer-scale multilayer hexagonal boron nitride (hBN) grown by chemical vapor deposition are reported. By infrared nanoimaging, the PhPs are visualized, and PhP lifetimes of ≈0.6 ps are measured, comparable to that of micromechanically exfoliated multilayer hBN. Further, PhP nanoresonators are demonstrated. Their quality factors of ≈50 are about 0.7 times that of state-of-the-art devices based on exfoliated hBN. These results can enable PhP-based surface-enhanced infrared spectroscopy (e.g., for gas sensing) and infrared photodetector applications.
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Affiliation(s)
- Eugenio Calandrini
- CIC nanoGUNE BRTA, Tolosa Hiribidea, 76, Donostia-San Sebastián, 20018, Spain
| | - Kirill Voronin
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal, 4, Donostia-San Sebastián, 20018, Spain
| | - Osman Balci
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Ave, Cambridge, CB3 0FA, UK
| | - Maria Barra-Burillo
- CIC nanoGUNE BRTA, Tolosa Hiribidea, 76, Donostia-San Sebastián, 20018, Spain
| | - Andrei Bylinkin
- CIC nanoGUNE BRTA, Tolosa Hiribidea, 76, Donostia-San Sebastián, 20018, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal, 4, Donostia-San Sebastián, 20018, Spain
| | - Sachin M Shinde
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Ave, Cambridge, CB3 0FA, UK
| | - Subash Sharma
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Ave, Cambridge, CB3 0FA, UK
| | - Fèlix Casanova
- CIC nanoGUNE BRTA, Tolosa Hiribidea, 76, Donostia-San Sebastián, 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48009, Spain
| | - Luis E Hueso
- CIC nanoGUNE BRTA, Tolosa Hiribidea, 76, Donostia-San Sebastián, 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48009, Spain
| | - Andrei Chuvilin
- CIC nanoGUNE BRTA, Tolosa Hiribidea, 76, Donostia-San Sebastián, 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48009, Spain
| | - Clifford McAleese
- AIXTRON Ltd, Buckingway Business Park, Anderson Rd, Swavesey, Cambridge, CB24 4FQ, UK
| | - Ben R Conran
- AIXTRON Ltd, Buckingway Business Park, Anderson Rd, Swavesey, Cambridge, CB24 4FQ, UK
| | - Xiaochen Wang
- AIXTRON Ltd, Buckingway Business Park, Anderson Rd, Swavesey, Cambridge, CB24 4FQ, UK
| | - Kenneth Teo
- AIXTRON Ltd, Buckingway Business Park, Anderson Rd, Swavesey, Cambridge, CB24 4FQ, UK
| | | | - Andrea C Ferrari
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Ave, Cambridge, CB3 0FA, UK
| | - Alexey Y Nikitin
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal, 4, Donostia-San Sebastián, 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48009, Spain
| | - Rainer Hillenbrand
- CIC nanoGUNE BRTA, Tolosa Hiribidea, 76, Donostia-San Sebastián, 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48009, Spain
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4
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Zeng Y, Sun T, Chen R, Ma W, Yan Q, Lu D, Qin T, Hu C, Yang X, Li P. Optical nanoimaging of highly-confined phonon polaritons in atomically-thin nanoribbons of α-MoO 3. OPTICS EXPRESS 2023; 31:28010-28017. [PMID: 37710864 DOI: 10.1364/oe.492369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 05/29/2023] [Indexed: 09/16/2023]
Abstract
Phonon polaritons (PhPs), collective modes hybridizing photons with lattice vibrations in polar insulators, enable nanoscale control of light. In recent years, the exploration of in-plane anisotropic PhPs has yielded new levels of confinement and directional manipulation of nano-light. However, the investigation of in-plane anisotropic PhPs at the atomic layer limit is still elusive. Here, we report the optical nanoimaging of highly-confined phonon polaritons in atomically-thin nanoribbons of α-MoO3 (5 atomic layers). We show that narrow α-MoO3 nanoribbons as thin as a few atomic layers can support anisotropic PhPs modes with a high confinement ratio (∼133 times smaller wavelength than that of light). The anisotropic PhPs interference fringe patterns in atomic layers are tunable depending on the PhP wavelength via changing the illumination frequency. Moreover, spatial control over the PhPs interference patterns is also achieved by varying the nanostructures' shape or nanoribbon width of atomically-thin α-MoO3. Our work may serve as an empirical reference point for other anisotropic PhPs that approach the thickness limit and pave the way for applications such as atomically integrated nano-photonics and sensing.
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5
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He M, Hoogendoorn L, Dixit S, Pan Z, Lu G, Diaz-Granados K, Li D, Caldwell JD. Guided Polaritons along the Forbidden Direction in MoO 3 with Geometrical Confinement. NANO LETTERS 2023. [PMID: 37235534 DOI: 10.1021/acs.nanolett.3c00892] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Highly anisotropic materials show great promise for spatial control and the manipulation of polaritons. In-plane hyperbolic phonon polaritons (HPhPs) supported by α-phase molybdenum trioxide (MoO3) allow for wave propagation with a high directionality due to the hyperbola-shaped isofrequency contour (IFC). However, the IFC prohibits propagations along the [001] axis, hindering information or energy flow. Here, we illustrate a novel approach to manipulating the HPhP propagation direction. We experimentally demonstrate that geometrical confinement in the [100] axis can guide HPhPs along the forbidden direction with phase velocity becoming negative. We further developed an analytical model to provide insights into this transition. Moreover, as the guided HPhPs are formed in-plane, modal profiles were directly imaged to further expand our understanding of the formation of HPhPs. Our work reveals a possibility for manipulating HPhPs and paves the way for promising applications in metamaterials, nanophotonics, and quantum optics based on natural van der Waals materials.
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Affiliation(s)
- Mingze He
- Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37240, USA
| | - Levi Hoogendoorn
- Research Experience for Undergraduates (REU) program, Vanderbilt Institute for Nanoscale Science and Engineering (VINSE), Vanderbilt University, Nashville, Tennessee 37240, USA
- Integrated Science Program, Northwestern University, Evanston, Illinois 60208, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Saurabh Dixit
- Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37240, USA
| | - Zhiliang Pan
- Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37240, USA
| | - Guanyu Lu
- Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37240, USA
| | - Katja Diaz-Granados
- Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, Tennessee 37240, USA
| | - Deyu Li
- Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37240, USA
| | - Joshua D Caldwell
- Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37240, USA
- Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, Tennessee 37240, USA
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6
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Karanikolas V, Iwasaki T, Henzie J, Ikeda N, Yamauchi Y, Wakayama Y, Kuroda T, Watanabe K, Taniguchi T. Plasmon-Triggered Ultrafast Operation of Color Centers in Hexagonal Boron Nitride Layers. ACS OMEGA 2023; 8:14641-14647. [PMID: 37125116 PMCID: PMC10134455 DOI: 10.1021/acsomega.3c00512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 03/15/2023] [Indexed: 05/03/2023]
Abstract
High-quality emission centers in two-dimensional materials are promising components for future photonic and optoelectronic applications. Carbon-enriched hexagonal boron nitride (hBN:C) layers host atom-like color-center (CC) defects with strong and robust photoemission up to room temperature. Placing the hBN:C layers on top of Ag triangle nanoparticles (NPs) accelerates the decay of the CC defects down to 46 ps from their reference bulk value of 350 ps. The ultrafast decay is achieved due to the efficient excitation of the plasmon modes of the Ag NPs by the near field of the CCs. Simulations of the CC/Ag NP interaction show that higher Purcell values are expected, although the measured decay of the CCs is limited by the instrument response. The influence of the NP thickness on the Purcell factor of the CCs is analyzed. The ultrafast operation of the CCs in hBN:C layers paves the way for their use in demanding applications, such as single-photon emitters and quantum devices.
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Affiliation(s)
- Vasilios Karanikolas
- International
Center for Young Scientists (ICYS), National
Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takuya Iwasaki
- International
Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Joel Henzie
- JST-ERATO
Yamauchi Materials Space-Tectonics Project and International Center
for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, Tsukuba 305-0044, Japan
| | - Naoki Ikeda
- Research
Network and Facility Services Division, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Yusuke Yamauchi
- Australian
Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, Queensland 4072, Australia
- JST-ERATO
Yamauchi Materials Space-Tectonics Project and International Center
for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, Tsukuba 305-0044, Japan
| | - Yutaka Wakayama
- International
Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Kuroda
- Research
Center for Functional Materials, National
Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research
Center for Functional Materials, National
Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International
Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
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7
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Matveeva OG, Tresguerres-Mata AIF, Kirtaev RV, Voronin KV, Taboada-Gutiérrez J, Lanza C, Duan J, Martín-Sánchez J, Volkov VS, Alonso-González P, Nikitin AY. Twist-tunable polaritonic nanoresonators in a van der Waals crystal. NPJ 2D MATERIALS AND APPLICATIONS 2023; 7:31. [PMID: 38665481 PMCID: PMC11041695 DOI: 10.1038/s41699-023-00387-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 03/10/2023] [Indexed: 04/28/2024]
Abstract
Optical nanoresonators are key building blocks in various nanotechnological applications (e.g., spectroscopy) due to their ability to effectively confine light at the nanoscale. Recently, nanoresonators based on phonon polaritons (PhPs)-light coupled to lattice vibrations-in polar crystals (e.g., SiC, or h-BN) have attracted much attention due to their strong field confinement, high quality factors, and their potential to enhance the photonic density of states at mid-infrared (mid-IR) frequencies, where numerous molecular vibrations reside. Here, we introduce a new class of mid-IR nanoresonators that not only exhibit the extraordinary properties previously reported, but also incorporate a new degree of freedom: twist tuning, i.e., the possibility of controlling their spectral response by simply rotating the constituent material. To achieve this result, we place a pristine slab of the van der Waals (vdW) α-MoO3 crystal, which supports in-plane hyperbolic PhPs, on an array of metallic ribbons. This sample design based on electromagnetic engineering, not only allows the definition of α-MoO3 nanoresonators with low losses (quality factors, Q, up to 200), but also enables a broad spectral tuning of the polaritonic resonances (up to 32 cm-1, i.e., up to ~6 times their full width at half maximum, FWHM ~5 cm-1) by a simple in-plane rotation of the same slab (from 0 to 45°). These results open the door to the development of tunable and low-loss IR nanotechnologies, fundamental requirements for their implementation in molecular sensing, emission or photodetection applications.
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Affiliation(s)
- O. G. Matveeva
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Spain
| | | | - R. V. Kirtaev
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Spain
| | - K. V. Voronin
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Spain
| | - J. Taboada-Gutiérrez
- Department of Physics, University of Oviedo, 33006 Oviedo, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), 33940 El Entrego, Spain
| | - C. Lanza
- Department of Physics, University of Oviedo, 33006 Oviedo, Spain
| | - J. Duan
- Department of Physics, University of Oviedo, 33006 Oviedo, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), 33940 El Entrego, Spain
| | - J. Martín-Sánchez
- Department of Physics, University of Oviedo, 33006 Oviedo, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), 33940 El Entrego, Spain
| | - V. S. Volkov
- XPANCEO, Bayan Business Center, DIP, 607-0406 Dubai, UAE
| | - P. Alonso-González
- Department of Physics, University of Oviedo, 33006 Oviedo, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), 33940 El Entrego, Spain
| | - A. Y. Nikitin
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
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8
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Aghamiri NA, Hu G, Fali A, Zhang Z, Li J, Balendhran S, Walia S, Sriram S, Edgar JH, Ramanathan S, Alù A, Abate Y. Reconfigurable hyperbolic polaritonics with correlated oxide metasurfaces. Nat Commun 2022; 13:4511. [PMID: 35922424 PMCID: PMC9349304 DOI: 10.1038/s41467-022-32287-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
Polaritons enable subwavelength confinement and highly anisotropic flows of light over a wide spectral range, holding the promise for applications in modern nanophotonic and optoelectronic devices. However, to fully realize their practical application potential, facile methods enabling nanoscale active control of polaritons are needed. Here, we introduce a hybrid polaritonic-oxide heterostructure platform consisting of van der Waals crystals, such as hexagonal boron nitride (hBN) or alpha-phase molybdenum trioxide (α-MoO3), transferred on nanoscale oxygen vacancy patterns on the surface of prototypical correlated perovskite oxide, samarium nickel oxide, SmNiO3 (SNO). Using a combination of scanning probe microscopy and infrared nanoimaging techniques, we demonstrate nanoscale reconfigurability of complex hyperbolic phonon polaritons patterned at the nanoscale with high resolution. Hydrogenation and temperature modulation allow spatially localized conductivity modulation of SNO nanoscale patterns, enabling robust real-time modulation and nanoscale reconfiguration of hyperbolic polaritons. Our work paves the way towards nanoscale programmable metasurface engineering for reconfigurable nanophotonic applications. Phonon polaritons in anisotropic van der Waals materials enable subwavelength confinement and controllable flow of light at the nanoscale. Here, the authors exploit correlated perovskite oxide (SmNiO3) substrates with tunable conductivity to obtain real-time modulation and nanoscale reconfiguration of hyperbolic polaritons in hBN and α-MoO3 crystals.
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Affiliation(s)
| | - Guangwei Hu
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, 10031, USA.,Department of Electrical and Computer Engineering, National University of Singapore, Kent Ridge, Singapore, 117583, Singapore
| | - Alireza Fali
- Department of Physics and Astronomy, University of Georgia, Athens, GA, 30602, USA
| | - Zhen Zhang
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Jiahan Li
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KN, 66506, USA
| | | | - Sumeet Walia
- School of Engineering RMIT University Melbourne, Melbourne, VIC, Australia.,Functional Materials and Microsystems Research Group and the Micro Nano Research Facility RMIT University, Melbourne, VIC, Australia
| | - Sharath Sriram
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility RMIT University, Melbourne, VIC, Australia.,ARC Centre of Excellence for Transformative Meta-Optical Systems, RMIT University, Melbourne, VIC, Australia
| | - James H Edgar
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KN, 66506, USA
| | - Shriram Ramanathan
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Andrea Alù
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, 10031, USA.,Physics Program, Graduate Center, City University of New York, New York, NY, 10016, USA
| | - Yohannes Abate
- Department of Physics and Astronomy, University of Georgia, Athens, GA, 30602, USA.
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9
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Duan J, Alfaro-Mozaz FJ, Taboada-Gutiérrez J, Dolado I, Álvarez-Pérez G, Titova E, Bylinkin A, Tresguerres-Mata AIF, Martín-Sánchez J, Liu S, Edgar JH, Bandurin DA, Jarillo-Herrero P, Hillenbrand R, Nikitin AY, Alonso-González P. Active and Passive Tuning of Ultranarrow Resonances in Polaritonic Nanoantennas. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2104954. [PMID: 34964174 DOI: 10.1002/adma.202104954] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 12/23/2021] [Indexed: 06/14/2023]
Abstract
Optical nanoantennas are of great importance for photonic devices and spectroscopy due to their capability of squeezing light at the nanoscale and enhancing light-matter interactions. Among them, nanoantennas made of polar crystals supporting phonon polaritons (phononic nanoantennas) exhibit the highest quality factors. This is due to the low optical losses inherent in these materials, which, however, hinder the spectral tuning of the nanoantennas due to their dielectric nature. Here, active and passive tuning of ultranarrow resonances in phononic nanoantennas is realized over a wide spectral range (≈35 cm-1 , being the resonance linewidth ≈9 cm-1 ), monitored by near-field nanoscopy. To do that, the local environment of a single nanoantenna made of hexagonal boron nitride is modified by placing it on different polar substrates, such as quartz and 4H-silicon carbide, or covering it with layers of a high-refractive-index van der Waals crystal (WSe2 ). Importantly, active tuning of the nanoantenna polaritonic resonances is demonstrated by placing it on top of a gated graphene monolayer in which the Fermi energy is varied. This work presents the realization of tunable polaritonic nanoantennas with ultranarrow resonances, which can find applications in active nanooptics and (bio)sensing.
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Affiliation(s)
- Jiahua Duan
- Department of Physics, University of Oviedo, Oviedo, 33006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33940, Spain
| | | | - Javier Taboada-Gutiérrez
- Department of Physics, University of Oviedo, Oviedo, 33006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33940, Spain
| | - Irene Dolado
- CIC nanoGUNE, BRTA, Donostia-San Sebastian, 20018, Spain
| | - Gonzalo Álvarez-Pérez
- Department of Physics, University of Oviedo, Oviedo, 33006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33940, Spain
| | - Elena Titova
- Programmable Functional Materials Lab, Brain and Consciousness Research Center, Moscow, 121205, Russia
- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, 141701, Russia
| | - Andrei Bylinkin
- CIC nanoGUNE, BRTA, Donostia-San Sebastian, 20018, Spain
- Donostia International Physics Center (DIPC), Donostia-San Sebastian, 20018, Spain
| | - Ana Isabel F Tresguerres-Mata
- Department of Physics, University of Oviedo, Oviedo, 33006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33940, Spain
| | - Javier Martín-Sánchez
- Department of Physics, University of Oviedo, Oviedo, 33006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33940, Spain
| | - Song Liu
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, USA
| | - James H Edgar
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, USA
| | - Denis A Bandurin
- Department of Physics, Massachusetts Institute of Technology (MIT), Boston, MA, 02139, USA
| | - Pablo Jarillo-Herrero
- Department of Physics, Massachusetts Institute of Technology (MIT), Boston, MA, 02139, USA
| | - Rainer Hillenbrand
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48013, Spain
- CIC nanoGUNE, BRTA and Department of Electricity and Electronics, EHU/UPV, Donostia-San Sebastián, 20018, Spain
| | - Alexey Y Nikitin
- Donostia International Physics Center (DIPC), Donostia-San Sebastian, 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48013, Spain
| | - Pablo Alonso-González
- Department of Physics, University of Oviedo, Oviedo, 33006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33940, Spain
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10
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Interface nano-optics with van der Waals polaritons. Nature 2021; 597:187-195. [PMID: 34497390 DOI: 10.1038/s41586-021-03581-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 04/23/2021] [Indexed: 01/27/2023]
Abstract
Polaritons are hybrid excitations of matter and photons. In recent years, polaritons in van der Waals nanomaterials-known as van der Waals polaritons-have shown great promise to guide the flow of light at the nanoscale over spectral regions ranging from the visible to the terahertz. A vibrant research field based on manipulating strong light-matter interactions in the form of polaritons, supported by these atomically thin van der Waals nanomaterials, is emerging for advanced nanophotonic and opto-electronic applications. Here we provide an overview of the state of the art of exploiting interface optics-such as refractive optics, meta-optics and moiré engineering-for the control of van der Waals polaritons. This enhanced control over van der Waals polaritons at the nanoscale has not only unveiled many new phenomena, but has also inspired valuable applications-including new avenues for nano-imaging, sensing, on-chip optical circuitry, and potentially many others in the years to come.
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11
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Wu Y, Ou Q, Dong S, Hu G, Si G, Dai Z, Qiu CW, Fuhrer MS, Mokkapati S, Bao Q. Efficient and Tunable Reflection of Phonon Polaritons at Built-In Intercalation Interfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2008070. [PMID: 33998712 DOI: 10.1002/adma.202008070] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/29/2021] [Indexed: 06/12/2023]
Abstract
Phonon polaritons-light coupled to lattice vibrations-in polar van der Waals crystals offer unprecedented opportunities for controlling light at the nanoscale due to their anisotropic and ultralow-loss propagation. While their analog plasmon polaritons-light coupled to electron oscillations-have long been studied and exhibit interesting reflections at geometrical edges and electronic boundaries, whether phonon polaritons can be reflected by such barriers has been elusive. Here, the effective and tunable reflection of phonon polaritons at embedded interfaces formed in hydrogen-intercalated α-MoO3 flakes is elaborated upon. Without breaking geometrical continuity, such intercalation interfaces can reflect phonon polaritons with low losses, yielding the distinct phase changes of -0.8π and -0.3π associated with polariton propagation, high efficiency of 50%, and potential electrical tunability. The results point to a new approach to construct on-demand polariton reflectors, phase modulators, and retarders, which may be transplanted into building future polaritonic circuits using van der Waals crystals.
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Affiliation(s)
- Yingjie Wu
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - Qingdong Ou
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
- ARC Center of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, Victoria, 3800, Australia
| | - Shaohua Dong
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Singapore
| | - Guangwei Hu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Singapore
| | - Guangyuan Si
- Melbourne Center for Nanofabrication, Victorian Node of the Australian National Fabrication Facility, Clayton, Victoria, 3168, Australia
| | - Zhigao Dai
- Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, China
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Singapore
| | - Michael S Fuhrer
- ARC Center of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, Victoria, 3800, Australia
- School of Physics and Astronomy, Monash University, Clayton, Victoria, 3800, Australia
| | - Sudha Mokkapati
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - Qiaoliang Bao
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong SAR, China
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12
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Yao Z, Chen X, Wehmeier L, Xu S, Shao Y, Zeng Z, Liu F, Mcleod AS, Gilbert Corder SN, Tsuneto M, Shi W, Wang Z, Zheng W, Bechtel HA, Carr GL, Martin MC, Zettl A, Basov DN, Chen X, Eng LM, Kehr SC, Liu M. Probing subwavelength in-plane anisotropy with antenna-assisted infrared nano-spectroscopy. Nat Commun 2021; 12:2649. [PMID: 33976184 PMCID: PMC8113487 DOI: 10.1038/s41467-021-22844-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 03/29/2021] [Indexed: 02/03/2023] Open
Abstract
Infrared nano-spectroscopy based on scattering-type scanning near-field optical microscopy (s-SNOM) is commonly employed to probe the vibrational fingerprints of materials at the nanometer length scale. However, due to the elongated and axisymmetric tip shank, s-SNOM is less sensitive to the in-plane sample anisotropy in general. In this article, we report an easy-to-implement method to probe the in-plane dielectric responses of materials with the assistance of a metallic disk micro-antenna. As a proof-of-concept demonstration, we investigate here the in-plane phonon responses of two prototypical samples, i.e. in (100) sapphire and x-cut lithium niobate (LiNbO3). In particular, the sapphire in-plane vibrations between 350 cm-1 to 800 cm-1 that correspond to LO phonon modes along the crystal b- and c-axis are determined with a spatial resolution of < λ/10, without needing any fitting parameters. In LiNbO3, we identify the in-plane orientation of its optical axis via the phonon modes, demonstrating that our method can be applied without prior knowledge of the crystal orientation. Our method can be elegantly adapted to retrieve the in-plane anisotropic response of a broad range of materials, i.e. subwavelength microcrystals, van-der-Waals materials, or topological insulators.
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Affiliation(s)
- Ziheng Yao
- grid.36425.360000 0001 2216 9681Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY USA ,grid.184769.50000 0001 2231 4551Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
| | - Xinzhong Chen
- grid.36425.360000 0001 2216 9681Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY USA
| | - Lukas Wehmeier
- grid.4488.00000 0001 2111 7257Institute of Applied Physics, Technische Universität Dresden, Dresden, Germany ,grid.4488.00000 0001 2111 7257ct.qmat, Dresden-Würzburg Cluster of Excellence-EXC 2147, Technische Universität Dresden, Dresden, Germany
| | - Suheng Xu
- grid.36425.360000 0001 2216 9681Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY USA ,grid.21729.3f0000000419368729Department of Physics, Columbia University, New York, NY USA
| | - Yinming Shao
- grid.21729.3f0000000419368729Department of Physics, Columbia University, New York, NY USA
| | - Zimeng Zeng
- grid.12527.330000 0001 0662 3178State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
| | - Fanwei Liu
- grid.12527.330000 0001 0662 3178State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
| | - Alexander S. Mcleod
- grid.21729.3f0000000419368729Department of Physics, Columbia University, New York, NY USA
| | - Stephanie N. Gilbert Corder
- grid.184769.50000 0001 2231 4551Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
| | - Makoto Tsuneto
- grid.36425.360000 0001 2216 9681Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY USA
| | - Wu Shi
- grid.184769.50000 0001 2231 4551Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA ,grid.47840.3f0000 0001 2181 7878Department of Physics, University of California, Berkeley, CA USA ,grid.8547.e0000 0001 0125 2443Institute of Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai, China
| | - Zihang Wang
- grid.47840.3f0000 0001 2181 7878Department of Physics, University of California, Berkeley, CA USA
| | - Wenjun Zheng
- grid.36425.360000 0001 2216 9681Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY USA
| | - Hans A. Bechtel
- grid.184769.50000 0001 2231 4551Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
| | - G. L. Carr
- grid.202665.50000 0001 2188 4229National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY USA
| | - Michael C. Martin
- grid.184769.50000 0001 2231 4551Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
| | - Alex Zettl
- grid.184769.50000 0001 2231 4551Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA ,grid.47840.3f0000 0001 2181 7878Department of Physics, University of California, Berkeley, CA USA
| | - D. N. Basov
- grid.21729.3f0000000419368729Department of Physics, Columbia University, New York, NY USA
| | - Xi Chen
- grid.12527.330000 0001 0662 3178State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
| | - Lukas M. Eng
- grid.4488.00000 0001 2111 7257Institute of Applied Physics, Technische Universität Dresden, Dresden, Germany ,grid.4488.00000 0001 2111 7257ct.qmat, Dresden-Würzburg Cluster of Excellence-EXC 2147, Technische Universität Dresden, Dresden, Germany
| | - Susanne C. Kehr
- grid.4488.00000 0001 2111 7257Institute of Applied Physics, Technische Universität Dresden, Dresden, Germany
| | - Mengkun Liu
- grid.36425.360000 0001 2216 9681Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY USA ,grid.202665.50000 0001 2188 4229National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY USA
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13
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Feres FH, Mayer RA, Wehmeier L, Maia FCB, Viana ER, Malachias A, Bechtel HA, Klopf JM, Eng LM, Kehr SC, González JC, Freitas RO, Barcelos ID. Sub-diffractional cavity modes of terahertz hyperbolic phonon polaritons in tin oxide. Nat Commun 2021; 12:1995. [PMID: 33790286 PMCID: PMC8012705 DOI: 10.1038/s41467-021-22209-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 02/18/2021] [Indexed: 02/01/2023] Open
Abstract
Hyperbolic phonon polaritons have recently attracted considerable attention in nanophotonics mostly due to their intrinsic strong electromagnetic field confinement, ultraslow polariton group velocities, and long lifetimes. Here we introduce tin oxide (SnO2) nanobelts as a photonic platform for the transport of surface and volume phonon polaritons in the mid- to far-infrared frequency range. This report brings a comprehensive description of the polaritonic properties of SnO2 as a nanometer-sized dielectric and also as an engineered material in the form of a waveguide. By combining accelerator-based IR-THz sources (synchrotron and free-electron laser) with s-SNOM, we employed nanoscale far-infrared hyper-spectral-imaging to uncover a Fabry-Perot cavity mechanism in SnO2 nanobelts via direct detection of phonon-polariton standing waves. Our experimental findings are accurately supported by notable convergence between theory and numerical simulations. Thus, the SnO2 is confirmed as a natural hyperbolic material with unique photonic properties essential for future applications involving subdiffractional light traffic and detection in the far-infrared range.
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Affiliation(s)
- Flávio H Feres
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil
- Physics Department, Gleb Wataghin Physics Institute, University of Campinas (Unicamp), Campinas, SP, Brazil
| | - Rafael A Mayer
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil
- Physics Department, Gleb Wataghin Physics Institute, University of Campinas (Unicamp), Campinas, SP, Brazil
| | - Lukas Wehmeier
- Institute of Applied Physics, Technische Universität Dresden, Dresden, Germany
- ct.qmat, Dresden-Würzburg Cluster of Excellence-EXC 2147, Technische Universität Dresden, Dresden, Germany
| | - Francisco C B Maia
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil
| | - E R Viana
- Department of Physics, Universidade Tecnológica Federal do Paraná (UTFPR), Curitiba, PR, Brazil
| | - Angelo Malachias
- Department of Physics, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Hans A Bechtel
- Advanced Light Source (ALS), Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - J Michael Klopf
- Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - Lukas M Eng
- Institute of Applied Physics, Technische Universität Dresden, Dresden, Germany
- ct.qmat, Dresden-Würzburg Cluster of Excellence-EXC 2147, Technische Universität Dresden, Dresden, Germany
| | - Susanne C Kehr
- Institute of Applied Physics, Technische Universität Dresden, Dresden, Germany
| | - J C González
- Department of Physics, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Raul O Freitas
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil.
| | - Ingrid D Barcelos
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil.
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14
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He M, Halimi SI, Folland TG, Sunku SS, Liu S, Edgar JH, Basov DN, Weiss SM, Caldwell JD. Guided Mid-IR and Near-IR Light within a Hybrid Hyperbolic-Material/Silicon Waveguide Heterostructure. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2004305. [PMID: 33522035 DOI: 10.1002/adma.202004305] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 11/28/2020] [Indexed: 06/12/2023]
Abstract
Silicon waveguides have enabled large-scale manipulation and processing of near-infrared optical signals on chip. Yet, expanding the bandwidth of guided waves to other frequencies will further increase the functionality of silicon as a photonics platform. Frequency multiplexing by integrating additional architectures is one approach to the problem, but this is challenging to design and integrate within the existing form factor due to scaling with the free-space wavelength. This paper demonstrates that a hexagonal boron nitride (hBN)/silicon hybrid waveguide can simultaneously enable dual-band operation at both mid-infrared (6.5-7.0 µm) and telecom (1.55 µm) frequencies, respectively. The device is realized via the lithography-free transfer of hBN onto a silicon waveguide, maintaining near-infrared operation. In addition, mid-infrared waveguiding of the hyperbolic phonon polaritons (HPhPs) supported in hBN is induced by the index contrast between the silicon waveguide and the surrounding air underneath the hBN, thereby eliminating the need for deleterious etching of the hyperbolic medium. The behavior of HPhP waveguiding in both straight and curved trajectories is validated within an analytical waveguide theoretical framework. This exemplifies a generalizable approach based on integrating hyperbolic media with silicon photonics for realizing frequency multiplexing in on-chip photonic systems.
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Affiliation(s)
- Mingze He
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37212, USA
| | - Sami I Halimi
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, 37212, USA
| | - Thomas G Folland
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37212, USA
- Department of Physics and Astronomy, The University of Iowa, Iowa City, IA, 52242, USA
| | - Sai S Sunku
- Department of Physics, Columbia University, New York, NY, 10027, USA
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10027, USA
| | - Song Liu
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, USA
| | - James H Edgar
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, USA
| | - D N Basov
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10027, USA
| | - Sharon M Weiss
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, 37212, USA
| | - Joshua D Caldwell
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37212, USA
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, 37212, USA
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15
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Edge-oriented and steerable hyperbolic polaritons in anisotropic van der Waals nanocavities. Nat Commun 2020; 11:6086. [PMID: 33257664 PMCID: PMC7705012 DOI: 10.1038/s41467-020-19913-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 10/30/2020] [Indexed: 12/20/2022] Open
Abstract
Highly confined and low-loss polaritons are known to propagate isotropically over graphene and hexagonal boron nitride in the plane, leaving limited degrees of freedom in manipulating light at the nanoscale. The emerging family of biaxial van der Waals materials, such as α-MoO3 and V2O5, support exotic polariton propagation, as their auxiliary optical axis is in the plane. Here, exploiting this strong in-plane anisotropy, we report edge-tailored hyperbolic polaritons in patterned α-MoO3 nanocavities via real-space nanoimaging. We find that the angle between the edge orientation and the crystallographic direction significantly affects the optical response, and can serve as a key tuning parameter in tailoring the polaritonic patterns. By shaping α-MoO3 nanocavities with different geometries, we observe edge-oriented and steerable hyperbolic polaritons as well as forbidden zones where the polaritons detour. The lifetime and figure of merit of the hyperbolic polaritons can be regulated by the edge aspect ratio of nanocavity.
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