1
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Niemann R, Mueller NS, Wasserroth S, Lu G, Wolf M, Caldwell JD, Paarmann A. Spectroscopic and Interferometric Sum-Frequency Imaging of Strongly Coupled Phonon Polaritons in SiC Metasurfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2312507. [PMID: 38895889 DOI: 10.1002/adma.202312507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 06/07/2024] [Indexed: 06/21/2024]
Abstract
Phonon polaritons enable waveguiding and localization of infrared light with extreme confinement and low losses. The spatial propagation and spectral resonances of such polaritons are usually probed with complementary techniques such as near-field optical microscopy and far-field reflection spectroscopy. Here, infrared-visible sum-frequency spectro-microscopy is introduced as a tool for spectroscopic imaging of phonon polaritons. The technique simultaneously provides sub-wavelength spatial resolution and highly-resolved spectral resonance information. This is implemented by resonantly exciting polaritons using a tunable infrared laser and wide-field microscopic detection of the upconverted light. The technique is employed to image hybridization and strong coupling of localized and propagating surface phonon polaritons in a metasurface of SiC micropillars. Spectro-microscopy allows to measure the polariton dispersion simultaneously in momentum space by angle-dependent resonance imaging, and in real space by polariton interferometry. Notably, it is possible to directly image how strong coupling affects the spatial localization of polaritons, inaccessible with conventional spectroscopic techniques. The formation of edge states is observed at excitation frequencies where strong coupling prevents polariton propagation into the metasurface. The technique is applicable to the wide range of polaritonic materials with broken inversion symmetry and can be used as a fast and non-perturbative tool to image polariton hybridization and propagation.
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Affiliation(s)
- Richarda Niemann
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Niclas S Mueller
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Sören Wasserroth
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Guanyu Lu
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
- Present address: Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Martin Wolf
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Joshua D Caldwell
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
- Interdisciplinary Materials Science Graduate Program, Vanderbilt University, Nashville, TN 37235, USA
| | - Alexander Paarmann
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
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2
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Bondarev IV, Pugh MD, Rodriguez-Lopez P, Woods LM, Antezza M. Confinement-induced nonlocality and casimir force in transdimensional systems. Phys Chem Chem Phys 2023; 25:29257-29265. [PMID: 37874297 DOI: 10.1039/d3cp03706a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
We study within the framework of the Lifshitz theory the long-range Casimir force for in-plane isotropic and anisotropic free-standing transdimensional material slabs. In the former case, we show that the confinement-induced nonlocality not only weakens the attraction of ultrathin slabs but also changes the distance dependence of the material-dependent correction to the Casimir force to go as contrary to the ∼1/l dependence of that of the local Lifshitz force. In the latter case, we use closely packed array of parallel aligned single-wall carbon nanotubes in a dielectric layer of finite thickness to demonstrate strong orientational anisotropy and crossover behavior for the inter-slab attractive force in addition to its reduction with decreasing slab thickness. We give physical insight as to why such a pair of ultrathin slabs prefers to stick together in the perpendicularly oriented manner, rather than in the parallel relative orientation as one would customarily expect.
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Affiliation(s)
- Igor V Bondarev
- Department of Mathematics & Physics, North Carolina Central University, Durham, NC 27707, USA.
| | - Michael D Pugh
- Department of Mathematics & Physics, North Carolina Central University, Durham, NC 27707, USA.
| | - Pablo Rodriguez-Lopez
- Área de Electromagnetismo and Grupo Interdisciplinar de Sistemas Complejos (GISC), Universidad Rey Juan Carlos, 28933 Móstoles, Madrid, Spain
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-University of Montpellier, F-34095 Montpellier, France
| | - Lilia M Woods
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Mauro Antezza
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-University of Montpellier, F-34095 Montpellier, France
- Institut Universitaire de France, 1 rue Descartes, F-75231 Paris Cedex 05, France
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3
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Ma TT, Liu YQ, Yu CS. Release of virtual photon and phonon pairs from qubit-plasmon-phonon ultrastrong coupling system. OPTICS EXPRESS 2023; 31:30832-30846. [PMID: 37710617 DOI: 10.1364/oe.493549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/23/2023] [Indexed: 09/16/2023]
Abstract
The most important difference between ultrastrong and non-ultrastrong coupling regimes is that the ground state contains excitations. We consider a qubit-plasmon-phonon ultrastrong coupling (USC) system with a three-level atom coupled to the photon and phonon via its upper two energy levels and show that spontaneous emission of the atom from its intermediate to its ground state produces photon and phonon pairs. It is shown that the current system can produce a strong photon/phonon stream and the atom-phonon coupling plays the active role, which ensures the experimental detection. The emission spectrum and various high-order correlation functions confirm the generation of the pairs of photons and phonons. Our study has important implications for future research on virtual photon and phonon pairs creation in the ground state of the USC regime.
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4
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He M, Nolen JR, Nordlander J, Cleri A, Lu G, Arnaud T, McIlwaine NS, Diaz-Granados K, Janzen E, Folland TG, Edgar JH, Maria JP, Caldwell JD. Coupled Tamm Phonon and Plasmon Polaritons for Designer Planar Multiresonance Absorbers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209909. [PMID: 36843308 DOI: 10.1002/adma.202209909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/13/2023] [Indexed: 05/19/2023]
Abstract
Wavelength-selective absorbers (WS-absorbers) are of interest for various applications, including chemical sensing and light sources. Lithography-free fabrication of WS-absorbers can be realized via Tamm plasmon polaritons (TPPs) supported by distributed Bragg reflectors (DBRs) on plasmonic materials. While multifrequency and nearly arbitrary spectra can be realized with TPPs via inverse design algorithms, demanding and thick DBRs are required for high quality-factors (Q-factors) and/or multiband TPP-absorbers, increasing the cost and reducing fabrication error tolerance. Here, high Q-factor multiband absorption with limited DBR layers (3 layers) is experimentally demonstrated by Tamm hybrid polaritons (THPs) formed by coupling TPPs and Tamm phonon polaritons when modal frequencies are overlapped. Compared to the TPP component, the Q-factors of THPs are improved twofold, and the angular broadening is also reduced twofold, facilitating applications where narrow-band and nondispersive WS-absorbers are needed. Moreover, an open-source algorithm is developed to inversely design THP-absorbers consisting of anisotropic media and exemplify that the modal frequencies can be assigned to desirable positions. Furthermore, it is demonstrated that inversely designed THP-absorbers can realize same spectral resonances with fewer DBR layers than a TPP-absorber, thus reducing the fabrication complexity and enabling more cost-effective, lithography-free, wafer-scale WS-absorberss for applications such as free-space communications and gas sensing.
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Affiliation(s)
- Mingze He
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37240, USA
| | - Joshua Ryan Nolen
- Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, TN, 37240, USA
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, 10031, USA
| | - Josh Nordlander
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania, PA, 16802, USA
| | - Angela Cleri
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania, PA, 16802, USA
| | - Guanyu Lu
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37240, USA
| | - Thiago Arnaud
- Department of Physics, University of Florida, Gainesville, FL, 32611, USA
- Research Experience for Undergraduates (REU) program, Vanderbilt Institute for Nanoscale Science and Engineering (VINSE), Nashville, TN, 37240, USA
| | - Nathaniel S McIlwaine
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania, PA, 16802, USA
| | - Katja Diaz-Granados
- Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, TN, 37240, USA
| | - Eli Janzen
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, USA
| | - Thomas G Folland
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37240, USA
- Department of Physics and Astronomy, The University of Iowa, Iowa City, IA, 52242, USA
| | - James H Edgar
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, USA
| | - Jon-Paul Maria
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania, PA, 16802, USA
| | - Joshua D Caldwell
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37240, USA
- Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, TN, 37240, USA
- Sensorium Technological Laboratories, Nashville, TN, 37205, USA
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5
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Choudhary S, Iqbal S, Karimi M, Reshef O, Alam MZ, Boyd RW. Strongly Coupled Plasmon Polaritons in Gold and Epsilon-Near-Zero Bifilms. ACS PHOTONICS 2023; 10:162-169. [PMID: 36691428 PMCID: PMC9853859 DOI: 10.1021/acsphotonics.2c01412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Indexed: 06/17/2023]
Abstract
Epsilon-near-zero (ENZ) polaritons in a thin transparent conducting-oxide film exhibit a significant electric field enhancement and localization within the film at frequencies close to their plasma frequency, but do not propagate. Meanwhile, plasmon polariton modes in thin metallic films can propagate for several microns, but are more loosely confined in the metal. Here, we propose a strongly coupled bilayered structure of a thin gold film on a thin indium tin oxide (ITO) film that supports hybrid polariton modes. We experimentally characterize the dispersion of these modes and show that they have propagation lengths of 4-8 μm while retaining mode confinement greater than that of the polariton in gold films by nearly an order of magnitude. We study the tunability of this coupling strength by varying the thickness of the ITO film and show that ultrastrong coupling is possible at certain thicknesses. The unusual linear and nonlinear optical properties of ITO at ENZ frequencies make these bifilms useful for the active tuning of strong coupling, ultrafast switching, and enhanced nonlinear interactions at near-infrared frequencies.
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Affiliation(s)
- Saumya Choudhary
- Institute
of Optics, University of Rochester, Rochester, New York14627, United States
| | - Saleem Iqbal
- Institute
of Optics, University of Rochester, Rochester, New York14627, United States
| | - Mohammad Karimi
- Department
of Physics, University of Ottawa, Ottawa, OntarioK1N 6N5, Canada
| | - Orad Reshef
- Department
of Physics, University of Ottawa, Ottawa, OntarioK1N 6N5, Canada
| | - M. Zahirul Alam
- Department
of Physics, University of Ottawa, Ottawa, OntarioK1N 6N5, Canada
| | - Robert W. Boyd
- Institute
of Optics, University of Rochester, Rochester, New York14627, United States
- Department
of Physics, University of Ottawa, Ottawa, OntarioK1N 6N5, Canada
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6
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Hu Y, Zhang BY, Haque F, Ren G, Ou JZ. Plasmonic metal oxides and their biological applications. MATERIALS HORIZONS 2022; 9:2288-2324. [PMID: 35770972 DOI: 10.1039/d2mh00263a] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Metal oxides modified with dopants and defects are an emerging class of novel materials supporting the localized surface plasmon resonance across a wide range of optical wavelengths, which have attracted tremendous research interest particularly in biological applications in the past decade. Compared to conventional noble metal-based plasmonic materials, plasmonic metal oxides are particularly favored for their cost efficiency, flexible plasmonic properties, and improved biocompatibility, which can be important to accelerate their practical implementation. In this review, we first explicate the origin of plasmonics in dopant/defect-enabled metal oxides and their associated tunable localized surface plasmon resonance through the conventional Mie-Gans model. The research progress of dopant incorporation and defect generation in metal oxide hosts, including both in situ and ex situ approaches, is critically discussed. The implementation of plasmonic metal oxides in biological applications in terms of therapy, imaging, and sensing is summarized, in which the uniqueness of dopant/defect-driven plasmonics for inducing novel functionalities is particularly emphasized. This review may provide insightful guidance for developing next-generation plasmonic devices for human health monitoring, diagnosis and therapy.
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Affiliation(s)
- Yihong Hu
- School of Engineering, RMIT University, Melbourne, Victoria, 3000, Australia.
| | - Bao Yue Zhang
- School of Engineering, RMIT University, Melbourne, Victoria, 3000, Australia.
- School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia
| | - Farjana Haque
- School of Engineering, RMIT University, Melbourne, Victoria, 3000, Australia.
| | - Guanghui Ren
- School of Engineering, RMIT University, Melbourne, Victoria, 3000, Australia.
| | - Jian Zhen Ou
- School of Engineering, RMIT University, Melbourne, Victoria, 3000, Australia.
- School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, China
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7
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Lu G, Gubbin CR, Nolen JR, Folland TG, Diaz-Granados K, Kravchenko II, Spencer JA, Tadjer MJ, Glembocki OJ, De Liberato S, Caldwell JD. Collective Phonon-Polaritonic Modes in Silicon Carbide Subarrays. ACS NANO 2022; 16:963-973. [PMID: 34957830 DOI: 10.1021/acsnano.1c08557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Localized surface phonon polaritons (LSPhPs) can be implemented to engineer light-matter interactions through nanoscale patterning for a range of midinfrared application spaces. However, the polar material systems studied to date have mainly focused on simple designs featuring a single element in the periodic unit cell. Increasing the complexity of the unit cell can serve to modify the resonant near-fields and intra- and inter-unit-cell coupling as well as to dictate spectral tuning in the far-field. In this work, we exploit more complicated unit-cell structures to realize LSPhP modes with additional degrees of design freedom, which are largely unexplored. Collectively excited LSPhP modes with distinctly symmetric and antisymmetric near-fields are supported in these subarray designs, which are based on nanopillars that are scaled by the number of subarray elements to ensure a constant unit-cell size. Moreover, we observe an anomalous mode-matching of the collective symmetric mode in our fabricated subarrays that is robust to changing numbers of pillars within the subarrays as well as to defects intentionally introduced in the form of missing pillars. This work therefore illustrates the hierarchical design of tailored LSPhP resonances and modal near-field profiles simultaneously for a variety of IR applications such as surface-enhanced spectroscopies and biochemical sensing.
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Affiliation(s)
- Guanyu Lu
- Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Christopher R Gubbin
- School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - J Ryan Nolen
- Interdisciplinary Materials Science, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Thomas G Folland
- School of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Katja Diaz-Granados
- Interdisciplinary Materials Science, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Ivan I Kravchenko
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Joseph A Spencer
- US Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Marko J Tadjer
- US Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Orest J Glembocki
- Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Simone De Liberato
- School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Joshua D Caldwell
- Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
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8
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Grasseschi D, Bahamon DA, Maia FCB, Barcelos ID, Freitas RO, de Matos CJS. Van der Waals materials as dielectric layers for tailoring the near-field photonic response of surfaces. OPTICS EXPRESS 2022; 30:255-264. [PMID: 35201204 DOI: 10.1364/oe.445066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
Epsilon near-zero photonics and surface polariton nanophotonics have become major fields within optics, leading to unusual and enhanced light-matter interaction. Specific dielectric responses are required in both cases, which can be achieved, e.g., via operation near a material's electronic or phononic resonance. However, this condition restricts operation to a specific, narrow frequency range. It has been shown that using a thin dielectric layer can adjust the dielectric response of a surface and, therefore, the operating frequency for achieving specific photonic excitations. Here, we show that a surface's optical properties can be tuned via the deposition/transference of ultra-thin layered van der Waals (vdW) crystals, the thicknesses of which can easily be adjusted to provide the desired response. In particular, we experimentally and theoretically show that the surface phonon resonance of a silica surface can be tuned by ∼50 cm-1 through the simple deposition of nanometer-thick exfoliated flakes of black phosphorus. The surface properties were probed by infrared nanospectroscopy, and results show a close agreement with the theory. The black phosphorus-silica layered structure effectively acts as a surface with a tunable effective dielectric constant that presents an infrared response dependent on the black phosphorus thickness. In contrast, with a lower dielectric constant, hexagonal boron nitride does not significantly tune the silica surface phonon polariton. Our approach also applies to epsilon near-zero surfaces, as theoretically shown, and to polaritonic surfaces operating at other optical ranges.
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9
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Tomko JA, Runnerstrom EL, Wang YS, Chu W, Nolen JR, Olson DH, Kelley KP, Cleri A, Nordlander J, Caldwell JD, Prezhdo OV, Maria JP, Hopkins PE. Long-lived modulation of plasmonic absorption by ballistic thermal injection. NATURE NANOTECHNOLOGY 2021; 16:47-51. [PMID: 33169011 DOI: 10.1038/s41565-020-00794-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 10/13/2020] [Indexed: 06/11/2023]
Abstract
Light-matter interactions that induce charge and energy transfer across interfaces form the foundation for photocatalysis1,2, energy harvesting3 and photodetection4, among other technologies. One of the most common mechanisms associated with these processes relies on carrier injection. However, the exact role of the energy transport associated with this hot-electron injection remains unclear. Plasmon-assisted photocatalytic efficiencies can improve when intermediate insulation layers are used to inhibit the charge transfer5,6 or when off-resonance excitations are employed7, which suggests that additional energy transport and thermal effects could play an explicit role even if the charge transfer is inhibited8. This provides an additional interfacial mechanism for the catalytic and plasmonic enhancement at interfaces that moves beyond the traditionally assumed physical charge injection9-12. In this work, we report on a series of ultrafast plasmonic measurements that provide a direct measure of electronic distributions, both spatially and temporally, after the optical excitation of a metal/semiconductor heterostructure. We explicitly demonstrate that in cases of strong non-equilibrium, a novel energy transduction mechanism arises at the metal/semiconductor interface. We find that hot electrons in the metal contact transfer their energy to pre-existing free electrons in the semiconductor, without an equivalent spatiotemporal transfer of charge. Further, we demonstrate that this ballistic thermal injection mechanism can be utilized as a unique means to modulate plasmonic interactions. These experimental results are well-supported by both rigorous multilayer optical modelling and first-principle ab initio calculations.
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Affiliation(s)
- John A Tomko
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, USA
| | - Evan L Runnerstrom
- Army Research Office, CCDC US Army Research Laboratory, Research Triangle Park, NC, USA
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, USA
| | - Yi-Siang Wang
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, USA
| | - Weibin Chu
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, USA
| | - Joshua R Nolen
- Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, TN, USA
| | - David H Olson
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, USA
| | - Kyle P Kelley
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, USA
| | - Angela Cleri
- Department of Materials Science and Engineering, Pennsylvania State University, State College, PA, USA
| | - Josh Nordlander
- Department of Materials Science and Engineering, Pennsylvania State University, State College, PA, USA
| | - Joshua D Caldwell
- Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, TN, USA
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, USA
| | - Jon-Paul Maria
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, USA
- Department of Materials Science and Engineering, Pennsylvania State University, State College, PA, USA
| | - Patrick E Hopkins
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, USA.
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, USA.
- Department of Physics, University of Virginia, Charlottesville, VA, USA.
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10
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Reddy IVAK, Jornet JM, Baev A, Prasad PN. Extreme local field enhancement by hybrid epsilon-near-zero-plasmon mode in thin films of transparent conductive oxides. OPTICS LETTERS 2020; 45:5744-5747. [PMID: 33057274 DOI: 10.1364/ol.402647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/14/2020] [Indexed: 06/11/2023]
Abstract
Epsilon-near-zero (ENZ) materials display unique properties, and among them, large local field enhancement at ENZ frequency is of particular interest for many potential applications. In this Letter, we introduce the concept that a combination of epsilon-near-zero and surface plasmon polariton modes can be excited over an interface between a dielectric and a single ENZ layer in a specific frequency region, which can lead to extreme enhancement of local electric field. We demonstrate it with a systematic numerical simulation using finite element analysis and consider two configurations (Kretschmann configuration and a grating configuration), where an indium tin oxide (ITO) layer is sandwiched between two dielectric slabs. We confirm the formation of a hybrid mode at the ITO-dielectric interface at the wavelength of ENZ, as the ITO layer thickness reduces. The hybrid mode provides both high confinement and long propagation distance, which makes it more attractive for many applications than just a pure ENZ mode.
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11
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Gibbs SL, Dean C, Saad J, Tandon B, Staller CM, Agrawal A, Milliron DJ. Dual-Mode Infrared Absorption by Segregating Dopants within Plasmonic Semiconductor Nanocrystals. NANO LETTERS 2020; 20:7498-7505. [PMID: 32959661 DOI: 10.1021/acs.nanolett.0c02992] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
When aliovalent dopants are sufficiently segregated to the core or near the surface of semiconductor nanocrystals, charge carriers donated by the dopants are also segregated to the core or near the surface, respectively. In Sn-doped indium oxide nanocrystals, we find that this contrast in free charge carrier concentration creates a core and shell with differing dielectric properties and results in two distinctly observable plasmonic extinction peaks. The trends in this dual-mode optical response with shell growth differ from core/shell nanoparticles composed of traditional plasmonic metals such as Au and Ag. We developed a model employing a core/shell effective medium approximation that can fit the dual-mode spectra and explain the trends in the extinction response. Lastly, we show that dopant segregation can improve sensitivity of plasmon spectra to changes in refractive index of the surrounding environment.
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Affiliation(s)
- Stephen L Gibbs
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Christopher Dean
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Joey Saad
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Bharat Tandon
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Corey M Staller
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Ankit Agrawal
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
- The Molecular Foundry, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Delia J Milliron
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
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12
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Khan I, Fang Z, Palei M, Lu J, Nordin L, Simmons EL, Dominguez O, Islam SM, Xing HG, Jena D, Podolskiy VA, Wasserman D, Hoffman AJ. Engineering the Berreman mode in mid-infrared polar materials. OPTICS EXPRESS 2020; 28:28590-28599. [PMID: 32988126 DOI: 10.1364/oe.401733] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/27/2020] [Indexed: 06/11/2023]
Abstract
We demonstrate coupling to and control over the broadening and dispersion of a mid-infrared leaky mode, known as the Berreman mode, in samples with different dielectric environments. We fabricate subwavelength films of AlN, a mid-infrared epsilon-near-zero material that supports the Berreman mode, on materials with a weakly negative permittivity, strongly negative permittivity, and positive permittivity. Additionally, we incorporate ultra-thin AlN layers into a GaN/AlN heterostructure, engineering the dielectric environment above and below the AlN. In each of the samples, coupling to the Berreman mode is observed in angle-dependent reflection measurements at wavelengths near the longitudinal optical phonon energy. The measured dispersion of the Berreman mode agrees well with numerical modes. Differences in the dispersion and broadening for the different materials is quantified, including a 13 cm-1 red-shift in the energy of the Berreman mode for the heterostructure sample.
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13
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Sachet E, Aspnes DE, Maria JP, Franzen S. Critical Test of the Interaction of Surface Plasmon Resonances with Molecular Vibrational Transitions. J Phys Chem A 2020; 124:1744-1753. [PMID: 32040317 DOI: 10.1021/acs.jpca.9b10835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We determine the infrared absorption spectra of a gas due to evanescent plasmonic electromagnetic fields in a system where surface interactions (physisorption and chemisorption) are demonstrably negligible. The plasmonic host material, the degenerate semiconductor CdO:Dy, has high mobility (366-450 cm2/(V s)) and carrier density ((0.6-3.5) × 1020 cm-3), and therefore supports low-loss surface plasmon resonances in the mid-IR. This high-mobility layer gives the highest resolution observed in a plasmonic conducting material in the infrared, higher than that of gold and rivaling that of silver. The high resolution permits a new understanding of the nature of the interaction of emerging fields with molecular transitions. Using different carrier concentrations, the resonance condition of the surface plasmon polariton (SPP) frequency (ωSPP) and N2O vibrational absorption spectral frequency (ωN2O) can be controlled, thereby allowing a critical test of field-molecule interactions. Experiment and theory both indicate a dispersive N2O line shape for ωSPP < ωN2O, an absorptive line shape for ωSPP < ωN2O, and an abrupt change between the two when the resonance condition ωSPP < ωN2O is reached. A first-order expansion of the Airy equation describes this behavior analytically. The SPP surface enhancement is 6.8 ± 0.5 on-resonance, lower than enhancements observed in other systems, but in agreement with recent quantitative reports of surface enhanced infrared reflection absorption spectroscopy (SEIRA). Our results show that interactions of infrared SPPs with molecular vibrations are in the weak coupling limit, and that enhancements comparable those reported for noble metals can be achieved.
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Affiliation(s)
- Edward Sachet
- Third Floor Materials, Inc., Raleigh, North Carolina 27603, United States
| | - D E Aspnes
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - J-P Maria
- Department of Materials Science, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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Hu F, Jia W, Meng Y, Gong M, Yang Y. High-contrast optical switching using an epsilon-near-zero material coupled to a Bragg microcavity. OPTICS EXPRESS 2019; 27:26405-26414. [PMID: 31674523 DOI: 10.1364/oe.27.026405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 05/13/2019] [Indexed: 06/10/2023]
Abstract
Epsilon-near-zero (ENZ) materials have recently been suggested as excellent candidates for constructing all-optical and electro-optical switches in the infrared. The performance of previously reported ENZ material-based optical switches, however, has been greatly hampered by the low quality- (Q-) factor of the ENZ cavity, resulting in a large required optical pump fluence or applied voltage, a large insertion loss, or a small modulation depth. Here, we propose a solution by integrating the ENZ material into a Bragg microcavity, such that the Q-factor of the coupled cavity can be dramatically enhanced. Using high-mobility Dysprosium-doped cadmium oxide (CdO) as the prototype ENZ material, we numerically show an infrared all-optical switch with its reflectance modulated from near-zero to 94% under a pump fluence of only 7 μJ cm-2, about a 59-time-reduction compared with a state-of-the-art Berreman-type cavity. Moreover, the high-Q coupled cavity can also be adopted to realize a reflective electro-optical switch. Its reflectance can be switched from near-zero to 89%, with a bias electric field well below the breakdown field of conventional gate dielectrics. The switching operation can further be extended to the transmission mode with a slightly modified cavity geometry, with its absolute transmittance modulated by 40%.
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15
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Ratchford D, Winta CJ, Chatzakis I, Ellis CT, Passler NC, Winterstein J, Dev P, Razdolski I, Matson JR, Nolen JR, Tischler JG, Vurgaftman I, Katz MB, Nepal N, Hardy MT, Hachtel JA, Idrobo JC, Reinecke TL, Giles AJ, Katzer DS, Bassim ND, Stroud RM, Wolf M, Paarmann A, Caldwell JD. Controlling the Infrared Dielectric Function through Atomic-Scale Heterostructures. ACS NANO 2019; 13:6730-6741. [PMID: 31184132 PMCID: PMC6750877 DOI: 10.1021/acsnano.9b01275] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/04/2019] [Indexed: 05/25/2023]
Abstract
Surface phonon polaritons (SPhPs), the surface-bound electromagnetic modes of a polar material resulting from the coupling of light with optic phonons, offer immense technological opportunities for nanophotonics in the infrared (IR) spectral region. However, once a particular material is chosen, the SPhP characteristics are fixed by the spectral positions of the optic phonon frequencies. Here, we provide a demonstration of how the frequency of these optic phonons can be altered by employing atomic-scale superlattices (SLs) of polar semiconductors using AlN/GaN SLs as an example. Using second harmonic generation (SHG) spectroscopy, we show that the optic phonon frequencies of the SLs exhibit a strong dependence on the layer thicknesses of the constituent materials. Furthermore, new vibrational modes emerge that are confined to the layers, while others are centered at the AlN/GaN interfaces. As the IR dielectric function is governed by the optic phonon behavior in polar materials, controlling the optic phonons provides a means to induce and potentially design a dielectric function distinct from the constituent materials and from the effective-medium approximation of the SL. We show that atomic-scale AlN/GaN SLs instead have multiple Reststrahlen bands featuring spectral regions that exhibit either normal or extreme hyperbolic dispersion with both positive and negative permittivities dispersing rapidly with frequency. Apart from the ability to engineer the SPhP properties, SL structures may also lead to multifunctional devices that combine the mechanical, electrical, thermal, or optoelectronic functionality of the constituent layers. We propose that this effort is another step toward realizing user-defined, actively tunable IR optics and sources.
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Affiliation(s)
| | - Christopher J. Winta
- Physikalische
Chemie, Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin, Germany
| | - Ioannis Chatzakis
- ASEE
Postdoctoral Associate, U.S. Naval Research
Laboratory, Washington, D.C. 20375, United
States
| | - Chase T. Ellis
- U.S.
Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Nikolai C. Passler
- Physikalische
Chemie, Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin, Germany
| | | | - Pratibha Dev
- Department
of Physics and Astronomy, Howard University, Washington, D.C. 20059, United States
| | - Ilya Razdolski
- Physikalische
Chemie, Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin, Germany
- FELIX
Laboratory, Faculty of Science, Radboud
University, 6500 GL Nijmegen, The Netherlands
| | - Joseph R. Matson
- Department
of Mechanical Engineering, Vanderbilt University, 2400 Highland Avenue, Nashville, Tennessee 37212, United States
| | - Joshua R. Nolen
- Department
of Mechanical Engineering, Vanderbilt University, 2400 Highland Avenue, Nashville, Tennessee 37212, United States
| | | | - Igor Vurgaftman
- U.S.
Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Michael B. Katz
- NRC
Postdoctoral Associate, U.S. Naval Research
Laboratory, Washington, D.C. 20375, United
States
| | - Neeraj Nepal
- U.S.
Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Matthew T. Hardy
- U.S.
Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Jordan A. Hachtel
- Center
for Nanophase Materials Science, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Juan-Carlos Idrobo
- Center
for Nanophase Materials Science, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37831, United States
| | | | | | - D. Scott Katzer
- U.S.
Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Nabil D. Bassim
- U.S.
Naval Research Laboratory, Washington, D.C. 20375, United States
- Department
of Materials Science and Engineering, McMaster
University, Hamilton, Ontario JHE 357, Canada
| | - Rhonda M. Stroud
- U.S.
Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Martin Wolf
- Physikalische
Chemie, Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin, Germany
| | - Alexander Paarmann
- Physikalische
Chemie, Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin, Germany
| | - Joshua D. Caldwell
- U.S.
Naval Research Laboratory, Washington, D.C. 20375, United States
- Department
of Mechanical Engineering, Vanderbilt University, 2400 Highland Avenue, Nashville, Tennessee 37212, United States
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