Yao-Wei Huang, N. Rubin, A. Ambrosio, R. Devlin, C. Qiu, F. Capasso
Optical elements that couple the spin/orbital angular momentum (SAM/OAM) of light have found a range of applications in classical and quantum optics. The J-plate, which refers to the variable denoting the photon’s total angular momentum (TAM), is a metasurface device that allows converting arbitrary, orthogonal input SAM states into two unique OAM states. Using independent phase control of any orthogonal basis of polarization states, the J-plate permits the conversion of arbitrary polarizations into states with arbitrary OAM. Here, we present a further development: Cascaded J-plates provide for versatile combinations of OAM states on any orthogonal basis of spin states. J-plates operating on different polarization bases and imparting independent values of OAM are designed and experimentally demonstrated to generate multiple OAM channels with different polarization states. The generated OAM states are determined by the superposition of the OAM states of the individual J-plates while the generated SAM states are determined by the polarization basis of the last J-plate. Theoretically, there are maximum of 2^n channels of OAM and n×2^n channels of TAM that can be generated by n such cascaded J-plates. It is also demonstrated that cascaded J-plates may produce complex structured light. Cascading J-plates provides a new way to control the TAM of a laser beam. These results may find application in quantum and classical communication.
{"title":"Versatile total angular momentum generation using cascaded J-plates (Conference Presentation)","authors":"Yao-Wei Huang, N. Rubin, A. Ambrosio, R. Devlin, C. Qiu, F. Capasso","doi":"10.1117/12.2322870","DOIUrl":"https://doi.org/10.1117/12.2322870","url":null,"abstract":"Optical elements that couple the spin/orbital angular momentum (SAM/OAM) of light have found a range of applications in classical and quantum optics. The J-plate, which refers to the variable denoting the photon’s total angular momentum (TAM), is a metasurface device that allows converting arbitrary, orthogonal input SAM states into two unique OAM states. Using independent phase control of any orthogonal basis of polarization states, the J-plate permits the conversion of arbitrary polarizations into states with arbitrary OAM. Here, we present a further development: Cascaded J-plates provide for versatile combinations of OAM states on any orthogonal basis of spin states. J-plates operating on different polarization bases and imparting independent values of OAM are designed and experimentally demonstrated to generate multiple OAM channels with different polarization states. The generated OAM states are determined by the superposition of the OAM states of the individual J-plates while the generated SAM states are determined by the polarization basis of the last J-plate. Theoretically, there are maximum of 2^n channels of OAM and n×2^n channels of TAM that can be generated by n such cascaded J-plates. It is also demonstrated that cascaded J-plates may produce complex structured light. Cascading J-plates provides a new way to control the TAM of a laser beam. These results may find application in quantum and classical communication.","PeriodicalId":169708,"journal":{"name":"Metamaterials, Metadevices, and Metasystems 2018","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127576263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Reddy, U. Guler, K. Chaudhuri, Z. Kudyshev, A. Kildishev, V. Shalaev, A. Boltasseva
Understanding the temperature evolution of optical properties in thin metals is critical for rational design of practical metal based nanophotonic components operating at high temperatures in a variety of research areas, including plasmonics and near-field radiative heat transfer. In this talk, we will present our recent experimental findings on the temperature induced deviations in the optical responses of single- and poly-crystalline metal films – gold, silver and titanium nitride thin films - at elevated temperatures upto 900 0C, in the wavelength range from 370 to 2000 nm. Our findings show that while the real part of the dielectric function changes marginally with temperature, the imaginary part varies drastically. Furthermore, the temperature dependencies were found to be strongly dependent on the film thickness and microstructure/crystallinity. We attribute the observed changes in the optical properties to predominantly three physical processes: 1) increasing electron-phonon interactions, 2) reducing free electron densities and, 3) changes in the electron effective mass. Using extensive numerical simulations we demonstrate the importance of incorporating the temperature induced deviations into numerical models for accurate multiphysics modeling of practical high temperature plasmonic components. We also provide experiment-fitted models to describe the temperature-dependent metal dielectric functions as a sum of Drude and critical point/Lorentz oscillators. These causal analytical models could enable accurate multiphysics modeling of nanophotonic and plasmonic components operating at high temperatures in both frequency and time domains.
{"title":"Temperature evolution of optical properties in plasmonic metals (Conference Presentation)","authors":"H. Reddy, U. Guler, K. Chaudhuri, Z. Kudyshev, A. Kildishev, V. Shalaev, A. Boltasseva","doi":"10.1117/12.2320142","DOIUrl":"https://doi.org/10.1117/12.2320142","url":null,"abstract":"Understanding the temperature evolution of optical properties in thin metals is critical for rational design of practical metal based nanophotonic components operating at high temperatures in a variety of research areas, including plasmonics and near-field radiative heat transfer. In this talk, we will present our recent experimental findings on the temperature induced deviations in the optical responses of single- and poly-crystalline metal films – gold, silver and titanium nitride thin films - at elevated temperatures upto 900 0C, in the wavelength range from 370 to 2000 nm. Our findings show that while the real part of the dielectric function changes marginally with temperature, the imaginary part varies drastically. Furthermore, the temperature dependencies were found to be strongly dependent on the film thickness and microstructure/crystallinity. We attribute the observed changes in the optical properties to predominantly three physical processes: 1) increasing electron-phonon interactions, 2) reducing free electron densities and, 3) changes in the electron effective mass. Using extensive numerical simulations we demonstrate the importance of incorporating the temperature induced deviations into numerical models for accurate multiphysics modeling of practical high temperature plasmonic components. We also provide experiment-fitted models to describe the temperature-dependent metal dielectric functions as a sum of Drude and critical point/Lorentz oscillators. These causal analytical models could enable accurate multiphysics modeling of nanophotonic and plasmonic components operating at high temperatures in both frequency and time domains.","PeriodicalId":169708,"journal":{"name":"Metamaterials, Metadevices, and Metasystems 2018","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132210733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Shalaginov, Yifei Zhang, S. An, J. Chou, Qingyang Du, A. Yadav, M. Kang, Cesar Blanco, P. Su, M. Driggers, A. Kirk, E. Baleine, A. Agarwal, C. Rivero‐Baleine, V. Liberman, K. Richardson, Hualiang Zhang, Juejun Hu, T. Gu
The dramatic optical property change of optical phase change materials (O-PCMs) between their amorphous and crystalline states potentially allows the realization of reconfigurable photonic devices with enhanced optical functionalities and low power consumption, such as reconfigurable optical components, optical switches and routers, and photonic memories. Conventional O-PCMs exhibit considerable optical losses, limiting their optical performance as well as application space. In this talk, we present the development of a new group of O-PCMs and their implementations in novel meta-optic devices. Ge-Sb-Se-Te (GSST), obtained by partially substituting Te with Se in traditional GST alloys, feature unprecedented broadband optical transparency covering the telecommunication bands to the LWIR. A drastic refractive index change between the amorphous and crystalline states of GSST is realized and the transition is non-volatile and reversible. Optical metasurfaces consist of optically-thin, subwavelength meta-atom arrays which allow arbitrary manipulation of the wavefront of light. Capitalizing on the dramatically-enhanced optical performance of GSST, transparent and ultra-thin reconfigurable meta-optics in mid-infrared are demonstrated. In one example, GSST-based all-dielectric nano-antennae are used as the fundamental building blocks for meta-optic components. Tunable and switchable metasurface devices are developed, taking advantage of the materials phase changing properties.
{"title":"Ultra-thin, reconfigurable meta-optics using optical phase change materials (Conference Presentation)","authors":"M. Shalaginov, Yifei Zhang, S. An, J. Chou, Qingyang Du, A. Yadav, M. Kang, Cesar Blanco, P. Su, M. Driggers, A. Kirk, E. Baleine, A. Agarwal, C. Rivero‐Baleine, V. Liberman, K. Richardson, Hualiang Zhang, Juejun Hu, T. Gu","doi":"10.1117/12.2323580","DOIUrl":"https://doi.org/10.1117/12.2323580","url":null,"abstract":"The dramatic optical property change of optical phase change materials (O-PCMs) between their amorphous and crystalline states potentially allows the realization of reconfigurable photonic devices with enhanced optical functionalities and low power consumption, such as reconfigurable optical components, optical switches and routers, and photonic memories. Conventional O-PCMs exhibit considerable optical losses, limiting their optical performance as well as application space. In this talk, we present the development of a new group of O-PCMs and their implementations in novel meta-optic devices. Ge-Sb-Se-Te (GSST), obtained by partially substituting Te with Se in traditional GST alloys, feature unprecedented broadband optical transparency covering the telecommunication bands to the LWIR. A drastic refractive index change between the amorphous and crystalline states of GSST is realized and the transition is non-volatile and reversible. \u0000\u0000Optical metasurfaces consist of optically-thin, subwavelength meta-atom arrays which allow arbitrary manipulation of the wavefront of light. Capitalizing on the dramatically-enhanced optical performance of GSST, transparent and ultra-thin reconfigurable meta-optics in mid-infrared are demonstrated. In one example, GSST-based all-dielectric nano-antennae are used as the fundamental building blocks for meta-optic components. Tunable and switchable metasurface devices are developed, taking advantage of the materials phase changing properties.","PeriodicalId":169708,"journal":{"name":"Metamaterials, Metadevices, and Metasystems 2018","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121097555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Topological insulators are materials that behave as insulators in their interior but support boundary conducting states due the non-trivial topological order. These edge states are robust to defects and imperfections, allowing lossless energy transport along the surface. Topological insulators were first discovered in field of electronics, but recently photonic analogues of these systems were realized. Most of experimentally demonstrated photonic topological insulators to date are bulky, incompatible with current semiconductor fabrication process or operate in microwave frequency range. In this work, we show silicon photonic-crystal-based Valley-Hall topological insulator operating at telecommunication wavelengths. Light propagation along the trapezoidally-shaped path with four 120 degrees turns is demonstrated and compared with propagation along the straight line. Nearly the same transmittance values for both cases confirm robust light transport in such Valley-Hall topological photonic crystal. In the second part of this talk, we discuss the possibility of dynamic tuning of the proposed topological insulator by modulation of the refractive index of silicon. The modulation is facilitated by shining focused ultraviolet pulsed light onto silicon photonic crystal slab. Ultraviolet light illumination causes formation of electron-hole pairs, excitation of free-carriers and results into decrease of refractive index with estimated modulation on the order of 0.1. Due to the index change, spectral position of the bandgap and the edge states shift allowing their dynamic control. Proposed concept can find applications in communication field for fast all-optical switching and control over light propagation.
{"title":"Experimental demonstration of silicon-based topological photonic crystal slab at near infrared frequencies and its dynamic tunability (Conference Presentation)","authors":"M. Shalaev, W. Walasik, N. Litchinitser","doi":"10.1117/12.2321252","DOIUrl":"https://doi.org/10.1117/12.2321252","url":null,"abstract":"Topological insulators are materials that behave as insulators in their interior but support boundary conducting states due the non-trivial topological order. These edge states are robust to defects and imperfections, allowing lossless energy transport along the surface. Topological insulators were first discovered in field of electronics, but recently photonic analogues of these systems were realized. Most of experimentally demonstrated photonic topological insulators to date are bulky, incompatible with current semiconductor fabrication process or operate in microwave frequency range. In this work, we show silicon photonic-crystal-based Valley-Hall topological insulator operating at telecommunication wavelengths. Light propagation along the trapezoidally-shaped path with four 120 degrees turns is demonstrated and compared with propagation along the straight line. Nearly the same transmittance values for both cases confirm robust light transport in such Valley-Hall topological photonic crystal. In the second part of this talk, we discuss the possibility of dynamic tuning of the proposed topological insulator by modulation of the refractive index of silicon. The modulation is facilitated by shining focused ultraviolet pulsed light onto silicon photonic crystal slab. Ultraviolet light illumination causes formation of electron-hole pairs, excitation of free-carriers and results into decrease of refractive index with estimated modulation on the order of 0.1. Due to the index change, spectral position of the bandgap and the edge states shift allowing their dynamic control. Proposed concept can find applications in communication field for fast all-optical switching and control over light propagation.","PeriodicalId":169708,"journal":{"name":"Metamaterials, Metadevices, and Metasystems 2018","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125024005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"From inverse design to implementation of practical and robust photonics (Conference Presentation)","authors":"J. Vučković","doi":"10.1117/12.2319237","DOIUrl":"https://doi.org/10.1117/12.2319237","url":null,"abstract":"","PeriodicalId":169708,"journal":{"name":"Metamaterials, Metadevices, and Metasystems 2018","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122025588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Metamaterials are artificial structures, having extraordinary abilities to manipulate electromagnetic waves far beyond the limits of natural materials. Due to the technology of fabrication, planer metamaterials are greatly restricted by pure magnetic resonant modes induced by in-plane EM waves. In this work, we numerically demonstrate vertical double-split ring resonators by finite-element method software (CST). Our samples were fabricated by metal stress-driven self-folding method, which is so called 4D printing. In the beginning, we define our patterns in two-dimensional with by electron beam lithography and deposit Ni/Au bilayer metal on silicon substrate. After etching out underlying substrate by ICP-RIE, released stress in metal will deform our 2D metal patterns into 3D metamaterials. Comparing with single-split ring resonators, DSRRs are considered with more freedom to tailor resonance frequency by changing the length of arms and the distance between them. Here we investigated the effects of symmetry breaking and resonance mode hybridization at mid-infrared wavelength using coupled DSRRs. The proposed 3D metamaterials indicate some potential applications like modulators and filters in compact optical metadevices.
{"title":"Study on symmetry breaking in vertical double split ring resonators (Conference Presentation)","authors":"Hao-Yuan Tsai, Che-Chin Chen, T. Yen","doi":"10.1117/12.2320257","DOIUrl":"https://doi.org/10.1117/12.2320257","url":null,"abstract":"Metamaterials are artificial structures, having extraordinary abilities to manipulate electromagnetic waves far beyond the limits of natural materials. Due to the technology of fabrication, planer metamaterials are greatly restricted by pure magnetic resonant modes induced by in-plane EM waves.\u0000In this work, we numerically demonstrate vertical double-split ring resonators by finite-element method software (CST). Our samples were fabricated by metal stress-driven self-folding method, which is so called 4D printing. In the beginning, we define our patterns in two-dimensional with by electron beam lithography and deposit Ni/Au bilayer metal on silicon substrate. After etching out underlying substrate by ICP-RIE, released stress in metal will deform our 2D metal patterns into 3D metamaterials. \u0000Comparing with single-split ring resonators, DSRRs are considered with more freedom to tailor resonance frequency by changing the length of arms and the distance between them. Here we investigated the effects of symmetry breaking and resonance mode hybridization at mid-infrared wavelength using coupled DSRRs. The proposed 3D metamaterials indicate some potential applications like modulators and filters in compact optical metadevices.","PeriodicalId":169708,"journal":{"name":"Metamaterials, Metadevices, and Metasystems 2018","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129757066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nonlinear plasmonic metasurfaces: focusing on the Lorentz contribution (Conference Presentation)","authors":"E. Rahimi, Haitian Xu, B. Choi, R. Gordon","doi":"10.1117/12.2319413","DOIUrl":"https://doi.org/10.1117/12.2319413","url":null,"abstract":"","PeriodicalId":169708,"journal":{"name":"Metamaterials, Metadevices, and Metasystems 2018","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132164516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Nouman, Ji Hyun Hwang, Kye-Jeong Lee, C. M. Leite, D. Ko, Jae‐Hyung Jang
{"title":"Designing over and under coupled resonant metamaterial cavities to control reflection mode optical phase characteristics (Conference Presentation)","authors":"M. Nouman, Ji Hyun Hwang, Kye-Jeong Lee, C. M. Leite, D. Ko, Jae‐Hyung Jang","doi":"10.1117/12.2323173","DOIUrl":"https://doi.org/10.1117/12.2323173","url":null,"abstract":"","PeriodicalId":169708,"journal":{"name":"Metamaterials, Metadevices, and Metasystems 2018","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130666610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Topological photonics enable us to design novel devices that exploit counter-intuitive propagation of electromagnetic waves. The key ingredient of topological photonics is a photonic topological insulator (PTI): a periodic structure that, in its bulk form, exhibits a propagation bandgap for a range of frequencies, yet supports localized edge states when interfaced with a different photonic structure exhibiting a bandgap for the same frequency range. Several types of PTIs emulating their respective condensed matter counterparts have already been proposed and experimentally demonstrated. One of the simplest PTIs exploits the valley degree of freedom in photonic crystals with a C_3 spatial symmetry. I will describe two examples of such structures: one designed and experimentally demonstrated at microwave frequencies and another designed for the mid-IR spectral range. We show that the microwave PTI structure, which is based on a metallic waveguide with an embedded array of specially designed metal rods, exhibits the previously unknown phenomenon of valley-protected “perfect” refraction: when interfaced with another waveguide, the edge states refract from the PTI metamaterial into the waveguide without any reflection. For the nanoscale topological metamaterial, we utilize graphene surface plasmons (GSPs) that propagate through a sheet of graphene with nano-patterned landscape of chemical potential. The chemical potential landscaping is achieved using an electrically biased metagate placed in close proximity of the graphene sheet. The advantage of this scheme is that the topological properties of the GSPs can be rapidly turned on and off, thus heralding the new era of active topological photonics on a nanoscale
{"title":"Valley degree of freedom in topological metamaterials: from microwaves in meta-waveguides to nanoscale surface graphene plasmons (Conference Presentation)","authors":"G. Shvets","doi":"10.1117/12.2324266","DOIUrl":"https://doi.org/10.1117/12.2324266","url":null,"abstract":"Topological photonics enable us to design novel devices that exploit counter-intuitive propagation of electromagnetic waves. The key ingredient of topological photonics is a photonic topological insulator (PTI): a periodic structure that, in its bulk form, exhibits a propagation bandgap for a range of frequencies, yet supports localized edge states when interfaced with a different photonic structure exhibiting a bandgap for the same frequency range. Several types of PTIs emulating their respective condensed matter counterparts have already been proposed and experimentally demonstrated. One of the simplest PTIs exploits the valley degree of freedom in photonic crystals with a C_3 spatial symmetry. I will describe two examples of such structures: one designed and experimentally demonstrated at microwave frequencies and another designed for the mid-IR spectral range. We show that the microwave PTI structure, which is based on a metallic waveguide with an embedded array of specially designed metal rods, exhibits the previously unknown phenomenon of valley-protected “perfect” refraction: when interfaced with another waveguide, the edge states refract from the PTI metamaterial into the waveguide without any reflection. For the nanoscale topological metamaterial, we utilize graphene surface plasmons (GSPs) that propagate through a sheet of graphene with nano-patterned landscape of chemical potential. The chemical potential landscaping is achieved using an electrically biased metagate placed in close proximity of the graphene sheet. The advantage of this scheme is that the topological properties of the GSPs can be rapidly turned on and off, thus heralding the new era of active topological photonics on a nanoscale","PeriodicalId":169708,"journal":{"name":"Metamaterials, Metadevices, and Metasystems 2018","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128809187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Wu, Kyusang Choi, D. Kim, E. Choi, Eunsun Kim, Y. Lee, Virginie Placide, D. Yao, F. Mathevet, H. Kim, J. Ribierre, E. Zaborova, F. Fages, A. D'Aléo
Epsilon-near-zero (ENZ) material possesses the dielectric permittivity near-zero in a range of optical spectrum. Real part of Drude-type dielectric permittivity goes through zero at the plasma frequency of noble metals, doped semiconductor, and conducting oxide. Another example is hyperbolic metamaterial, where transverse negative and transverse positive hyperbolic dispersions are distinguished at ENZ spectral position. In organic molecular aggregates a van der Waals coupling between ground and excited states of neighboring molecular excitons leads to resonance Davydov splitting, resulting in a coherent super dipole moment. A collection of Lorentzian oscillators in a narrow spectral range is associated with a negative real part dielectric permittivity from Kramers-Kronig dispersion relation, permitting the existence of ENZ spectral range. We study a series of optical films of donor-acceptor-donor organic pi-conjugated molecules to relate the strength of donor group with ENZ property. In order to characterize ENZ spectral response, spectroscopic ellipsometry (SE), attenuated total internal reflection (ATR) spectra, GIWAXS and NEXAFS measurements as well as linear optical spectra of reflection and absorption are employed. Also to relate linear optical spectra with ATR spectra, FDTD simulation is carried out by use of dielectric permittivity spectra obtained from SE measurement. Preliminary data show that both strength of donor group of individual organic molecules and the orientation of molecular planes as well as degree of aggregates of molecular aggregates in film are associated with ENZ response. Advantages of organic ENZ materials are found to be the simple sample preparation by spin-coating or thermal evaporation and the tunability of ENZ spectral range covering visible and near IR spectrum.
{"title":"Characteristics of organic epsilon-near-zero materials (Conference Presentation)","authors":"J. Wu, Kyusang Choi, D. Kim, E. Choi, Eunsun Kim, Y. Lee, Virginie Placide, D. Yao, F. Mathevet, H. Kim, J. Ribierre, E. Zaborova, F. Fages, A. D'Aléo","doi":"10.1117/12.2320848","DOIUrl":"https://doi.org/10.1117/12.2320848","url":null,"abstract":"Epsilon-near-zero (ENZ) material possesses the dielectric permittivity near-zero in a range of optical spectrum. Real part of Drude-type dielectric permittivity goes through zero at the plasma frequency of noble metals, doped semiconductor, and conducting oxide. Another example is hyperbolic metamaterial, where transverse negative and transverse positive hyperbolic dispersions are distinguished at ENZ spectral position. In organic molecular aggregates a van der Waals coupling between ground and excited states of neighboring molecular excitons leads to resonance Davydov splitting, resulting in a coherent super dipole moment. A collection of Lorentzian oscillators in a narrow spectral range is associated with a negative real part dielectric permittivity from Kramers-Kronig dispersion relation, permitting the existence of ENZ spectral range. We study a series of optical films of donor-acceptor-donor organic pi-conjugated molecules to relate the strength of donor group with ENZ property. In order to characterize ENZ spectral response, spectroscopic ellipsometry (SE), attenuated total internal reflection (ATR) spectra, GIWAXS and NEXAFS measurements as well as linear optical spectra of reflection and absorption are employed. Also to relate linear optical spectra with ATR spectra, FDTD simulation is carried out by use of dielectric permittivity spectra obtained from SE measurement. Preliminary data show that both strength of donor group of individual organic molecules and the orientation of molecular planes as well as degree of aggregates of molecular aggregates in film are associated with ENZ response. Advantages of organic ENZ materials are found to be the simple sample preparation by spin-coating or thermal evaporation and the tunability of ENZ spectral range covering visible and near IR spectrum.","PeriodicalId":169708,"journal":{"name":"Metamaterials, Metadevices, and Metasystems 2018","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126038267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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