Publications
799 results found
Pusch A, Oh S, Wuestner S, et al., 2015, A highly efficient CMOS nanoplasmonic crystal enhanced slow-wave thermal emitter improves infrared gas-sensing devices, Scientific Reports, Vol: 5, ISSN: 2045-2322
The application of plasmonics to thermal emitters is generally assisted by absorptive losses in the metal because Kirchhoff’s law prescribes that only good absorbers make good thermal emitters. Based on a designed plasmonic crystal and exploiting a slow-wave lattice resonance and spontaneous thermal plasmon emission, we engineer a tungsten-based thermal emitter, fabricated in an industrial CMOS process, and demonstrate its markedly improved practical use in a prototype non-dispersive infrared (NDIR) gas-sensing device. We show that the emission intensity of the thermal emitter at the CO2 absorption wavelength is enhanced almost 4-fold compared to a standard non-plasmonic emitter, which enables a proportionate increase in the signal-to-noise ratio of the CO2 gas sensor.
Schaich WL, 2015, Comment on "Surface Plasmons and Nonlocality: A Simple Model"., Phys Rev Lett, Vol: 115
A Comment on the Letter by Y. Luo, A. I. Fernandez-Dominguez, A. Wiener, S. A. Maier, and J. B. Pendry, Phys. Rev. Lett. 111, 093901 (2013).. The authors of the Letter offer a Reply.
Luo Y, Fernandez-Dominguez AI, Wiener A, et al., 2015, Reply to "Comment on “Surface Plasmons and Nonlocality: A Simple Model”, Physical Review Letters, Vol: 115, ISSN: 1079-7114
Schaich WL, Luo Y, Fernandez-Dominguez AI, et al., 2015, Comment on "Surface Plasmons and Nonlocality: A Simple Model", PHYSICAL REVIEW LETTERS, Vol: 115, ISSN: 0031-9007
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- Citations: 4
Turek VA, Francescato Y, Cadinu P, et al., 2015, Self-Assembled Spherical Supercluster Metamaterials from Nanoscale Building Blocks, ACS Photonics, Vol: 3, Pages: 35-42, ISSN: 2330-4022
We report on a simple, universal and large scale self-assembly method for generation of spherical superclusters from nanoscopic building blocks. The fundamentals of this approach relies on the ultra-high pre-concentration of nanoparticles (NP) followed by either using emulsification strategies or alternatively multiphase microfluidic microdroplets. In both cases drying of the NP droplets yield highly spherical self-assembled superclusters with unique optical properties. We demonstrate that the behaviour of these spheres can be controlled by surface functionalization before and after the self-assembly process. These structures show unique plasmonic collective response both on the surface and within the supercluster in the visible and infrared regions. Furthermore, we demonstrate that these strong, tunable optical modes can be used towards ultra-sensitive, reproducible, surface-enhanced spectroscopies.
Mehmood MQ, Liu H, Huang K, et al., 2015, Broadband spin-controlled focusing via logarithmic-spiral nanoslits of varying width, Laser & Photonics Reviews, Vol: 9, Pages: 674-681, ISSN: 1863-8899
This work presents analytical, numerical and experimental demonstrations of light diffracted through a logarithmic spiral (LS) nanoslit, which forms a type of switchable and focus-tunable structure. Owing to a strong dependence on the incident photon spin, the proposed LS-nanoslit converges incoming light of opposite handedness (to that of the LS-nanoslit) into a confined subwavelength spot, while it shapes light with similar chirality into a donut-like intensity profile. Benefitting from the varying width of the LS-nanoslit, different incident wavelengths interfere constructively at different positions, i.e., the focal length shifts from 7.5 μm (at λ = 632.8 nm) to 10 μm (at λ = 488 nm), which opens up new opportunities for tuning and spatially separating broadband light at the micrometer scale.
Kraft M, Luo Y, Maier SA, et al., 2015, Designing plasmonic gratings with transformation optics, Physical Review X, Vol: 5, ISSN: 2160-3308
Plasmonic gratings that support both localized and propagating plasmons have wide applications in solar cells and optical biosensing. In this paper, we report on a most unusual grating designed to capture light efficiently into surface plasmons and concentrate their energy at hot spots where the field is resonantly enhanced. The dispersion of the surface plasmons shows degeneracy points at k=0, where, despite a strongly modulated grating, hidden symmetries forbid hybridization of plasmons traveling in opposite directions.
Lei DY, Appavoo K, Ligmajer F, et al., 2015, Optically-Triggered Nanoscale Memory Effect in a Hybrid Plasmonic-Phase Changing Nanostructure, ACS PHOTONICS, Vol: 2, Pages: 1306-1313, ISSN: 2330-4022
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- Citations: 101
Caldarola M, Albella P, Cortés E, et al., 2015, Non-plasmonic nanoantennas for surface enhanced spectroscopies with ultra-low heat conversion, Nature Communications, Vol: 6, ISSN: 2041-1723
Nanoplasmonics has recently revolutionized our ability to control light on the nanoscale. Using metallic nanostructures with tailored shapes, it is possible to efficiently focus light into nanoscale field 'hot spots'. High field enhancement factors have been achieved in such optical nanoantennas, enabling transformative science in the areas of single molecule interactions, highly enhanced nonlinearities and nanoscale waveguiding. Unfortunately, these large enhancements come at the price of high optical losses due to absorption in the metal, severely limiting real-world applications. Via the realization of a novel nanophotonic platform based on dielectric nanostructures to form efficient nanoantennas with ultra-low light-into-heat conversion, here we demonstrate an approach that overcomes these limitations. We show that dimer-like silicon-based single nanoantennas produce both high surface enhanced fluorescence and surface enhanced Raman scattering, while at the same time generating a negligible temperature increase in their hot spots and surrounding environments.
Aouani H, Navarro-Cía M, Rahmani M, et al., 2015, Corrections to Unveiling the Origin of Third Harmonic Generation in Hybrid ITO-Plasmonic Crystals [Adv. Optical Mater., 3, 8, (2015) 1059-1065], DOI: 10.1002/adom.201500112, Advanced Optical Materials, Vol: 3, Pages: 986-986
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- Citations: 1
Daskalakis KS, Maier SA, Kena-Cohen S, 2015, Spatial Coherence and Stability in a Disordered Organic Polariton Condensate, PHYSICAL REVIEW LETTERS, Vol: 115, ISSN: 0031-9007
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- Citations: 47
Tufarelli T, McEnery KR, Maier SA, et al., 2015, Signatures of the A2 term in ultrastrongly coupled oscillators, Physical Review A, Vol: 91, ISSN: 1094-1622
We study a bosonic matter excitation coupled to a single-mode cavity field via electric dipole. Counter-rotating and A2 terms are included in the interaction model, A being the vector potential of the cavity field. In the ultrastrong coupling regime the vacuum of the bare modes is no longer the ground state of the Hamiltonian and contains a nonzero population of polaritons, the true normal modes of the system. If the parameters of the model satisfy the Thomas-Reiche-Kuhn sum rule, we find that the two polaritons are always equally populated. We show how this prediction could be tested in a quenching experiment, by rapidly switching on the coupling and analyzing the radiation emitted by the cavity. A refinement of the model based on a microscopic minimal coupling Hamiltonian is also provided, and its consequences on our results are characterized analytically.
Chen Y, Li X, Luo X, et al., 2015, Tunable near-infrared plasmonic perfect absorber based on phase-change materials, PHOTONICS RESEARCH, Vol: 3, Pages: 54-57
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- Citations: 109
Krapek V, Koh AL, Brinek L, et al., 2015, Spatially resolved electron energy loss spectroscopy of crescent-shaped plasmonic antennas, Optics Express, Vol: 23, Pages: 11855-11867, ISSN: 1094-4087
We present a study of the optical properties of gold crescentshapedantennas by means of electron energy loss spectroscopy. Thesestructures exhibit particularly large field enhancement near their sharpfeatures, support two non-degenerate dipolar (i.e., optically active) localisedsurface plasmon resonances, and are widely tunable by a choice of theirshape and dimensions. Depending on the volume and shape, we resolved upto four plasmon resonances in metallic structures under study in the energyrange of 0.8 – 2.4 eV: two dipolar and quadrupolar mode and a multimodalassembly. The boundary-element-method calculations reproduced theobserved spectra and helped to identify the character of the resonances.The two lowest modes are of particular importance owing to their dipolarnature. Remarkably, they are both concentrated near the tips of the crescent,spectrally well resolved and their energies can be tuned between 0.8 – 1.5eV and 1.2 – 2.0 eV, respectively. As the lower spectral range coversthe telecommunication wavelengths 1.30 and 1.55 μm, we envisage thepossible use of such nanostructures in infrared communication technology
Gilbertson AM, Francescato Y, Roschuk T, et al., 2015, Plasmon-Induced Optical Anisotropy in Hybrid Graphene-Metal Nanoparticle Systems, NANO LETTERS, Vol: 15, Pages: 3458-3464, ISSN: 1530-6984
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- Citations: 43
Hadjicosti K, Sydoruk O, Maier SA, et al., 2015, Surface polaritons in magnetic metamaterials from perspective of effective-medium and circuit models, Journal of Applied Physics, Vol: 117, ISSN: 1089-7550
Surface waves are responsible for many phenomena occurring in metamaterials and have been studiedextensively. At the same time, the effects of inter-element coupling on surface electromagnetic waves(polaritons) remain poorly understood. Using two models, one relying on the effective-mediumapproximation and the other on equivalent circuits, we studied theoretically surface polaritonspropagating along an interface between air and a magnetic metamaterial. The metamaterial comprisedsplit rings that could be uncoupled or coupled to each other in the longitudinal or transverse directions(along or perpendicular to the propagation direction). A metamaterial without inter-element couplingsupported a single polariton. When a moderate longitudinal coupling was included, it changed thewave dispersion only quantitatively, and the results of the effective-medium and the circuit modelswere shown to agree at low wavenumbers. However, the presence of a transverse coupling changedthe polariton dispersion dramatically. The effective-medium model yielded two branches of polaritondispersion at low values of the transverse coupling. As the coupling increased, both polaritonsdisappeared. The validity of the effective-medium model was further tested by employing the circuitmodel. In this model, surface polaritons could exist in the presence of a transverse coupling only if theboundary layer of the metamaterial included additional impedances, which could become non-Foster.The results reveal that the inter-element coupling is a major mechanism affecting the properties of thepolaritons. They also highlight the limitations of using bulk effective-medium parameters for interfaceproblems in metamaterials.
Okell WA, Witting T, Fabris D, et al., 2015, Temporal broadening of attosecond photoelectron wavepackets from solid surfaces, Optica, Vol: 2, Pages: 383-387, ISSN: 2334-2536
Liao Z, Luo Y, Fernández-Domínguez AI, et al., 2015, High-order localized spoof surface plasmon resonances and experimental verifications., Scientific Reports, Vol: 5, ISSN: 2045-2322
We theoretically demonstrated and experimentally verified high-order radial spoof localized surface plasmon resonances supported by textured metal particles. Through an effective medium theory and exact numerical simulations, we show the emergence of these geometrically-originated electromagnetic modes at microwave frequencies. The occurrence of high-order radial spoof plasmon resonances is experimentally verified in ultrathin disks. Their spectral and near-field properties are characterized experimentally, showing an excellent agreement with theoretical predictions. Our findings shed light into the nature of spoof localized surface plasmons, and open the way to the design of broadband plasmonic devices able to operate at very different frequency regimes.
Caldwell JD, Lindsay L, Giannini V, et al., 2015, Low-loss, infrared and terahertz nanophotonics using surface phonon polaritons, Nanophotonics, Vol: 4, Pages: 44-68, ISSN: 2192-8614
The excitation of surface-phonon-polariton (SPhP) modes in polar dielectric crystals and the associated new developments in the field of SPhPs are reviewed. The emphasis of this work is on providing an understanding of the general phenomenon, including the origin of the Reststrahlen band, the role that optical phonons in polar dielectric lattices play in supporting sub-diffraction-limited modes and how the relatively long optical phonon lifetimes can lead to the low optical losses observed within these materials. Based on this overview, the achievements attained to date and the potential technological advantages of these materials are discussed for localized modes in nanostructures, propagating modes on surfaces and in waveguides and novel metamaterial designs, with the goal of realizing low-loss nanophotonics and metamaterials in the mid-infrared to terahertz spectral ranges.
Braic L, Vasilantonakis N, Zou B, et al., 2015, Optimizing strontium ruthenate thin films for near-infrared plasmonic applications, Scientific Reports, Vol: 5, ISSN: 2045-2322
Several new plasmonic materials have recently been introduced in order to achieve better temperature stability than conventional plasmonic metals and control field localization with a choice of plasma frequencies in a wide spectral range. Here, epitaxial SrRuO3 thin films with low surface roughness fabricated by pulsed laser deposition are studied. The influence of the oxygen deposition pressure (20–300 mTorr) on the charge carrier dynamics and optical constants of the thin films in the near-infrared spectral range is elucidated. It is demonstrated that SrRuO3 thin films exhibit plasmonic behavior of the thin films in the near-infrared spectral range with the plasma frequency in 3.16–3.86 eV range and epsilon-near-zero wavelength in 1.11–1.47 μm range that could be controlled by the deposition conditions. The possible applications of these films range from the heat-generating nanostructures in the near-infrared spectral range, to metamaterial-based ideal absorbers and epsilon-near-zero components, where the interplay between real and imaginary parts of the permittivity in a given spectral range is needed for optimizing the spectral performance.
Chen Y, Li X, Sonnefraud Y, et al., 2015, Engineering the Phase Front of Light with Phase-Change Material Based Planar lenses, SCIENTIFIC REPORTS, Vol: 5, ISSN: 2045-2322
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- Citations: 134
Rakovich A, Albella P, Maier SA, 2015, Plasmonic Control of Radiative Properties of Semiconductor Quantum Dots Coupled to Plasmonic Ring Cavities, ACS NANO, Vol: 9, Pages: 2648-2658, ISSN: 1936-0851
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- Citations: 35
Francescato Y, Yang J, Huang M, et al., 2015, General considerations for the miniaturization of radiative antennae, OPTICS EXPRESS, Vol: 23, Pages: 3209-3220, ISSN: 1094-4087
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- Citations: 1
Heath RM, Tanner MG, Drysdale TD, et al., 2015, Nanoantenna Enhancement for Telecom-Wavelength Superconducting Single Photon Detectors, NANO LETTERS, Vol: 15, Pages: 819-822, ISSN: 1530-6984
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- Citations: 21
Perevedentsev A, Sonnefraud Y, Belton CR, et al., 2015, Dip-pen patterning of poly(9,9-dioctylfluorene) chain-conformation-based nano-photonic elements, Nature Communications, Vol: 6, Pages: 1-9, ISSN: 2041-1723
Metamaterials are a promising new class of materials, in which sub-wavelength physical structures, rather than variations in chemical composition, can be used to modify the nature of their interaction with electromagnetic radiation. Here we show that a metamaterials approach, using a discrete physical geometry (conformation) of the segments of a polymer chain as the vector for a substantial refractive index change, can be used to enable visible wavelength, conjugated polymer photonic elements. In particular, we demonstrate that a novel form of dip-pen nanolithography provides an effective means to pattern the so-called β-phase conformation in poly(9,9-dioctylfluorene) thin films. This can be done on length scales ≤500 nm, as required to fabricate a variety of such elements, two of which are theoretically modelled using complex photonic dispersion calculations.
Francescato Y, Giannini V, Maier SA, 2015, Strongly confined gap plasmon modes in graphene sandwiches and graphene-on-silicon, NATO Science for Peace and Security Series B: Physics and Biophysics, Vol: 68, Pages: 493-494, ISSN: 1874-6500
Graphene has emerged as a radically new platform in nanotechnology and its tunable optical and electrical properties make it a material of choice for future nanocircuitry (Vakil and Engheta, Science 332(6035):1291–1294, 2011). A key element towards actual devices is the exploration of graphene nanostructures. For instance, graphene nanoribbons, readily fabricated by electron beam lithography, have been shown to be attractive waveguides for plasmons. These bound surface waves arising from the coupling between light and collective oscillations of the charge carriers exhibit indeed unusually strong confinement in graphene (Nikitin et al., Phys Rev B 84:161407, 2011; Christensen et al., ACS Nano 6(1):431–440, 2012). Our work focuses on the physics and the classification of plasmon waveguide modes in structures consisting of two infinitely long graphene ribbons vertically offset by a gap, a “sandwich” geometry. We find strongly hybridized plasmonic modes, some of which are tightly confined within the gap region, and therefore hold promise for nanodevices (Francescato et al., New J Phys 15(6):063020, 2013). In order to aid the understanding of the fundamental physics of the different classes of waveguide modes encountered, we introduce a convention for plotting the mode spectrum which allows to group the modes by shared characteristics. This representation is particularly useful when coupling occurs, because the mode density increases considerably. In this manner, and varying the critical parameters of width, gap and operation wavelength, different regimes, coupling mechanisms and mode families can be recognized. We confirm our findings by considering experimentally realizable systems with tunable graphene doping in a geometry where a single ribbon is placed on top of a highly doped silicon substrate via a dielectric spacer layer. Remarkably, we show that the new gap modes still survive in the latter case. More, we report on an unprecedented level
Kossoy A, Merk V, Simakov D, et al., 2015, Optical and Structural Properties of Ultra-thin Gold Films, Advanced Optical Materials, Vol: 3, Pages: 71-77, ISSN: 2195-1071
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- Citations: 105
de Abajo FJG, Sapienza R, Noginov M, et al., 2015, Plasmonic and new plasmonic materials: general discussion, FARADAY DISCUSSIONS, Vol: 178, Pages: 123-149, ISSN: 1359-6640
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- Citations: 11
Maier SA, Aouani H, Rahmani M, et al., 2015, Unveiling the origin of third harmonic generation in hybrid ITO-plasmonic crystals, Advanced Optical Materials, ISSN: 2195-1071
Park H-R, Namgung S, Chen X, et al., 2015, Perfect Extinction of Terahertz Waves in Monolayer Graphene over 2-nm-Wide Metallic Apertures, Advanced Optical Materials, ISSN: 2195-1071
High carrier mobility and tunability in graphene enable fundamental studies for plasmonics and various applications. Despite its versatility, however, single-layer graphene (SLG) suffers from poor coupling efficiency to electromagnetic waves, presenting a major challenge for photonic applications. Compared with visible or infrared radiation, terahertz (THz) waves exhibit higher absorption in SLG due to Drude-like intraband transitions, but the wavelength-to-SLG size mismatch becomes even more dramatic. Here, we experimentally demonstrate 99% extinction of THz wave transmission when SLG covers the openings of 2-nm-wide (≈λ/1 000 000) slits through a metal film. By resonantly coupling THz waves through annular nanogaps, the extremely localized fields lead to near-perfect extinction and strong absorption in SLG. Atomic-layer lithography is used to produce these nanometer-wide, millimeter-long gaps over an entire 4-in. wafer. Furthermore, by integrating these devices with an ionic liquid, enhanced intraband absorption in the SLG leads to 80% modulation of THz waves with an operational voltage as low as 1.5 V.
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