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Showing papers on "Plasmon published in 1990"


Journal ArticleDOI
TL;DR: In this paper, the authors calculated the rate of light emission from a scanning tunneling microscope with an Ir tip probing a silver film and found a considerable enhancement of the spontaneous light emission compared with inverse-photo-emission experiments.
Abstract: We have calculated the rate of light emission from a scanning tunneling microscope with an Ir tip probing a silver film. We find a considerable enhancement of the rate of spontaneous light emission compared with, for example, inverse-photoemission experiments. This enhancement is the result of an amplification of the electromagnetic field in the area below the microscope tip due to a localized interface plasmon. One can estimate that one out of ${10}^{4}$ tunneling electrons will emit a photon. We also find that the experimentally observed maximum in the light emission as a function of bias voltage is directly related to the detailed behavior of tip-sample separation versus bias voltage.

257 citations


Journal ArticleDOI
TL;DR: The existence of multipole surface-plasmon modes at simple-metal surfaces is demonstrated both experimentally and theoretically and the multipole mode is shown to be too weak to be observable in electron-loss spectroscopy.
Abstract: The existence of multipole surface-plasmon modes at simple-metal surfaces is demonstrated both experimentally and theoretically. Inelastic reflection electron-scattering experiments on smooth films of K and Na show loss peaks originating from the ordinary surface plasmon as well as from a higher-energy multipole mode. Microscopic density-functional calculations of the electron-loss function reproduce the energy and momentum dispersion of both of these surface modes. For Al, the multipole mode is shown to be too weak to be observable in electron-loss spectroscopy.

144 citations


Journal ArticleDOI
TL;DR: In this article, the surface plasmon is the best known normal mode of the electrons at the surface of simple metals, like Na, K and Cs, and the origin and physical properties of this multipole mode as well as the Surface Plasmon Mode are described.

143 citations


Journal ArticleDOI
TL;DR: Theoretical investigation of the electronic properties of a quasi-one-dimensional electron system at very low temperature for a cylindrical quantum wire and analytical results are in good agreement with the exact results for the model.
Abstract: We present a theoretical investigation of the electronic properties of a quasi-one-dimensional electron system at very low temperature. For a cylindrical quantum wire the electron-impurity interaction and the electron-electron interaction is calculated for a two-subband model. Our analytical results for the electron-impurity and the electron-electron interaction are in good agreement with the exact results for our model. Analytical results for the band bending due to the filling of the lowest subband are evaluated. Within our analytical results we discuss various aspects of the electronic properties of the semiconductor quantum wire: screening (intrasubband and intersubband plasmons), shallow impurity states (screened and unscreened), and mobility (ionized-impurity scattering and interface-roughness scattering). Analytical expressions are given for the dispersion of plasmons, the binding energies of shallow impurities, and the mobility. Our results on intersubband plasmons are compared with experiments.

136 citations


Journal ArticleDOI
26 Nov 1990
TL;DR: In this article, a strongly directional emission of defined polarization can be achieved from conventional AlGaAs/GaAs double heterostructure surface emitting LEDs via coupling to surface plasmons.
Abstract: We show for the first time that strongly directional emission of defined polarization can be achieved from conventional AlGaAs/GaAs double heterostructure surface emitting LEDs via coupling to surface plasmons. By microstructuring the surface, we have fabricated LEDs with a beam divergence of less than 40 and a drastically increased quantum efficiency. We prove that surface plasmon excitation aid emission mechanism has the potential to overcome basic external quantum efficiency losses and to improve the performance of LEDs.

117 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used a grating to provide the necessary extra momentum to accelerate the plasmon-polaritons at a metal-air boundary, and obtained a p-s conversion of up to 66% for silver-coated gratings of appropriate depth.
Abstract: Surface plasmon-polaritons may be excited by photons at a metal-air boundary if a grating is used to provide the necessary extra momentum. Rotation of the grating so that the grooves are no longer perpendicular to the plane of incidence reduces the coupling efficiency while at the same time producing some s-polarised radiation in the reflected beam. When the grooves are at 45° to the plane of incidence maximum p-s conversion is obtained. Conversion efficiencies of up to 66% have been recorded for silver-coated gratings of appropriate depth. By scanning the angle of incidence and using a crossed polariser on the detector a strong resonance peak is observed. The application of this phenomenon to optical sensing is considered.

110 citations


Journal ArticleDOI
TL;DR: In this article, the polarization-selective evanescent field coupling of an optical wave in a 1.3-mu m, fiber-to-surface, plasmon polaritons supported by a thin aluminium film was investigated theoretically and experimentally.
Abstract: The polarization-selective evanescent field coupling of an optical wave in a 1.3- mu m, fiber to surface, plasmon polaritons supported by a thin aluminium film was investigated theoretically and experimentally. Good agreement was observed between the theoretically predicted conditions for efficient coupling and the experimentally determined conditions for high TM/TE extinction ratio of the optical field. The use of silver and chrome in place of aluminum was investigated experimentally at 1.3 mu m, and 0.63- mu m devices using aluminium were also studied. The results led to the realization of readily manufacturable, high-extinction-ratio (>50 dB) low-loss ( >

103 citations


Patent
21 Mar 1990
TL;DR: In this article, a high-speed light modulator employing surface plasmon wave coupling is proposed, where a metal dielectric interface is positioned adjacent to and externally of a waveguide carrying totally internally reflected light waves.
Abstract: A high-speed light modulator employing surface plasmon wave coupling comprises a metal-dielectric interface positioned adjacent to and externally of a waveguide carrying totally internally reflected light waves. A high frequency voltage applied to the interface causes the dielectric, in the preferred case an ultra-fast electro-optic polymer, to resonate, generating a surface plasmon wave at the interface. The plasmon wave couples with the evanescent wave portion of the light waves in the waveguide. The output intensity of the light waves varies inversely with the strength of coupling between the light wave and surface plasmon wave modes. The modulator eliminates bulk and alignment problems associated with state of the art modulators and can be employed in integrated optic circuits.

96 citations


Journal ArticleDOI
TL;DR: This is an experimental proof that the Coulomb interaction between neighboring wires is weak and the excitations represent confined plasmons of the individual wires.
Abstract: Plasmon excitations for a lateral superlattice of quantum wires in a modulation-doped GaAs/(AlGa)As multiple-quantum-well system have been investigated by resonant inelastic light scattering. The Raman spectra exhibit a set of resonances with a strongly anisotropic dispersion. For momentum transfer parallel to the wires a significant dispersion is observed; perpendicular to the wires the dispersion is nearly flat. This is an experimental proof that the Coulomb interaction between neighboring wires is weak and the excitations represent confined plasmons of the individual wires

70 citations


Journal ArticleDOI
TL;DR: In this article, photoabsorption spectra were reported for two, eight-electron, closed-shell clusters, Cs8 and Cs10O, with a multi-peak structure which was interpreted to be due to a plasmon excitation plus one or more plasm-enhanced oneelectron excitations.

60 citations


Journal ArticleDOI
TL;DR: In this article, surface plasmon microscopic pictures recorded as a function of the angle of incidence of the coupling laser beam can be quantitatively evaluated and yield optical thicknesses of ultrathin coatings with an areal resolution of 5×5 μm2.
Abstract: Surface plasmon microscopic pictures recorded as a function of the angle of incidence of the coupling laser beam can be quantitatively evaluated and yield optical thicknesses of ultrathin coatings with an areal resolution of 5×5 μm2. This is demonstrated for a lipid monolayer transferred to a solid support in its phase transition region. The coexisting amorphous and crystalline domains can be analyzed simultaneously.

Journal ArticleDOI
TL;DR: The optical properties of extremely heavily doped n−GaAs are examined in this paper, where it is shown that the low energy edge of the photoluminescence indicates a band-edge narrowing proportional to ∼n 1/3 and equal to ∼200 meV at the highest electron concentration.
Abstract: The optical properties of extremely heavily doped n‐GaAs are examined. Metastable electron concentrations up to 3.2×1019 cm−3 were produced by pulsed‐laser annealing of Si‐implanted GaAs. These very heavily doped layers give plasmon Raman shifts up to 1700 cm−1 and photoluminescence bandwidths of greater than 410 meV. The low‐energy edge of the photoluminescence indicates a band‐edge narrowing proportional to ∼n1/3 and equal to ∼200 meV at the highest electron concentration.

Journal ArticleDOI
TL;DR: In this paper, the dielectric function, the reflectivity and the optical conductivity have been obtained from a combination of these experimental data in a wide energy range, interpreted in terms of optical phonons, free-carrier absorption, transitions across the charge-transfer gap, further interband transitions, low-lying core-level excitations, excitonic transitions and valence conservingd-d transitions within the Cu 3d shell combined with O 2p intraband transitions.
Abstract: Electronic excitations with polarization parallel to the CuO2-planes in single-crystalline YBa2Cu3O7 and YBa2Cu3O6 have been investigated by optical reflectance and by highenergy electron energy-loss spectroscopy in transmission in the energy ranges from 50 meV to 6 eV and 0.2 eV to 150 eV, respectively. From a combination of these experimental data the dielectric function, the reflectivity and the optical conductivity have been obtained in a wide energy range. The observed spectra are interpreted in terms of optical phonons, free-carrier absorption, transitions across the charge-transfer gap, further interband transitions, low-lying core-level excitations, excitonic transitions and valence conservingd-d transitions within the Cu 3d shell combined with O 2p intraband transitions. The charge carrier plasmon and the 4 eV-excitation in YBa2Cu3O6 show quadratic dispersions in momentum transfer. From the dispersion constant of the plasmon a mean value of the Fermi velocity of the charge carriers parallel to the CuO2 planes has been derived.

Journal ArticleDOI
TL;DR: It is found that for wave vectors directed close to the direction of the superlattice axis, the plasmon mode remains {ital below} the superconducting gap edge, and the Anderson-Higgs mechanism does not give rise to a massive collective mode as it does in the bulk three-dimensional system.
Abstract: We calculate the collective-mode spectrum for a layered superconductor structure. We find that for wave vectors directed close to the direction of the superlattice axis, the plasmon mode remains {ital below} the superconducting gap edge (i.e., the Anderson-Higgs mechanism does not give rise to a massive collective mode as it does in the bulk three-dimensional system). We also find a clear signature of superconductivity in the form of a unique line splitting in the collective-mode spectrum as the plasmon crosses the superconducting gap. Experimental implications are discussed.

Journal ArticleDOI
TL;DR: In this article, the diffraction and absorption losses of plasmon surface waves propagating along a metallic grating are investigated numerically as a function of the groove depth and a periodicity of diffraction losses is found.
Abstract: Diffraction and absorption losses of plasmon surface waves (PSW) propagating along a metallic grating are investigated numerically as a function of groove depth. A periodicity of diffraction losses is found to exist. The energy flow distribution (EFD) above and inside the grooves is calculated and a similarity between the PSW on shallow and deep gratings is established above the grooves, while inside the grooves of deep gratings totally hidden curls in EFD are found to form.

Journal ArticleDOI
Fraser Burton1, S.A. Cassidy1
TL;DR: In this article, a numerical method was used to solve the plasmon-polariton dispersion relation for a planar thin-metal-film geometry, and a complete description of the variation of effective-mode index and propagation length with metal thickness and cover index was presented for all four modes.
Abstract: A versatile numerical method is used to solve the plasmon-polariton dispersion relation for a planar thin-metal-film geometry. A complete description of the variation of effective-mode index and propagation length with metal thickness and cover index is presented for all four modes. The spatial distribution of these modes is calculated explicitly. The effects of a nonideal metal film and of dielectric loss in the cover material is considered. >

Journal ArticleDOI
TL;DR: In this paper, a method to determine optical constants of metal systems using electron energy loss spectroscopy (EELS) in the reflection mode is reported, where the data treatment involves isolating the loss function from the experimental EEL spectrum by deconvolution of the surface plasmon contribution from the data obtained with a high energy primary beam using data acquired with a low-energy primary beam at a grazing incidence angle.

Patent
18 Oct 1990
TL;DR: In this article, the plasmon resonance effect was used to enhance the effect of solar energy on a solar responsive electrode of a photochemical battery, and to inhibit the passage of ultraviolet light through a sunscreen.
Abstract: Methods and apparatus provided with selected nanoparticles that exhibit the plasmon resonance effect to enhance photoprocesses. In a first embodiment, such nanoparticles are used in a method of forming an integrated circuit; and in additional embodiments, the nanoparticles are used to increase the catalytic effect of a metal catalyst to increase the rate at which molecules absorb light, to accelerate the reduction of carbon dioxide to formic acid, to accelerate the decomposition of pollutants, and to accelerate the reaction of two reactants to produce a fuel. Additional embodiments utilize the plasmon resonance effect to enhance the effect of solar energy on a solar responsive electrode of a photochemical battery, and to inhibit the passage of ultraviolet light through a sunscreen. Also, in accordance with the present invention, nanoparticles that exhibit the plasmon resonance effect are used to improve a test for a solution for a bio-agent, and to develop fingerprints on a surface.

Proceedings Article
Jagdeep Shah1
21 May 1990
TL;DR: Optical spectroscopy of semiconductors has proved to be an extremely useful tool in studying electronic states (band structure, excitons, defects) as well as elementary excitations (phonons, plasmons, and their coupled modes) in semiconductor as mentioned in this paper.
Abstract: Optical spectroscopy of semiconductors has proved to be an extremely useful tool in studying electronic states (band structure, excitons, defects) as well as elementary excitations (phonons, plasmons, and their coupled modes) in semiconductors. While this aspect of optical spectroscopy is well known, there is another strength of optical spectroscopy that is not as well known. Optical spectroscopy also provides a powerful technique for investigating nonequilibrium phenomena in semiconductors. This aspect of optical spectroscopy has led to many interesting developments over the last 20 years.

Journal ArticleDOI
TL;DR: Calcul du spectre d'excitation collective d'un superreseau a puits quantique lateral dans la limite d'effet tunnel faible et dans l'approximation de la phase aleatoire.
Abstract: Calcul du spectre d'excitation collective d'un superreseau a puits quantique lateral dans la limite d'effet tunnel faible et dans l'approximation de la phase aleatoire. On obtient la relation de dispersion des excitations intra et inter-sous-bandes, et on considere le couplage de mode entre elles. Analyse de l'influence de l'effet tunnel sur la dispersion des plasmons

Journal ArticleDOI
Shinji Hayashi, R Koga, M Ohtuji, K Yamamoto, Minoru Fujii1 
TL;DR: In this paper, the authors investigated the optical extinction spectra of gas-evaporated Ag small particles and found that the extinction spectrum exhibits a long tail at the long-wavelength side of the surface plasmon resonance.

Journal ArticleDOI
TL;DR: In this article, the authors describe the theory, design, and performance of a surfaceplasmon-polariton (SPP) assisted Raman scattering instrument that exploits the Kretschmann geometry and allows the entire SPP emission cone to be collected, thus optimizing the detected Raman intensity.
Abstract: We describe the theory, design, and performance of a new surface‐plasmon‐polariton‐(SPP) assisted Raman scattering instrument that exploits the Kretschmann geometry. In contrast to previous methods, our device allows the entire SPP emission cone to be collected, thus optimizing the detected Raman intensity. This advantage makes surface Raman scattering from adsorbates on relatively smooth or single‐crystal silver films possible with routine optics and electronics in the rest of the system. We demonstrate the concept with data acquired from a monolayer of paranitrosodimethylanaline (pNDMA) on nearly smooth polycrystalline Ag and single‐crystal Ag(111) with air or liquid as the ambient medium.

Journal ArticleDOI
TL;DR: A quantum yield approaching 2 x 10(-8) at a photon fluence of 10 MW/cm (2) from a two-photon process was observed, which is 5 x 10(3) higher than that of the bulk emission measured for the same film at the same power fluence.
Abstract: We report the enhancement of multiphoton photoelectric emission, from a thin silver film, by surface plasmons excited at the single-metal–vacuum interface. The surface plasmons are resonantly pumped by femtosecond laser pulses in the Kretchmann attenuated-total-internal-reflection configuration. A quantum yield approaching 2 × 10−8 at a photon fluence of 10 MW/cm2 from a two-photon process was observed, which is 5 × 103 higher than that of the bulk emission measured for the same film at the same power fluence.

Journal ArticleDOI
TL;DR: The plasmon dispersion relation of a quantum wire is derived by solving Maxwell's equations for an anisotropic dielectric waveguide including retardation effects and the group velocity of the one-dimensional electron gas is found to be finite and given by the Fermi velocity.
Abstract: The plasmon dispersion relation of a quantum wire is derived by solving Maxwell's equations for an anisotropic dielectric waveguide including retardation effects. In the long-wavelength limit, and for the extreme quantum limit, the group velocity of the one-dimensional electron gas is found to be finite and given by the Fermi velocity.

Journal ArticleDOI
TL;DR: In this article, the surface plasmon-polariton (SPP) waves which are supported by the thin chromium films are optically excited by evanescent field interaction with the propagating fundamental fiber mode and utilized as the polarization selective mechanism.
Abstract: High-quality optical fiber polarizers have been fabricated by depositing thin chromium films thermally onto polished fibers. Surface plasmon-polariton (SPP) waves which are supported by the thin chromium films are optically excited by evanescent field interaction with the propagating fundamental fiber mode and utilized as the polarization selective mechanism. Transverse-magnetic-like polarized light is extinguished when precise phase-matching conditions with the symmetric-bound SPP mode are achieved. The transverse-electric-like polarization, on the other hand, passes through with minimal losses. Devices with polarization extinction ratio in excess of 50 dB and insertion losses less than 1 dB are demonstrated. >

Journal ArticleDOI
TL;DR: In this article, high-resolution electron energy loss spectroscopy (HREELS) has been used to study the (100) surface of n-type InSb (Te doped, n ≈ 1 x 1018 cm-3).

Journal ArticleDOI
Bernard Jusserand1, D. Richards, G. Fasol, G. Weimann, W. Schlapp 
TL;DR: In this article, the electronic Raman scattering results on a single two-dimensional electron gas confined in a single quantum well, measured as a function of the scattering geometry and in the presence of additional illumination, were analyzed.

Journal ArticleDOI
TL;DR: Observation of excitations with frequency much lower than the frequency of the superconducting gap {Delta}/{h bar} is possible by use of a grating and the same far infrared or microwave techniques used for detection of the plasmons in semiconductor microstructures.
Abstract: Long-wave excitations in Josephson arrays are investigated. The existence of excitations with square root or acoustic dispersion law, like plasmons in two-dimensional electron gas, is predicted. Observation of such excitations with frequency much lower than the frequency of the superconducting gap {Delta}/{h bar} is possible by use of a grating and the same far infrared or microwave techniques used for detection of the plasmons in semiconductor microstructures.

Journal ArticleDOI
TL;DR: It is shown that in the nonretarded regime, the frequency of the long-wavelength surface plAsmon of a free-electron metal is directly related to the overlap of the metal's unperturbed electron density and the normalized, fluctuating potential of the surface plasmon.
Abstract: It is shown that in the nonretarded regime, the frequency of the long-wavelength surface plasmon of a free-electron metal is directly related to the overlap of the metal's unperturbed electron density and the normalized, fluctuating potential of the surface plasmon. This result directly expresses the idea that the surface plasmon's frequency depends on the efficiency with which its electric potential energy can be interchanged with electron kinetic energy. It shows that a negative surface-plasmon dispersion coefficient can be interpreted in terms of decreasing overlap of the fluctuating potential and the unperturbed electron density, as the plasmon wave vector increases.

Journal ArticleDOI
TL;DR: The coupling mechanisms between longitudinal-optical phonons and electronic excitations in n-type ZnSe layers were investigated with Raman spectroscopy in conjunction with transport measurements and values of free-electron concentration as a function of temperature were established.
Abstract: The coupling mechanisms between longitudinal-optical phonons and electronic excitations in n-type ZnSe layers were investigated with Raman spectroscopy in conjunction with transport measurements The layers were grown by molecular-beam epitaxy and were intentionally doped below the Mott criterion for the insulator-metal transition The nature of the electron-phonon interaction is determined by the degree of electron localization, which was effectively changed by temperature and donor concentration The longitudinal-optical phonons couple to plasmons when electrons are thermally excited into the conduction band and to a continuum of electronic excitations when electrons are localized in an impurity band or at donor sites In both cases unbound phonons are observed From the renormalized phonon frequencies at high temperature, values of free-electron concentration as a function of temperature were established They are in excellent agreement with Hall-effect determinations At low temperatures the phonon Raman profiles are asymmetric and show Fano-type line shapes The electronic continuum responsible for the phonon self-energies at low temperature was identified as Raman scattering by bound electrons