Showing papers on "Surface plasmon resonance published in 1983"

Experimental Observation of Long-Range Surface Plasmon Polaritons

Abstract: ATR technique (glass prism-index matching oil-Ag-CaF 2 single crystal) has been used to observe long-range surface plasmon polaritons discussed recently by Sarid. At 632.8 nm, we have successfully observed the sturface plasmon polaritons in the propagation distance of 105 µm.

Photoacoustic study of plasmon resonance absorption in a diffraction grating

Abstract: Plasmon resonance absorption in a 520-line/mm silver-coated diffraction grating was measured as a function of the angle of ruling orientation relative to the plane of photon incidence by a photoacoustic method. The experimental results of absorptance changes as a function of ruling orientation were found to be consistent with predictions from the first-order perturbation theory for roughness-induced photoabsorption. A discrepancy was found, however, between the absorptance values observed and the values calculated from the first-order theory.

Resonance fluorescence of a two-level atom near a metal surface. Technical report

Abstract: A derivation of surface-dressed optical Bloch equations, involving a treatment of surface-reflected photons and a surface plasmon resonance, is presented for a collision-damped two-level atom near or adsorbed on a metal surface Effects of the laser bandwidth are included by means of a phase-diffusion model for the driving field In the weak-field or large detuning limit, the population inversion and resonance fluorescence spectrum are obtained analytically These quantities along with the surface-induced phase-decay constant of the adatom show strong oscillatory behavior as a function of the adatom-surface distance

Surface Plasmon Enhanced Vibrational Spectra of Monolayer Assemblies on Gratings and Rough Metal Surfaces

Abstract: The vibrational spectra of monolayer assemblies of cadmium arachidate on smooth and rough silver substrates were obtained by surface infrared and surface plasmon enhanced Raman spectroscopy. The assemblies were laid down by the Langmuir-Blodgett deposition technique. For Raman scattering the intensity of the incident light was enhanced by grating coupling to surface plasmon optical modes of the metal or to localized plasmon modes in the case of rough surfaces. It was found that the different vibrational frequency regions corresponding, for example, to C-C and C-H stretching modes, were enhanced by selecting different scattering angles for collecting the inelastically scattered light. The Raman spectra of monolayer assemblies in contact with silver islands showed evidence of conformational disorder, i.e., the alkyl chains of some molecules were not in the all-trans configuration. In contrast, the infrared spectra did not show evidence of similar disorder. These observations were explained by assum...

Low-Energy Electron Energy-loss Spectra Associated with Reconstructed Structure on Si(111) Surface

Abstract: Low-energy electron energy-loss spectra from the Si(111) surface were obtained under a surface wave resonance condition under which the wave vector of diffracted electrons is parallel to a row of the 1/7-order superlattice rods in 7×7 structure: A peak related to surface dangling bond at 1.5 eV in the energy-loss value ΔE, and a peak due to the excitation of surface plasmon at ΔE=8.5 eV are enhanced at each height. Surface plasmon peak shifts to 10.5 eV when the condition is not satisfied. When the surface changes from a 7×7 structure to a 1×1, the decrease in these peak heights is also observed.

Photoacoustic study of phase correlation of surface plasmons in a diffraction grating

Abstract: .Nonradiative surface plasmons may be excited in a metal-coated diffraction grating by either p­ or s-polarized photons if the ruling is oriented neither perpendicular nor parallel to the plane of photon incidence. Phase correlation between these surface plasmons in a 520-line/mm Ag-coated diffraction grating was observed by measuring absorption of elliptically polarized 633-nm photons at the plasmon resonance angle. The absorption measurements were made by using a photoacoustic technique. The experimental results were analyzed by a first-order perturbation theory of photoab­ sorption in a rough surface. This allowed us to determine the phase difference between surface plasmons excited by p- and s-polarized photons. I. INTRODUCTION In contrast to conventional spectroscopic methods in which light intensities are measured outside the sample under study, photoacoustic methods 1 measure absorption of photons by probing heat generation occurring inside the sample as a result of nonradiative dissipation of excited states created by incident photons. This makes possible new experimental studies which have been difficult to per­ form by conventional experimental methods. In recent years we have used 2 - 6 this photoacoustic technique to study excitation and relaxation of surface plasmons 7 in metals by using the attenuated-total reflection (ATR) and grating methods. Most recently, we have investigated 6 plasmon resonance absorption in a Ag-coated diffraction grating as a function of the ruling orientation relative to the plane of incidence. Such a study has been hitherto dif­ ficult to perform by conventional spectroscopic methods because photons are diffracted out of the plane of in­ cidence. Surface plasmons may be excited in a diffraction grating by both p- and s-polarized photons if the ruling is neither perpendicular nor parallel to the plane of in­ cidence. These surface plasmons are excited at the same angle of photon incidence for both p and s photons and propagate in the same direction along the grating surface and are thus coherent to each other. Therefore, if they are excited simultaneously by photons having both p and s components in a certain phase relation, the phase correla­ tion of the plasmons may be observed directly in the reso­ nance absorptance values. In this paper we report experi­ mental results of this phase correlation for surface plasmons in a Ag-coated shallow diffraction grating. The plasmon resonance absorption was measured by the same photoacoustic method as in our previous studies 2 - 6 as a function of the relative phase between p and s components of elliptically polarized incident photons. The experimen­ tal results were analyzed numerically with the use of a first-order perturbation theory 8 of photoabsorption in a rough surface. This allowed us to determhle the phase difference between surface plasmons excited by p- and s­ polarized photons.

The Effect of Applied Potential on Plasmon Resonance Bands of Nanoscopic Silver Particles Adsorbed on Transparent Electrodes

Abstract: The plasmon resonance spectra of nanoscopic silver particles adsorbed on transparent semiconductor electrodes in contact with eight aqueous electrolytes (KCl, KBr, KI, NaCl, NaBr, NaI, NaClO4, and KPF6) have been examined. In all electrolytes, the plasmon resonance bands are red-shifted and decreased in intensity as the applied potential is made more positive. The degree of the potential-induced spectral changes depends on the electrolyte type and concentration. The change in plasmon absorption band is largest for the higher concentration. At constant concentration, the potential-induced spectral changes are largest in the presence of I - , Cl - and Br - anions and smallest in the presence of PF6 - and ClO4 - anions. The largest effects for particles in contact with I - , Cl - and Br - anions may arise from more severe reduction in electron mean free lifetime and/or the formation of a metal-adsorbate complex which is highly absorbing in the spectral region of the plasmon resonance band.

Spectrum of surface quantum plasmon resonances in high-magnetic field

Abstract: For long wavelengths, there is an undamped quantum-type plasmon resonance (QPR) near each higher multiple of the cyclotron frequency n ω c ( n ⩾2), for a bulk quantum plasma in the presence of an external magnetic field. This mode involves the coupling between magnetoplasmons and single-particle excitations of the Landau levels of the electron gas. In this paper, the nonlocal surface QPR is examined under high-magnetic field conditions, with the electrons occupying the lowest Landau level only. The magnetic field is perpendicular to the surface of the plasma. The surface QPR is evaluated in the long-wavelength limit, for the degenerate case. It is shown that this mode is naturally damped.