Fundamentals of Plasmonics.- Electromagnetics of Metals.- Surface Plasmon Polaritons at Metal / Insulator Interfaces.- Excitation of Surface Plasmon Polaritons at Planar Interfaces.- Imaging Surface Plasmon Polariton Propagation.- Localized Surface Plasmons.- Electromagnetic Surface Modes at Low Frequencies.- Applications.- Plasmon Waveguides.- Transmission of Radiation Through Apertures and Films.- Enhancement of Emissive Processes and Nonlinearities.- Spectroscopy and Sensing.- Metamaterials and Imaging with Surface Plasmon Polaritons.- Concluding Remarks.

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Plasmonics: Fundamentals and Applications

Surface plasmons (SPs) are coherent oscillations of conduction electrons on a metal surface excited by electromagnetic radiation at a metal -dielectric interface. The growing field of research on such light -metal interactions is known as ‘plasmonics’. 1-3 This branch of research has attracted much attention due to its potential applications in miniaturized optical devices, sensors, and photonic circuits as well as in medical diagnostics and therapeutics. 4-8

Nanostructured plasmonic sensors.

IN two previous notes1, Prof. Max Born and I have shown that one can obtain a theory of superconductivity by taking account of the fact that the interaction of the electrons with the ionic lattice is appreciable only near the boundaries of Brillouin zones, and particularly strong near the corners of these. This leads to the criterion that the metal should be superconductive if a set of corners of a Brillouin zone is lying very near the Fermi surface, considered as a sphere, which limits the region in the momentum space completely filled with electrons.

On the theory of superconductivity

The presence of tiny holes in an opaque metal film, with sizes smaller than the wavelength of incident light, leads to a wide variety of unexpected optical properties such as strongly enhanced transmission of light through the holes and wavelength filtering. These intriguing effects are now known to be due to the interaction of the light with electronic resonances in the surface of the metal film, and they can be controlled by adjusting the size and geometry of the holes. This knowledge is opening up exciting new opportunities in applications ranging from subwavelength optics and optoelectronics to chemical sensing and biophysics.

Light in tiny holes

Annual review of condensed matter physics

The generation of surface plasmon polaritons (SPPs) at isolated nanoholes in 100nm thick Au films is studied using near-field scanning optical microscopy. Finite-difference time-domain calculations, some explicitly including a model of the scanning tip, are used to interpret the results. We find the holes act as point-like sources of SPPs and demonstrate that the interference between the SPP and a directly transmitted wave allows determination of the wavelength, phase, and decay length of the SPP. The near-field intensity patterns can be manipulated by varying the angle and polarization of the incident beam.

Surface plasmons at single nanoholes in Au films

A new electroless plating method was used to deposit palladium nanotubes within the pores of track-etched polycarbonate membranes. The morphology of the deposited palladium nanostructures were characterized with the use of field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectrometry (EDX), and transmission electron microscopy (TEM). The largely expanded surface area and granular nature of the nanotubes make them ideal for applications that require high surface area. One of the applications investigated here is hydrogen sensing. Palladium nanotubes excel in high sensitivity, low detection limit, and fast response times in hydrogen sensing compared to sputtered Pd thin film on glass. The response time ranges from a few seconds to tens of seconds depending on the concentration of hydrogen. The hydrogen sensing behavior can be understood with the Langmuir adsorption isotherm theory at very low hydrogen concentration. The high sensitivity and fast response time in the nanotube imbe...

Fabrication of Palladium Nanotubes and Their Application in Hydrogen Sensing

The superconducting phase diagram of ${\mathrm{MgB}}_{2}$ was determined from magnetization, magnetotransport, and single-crystal specific-heat measurements. A zero-temperature in-plane coherence length of 9.4 nm is determined. The superconducting anisotropy \ensuremath{\gamma} increases from a value around 2 near ${T}_{c}$ to above 4.5 at 22 K. For $H\ensuremath{\parallel}c$ a pronounced peak effect in the critical current occurs at the upper critical field. Evidence for a surface superconducting state is presented for $H\ensuremath{\parallel}c$ that might account for the widespread in reported values of \ensuremath{\gamma}.

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Superconducting transition and phase diagram of single-crystal MgB 2

The consequences of a recently proposed model [A. Rydh, \"O. Rapp, and M. Andersson, Phys. Rev. Lett. $83,$ 1850 (1999)] for the vortex-liquid resistivity close to a vortex liquid-to-glass transition are analyzed in detail. We find a detailed quantitative agreement between the model and resistivity measurements on disordered, optimally doped ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ single crystals. For temperatures below the superconducting transition temperature, a scaling of all measured resistivity curves in magnetic field $(0lBl~12 \mathrm{T})$ is obtained. Possible ways of slightly modifying the model in order to fully describe resistivity measurements on more anisotropic underdoped oxygen-deficient ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ single crystals are suggested. The physical interpretation of the model and its connection to other models of the vortex-liquid resistivity are discussed. In particular, we find close connections to vortex glass models and to a generalized Coulomb gas model.

Scaling of the vortex-liquid resistivity in optimally doped and oxygen-deficient YBa 2 Cu 3 O 7-δ single crystals

A modified vortex glass correlation length is introduced to give a consistent description of the field and temperature dependence of the resistivity in the vortex liquid regime of high-T-c superconductors. The proposed model explicitly takes into account both thermal energy and a characteristic mean pinning energy, U-0(B, T). We find good agreement between the model and our measurements on twinned single crystals of YBa2Cu3O7-delta sand thin film Tl2Ba2CaCu2O8+delta.

Andreas Rydh

Papers

Surface plasmons at single nanoholes in Au films

Fabrication of Palladium Nanotubes and Their Application in Hydrogen Sensing

Superconducting transition and phase diagram of single-crystal MgB 2

Scaling of the vortex-liquid resistivity in optimally doped and oxygen-deficient YBa 2 Cu 3 O 7-δ single crystals

Consistent description of the vortex glass resistivity in high-T-c superconductors