A surface plasmon is light that is bound to a metal surface. The main merit of a surface plasmon is that is provides confinement below the diffraction limit. In this thesis, we first study the... Show moreA surface plasmon is light that is bound to a metal surface. The main merit of a surface plasmon is that is provides confinement below the diffraction limit. In this thesis, we first study the excitation and scattering of surface plasmons by subwavelength holes in the metal. Thereafter we show that an array of these hole acts as a surface plasmon laser when the surface plasmons are sufficiently amplified using a semiconductor gain medium Show less
This thesis describes coupling of light to periodic structures. A material is patterned with a regular pattern on a length scale comparable to the wavelength of light. With these structures, light... Show moreThis thesis describes coupling of light to periodic structures. A material is patterned with a regular pattern on a length scale comparable to the wavelength of light. With these structures, light can be manipulated very precisely. The structures find applications in semiconductor lasers, light emitting diodes (LEDs), photovoltaic cells, and detectors of light. A periodic array of holes in a layer of semiconductor or in a thin metal film causes a coupling between the incident light and light that is trapped inside the layer. This coupling can be studied by measuring the reflection and transmission. The environment has an important role here; e.g. placing glass antennas in the holes can increase the coupling between light and plasmons. A thin, superconducting wire can be used as a detector of light. To increase the surface area, the wire is folded into a meander. The optical properties of this detector are very dependent on the polarization, due to the regular periodic structure of the meander. Moreover, we found that the absorption of a very thin absorbing layer can be almost 100%, when it is illuminated under the right angle, from the substrate. This can be used to increase the efficiency of the detectors. Show less
A surface plasmon is a purely two-dimensional electromagnetic excitation bound to the interface between metal and dielectric and quickly decaying away from it. A surface plasmon is able to... Show moreA surface plasmon is a purely two-dimensional electromagnetic excitation bound to the interface between metal and dielectric and quickly decaying away from it. A surface plasmon is able to concentrate light on sub-wavelength scales __ a feature that is attractive for nano-photonics and integrated optics. Light couples to a surface plasmon via surface roughness or an irregularity and vice versa. Most experimental and theoretical work on surface plasmons is concerned with metallic structures that contain one or two-dimensional arrays of close-lying sub-wavelength holes or slits. In this thesis a much simpler system of only a few parallel sub-wavelength-wide slits is used as a playground for surface-plasmon studies. Amplitude and phase characteristics of the light-plasmon-slit interaction events, like coupling, reflection and plasmon hopping over a slit, are studied via corresponding interference phenomena. Moreover, a single subwavelength-wide slit displays a wave-plate behavior, as a result of a finite conductivity of the metal film. Show less
