Optical antennas on substrates and waveguides

Currently our society faces two large challenges: a challenge in information technology and a challenge in energy. For both these problems possible solutions are sought in the efficient manipulation and control of light. For information technology, light has the large advantage that signals can be multiplexed by encoding information in different wavelengths, allowing a single fiber to carry up to Terabytes/s of information. As regards energy, if we would be able to harvest just 0.02% of the solar energy incident on the entire earth yearly, this would completely fulfill our energy demands. Both challenges require exquisite control over how light propagates, and over how light interacts with matter through emission, absorption and scattering. This control has been vastly improved in the last decade by recently developed new design ideas and fabrication possibilities for nanophotonic structures. In order to contribute to science in this specific direction, in this thesis, we explore ways in which we can more intuitively understand and design complex nanophotonic structures that are composed of metal scatterers embedded in dielectric structures. Metal scatterers are currently studied very intensively in the field of "plasmonics". Especially structures made of noble metals can act as very strong "antennas" that strongly scatter and confine light. In this work we specifically target the question how antennas can be integrated with dielectric structures such as waveguides which can losslessly carry information as light, which, could be the next step of the revolution in information technology started by optical fibers.