Near-field phenomena in resonant and nonlinear photonic nanostructures

Optical nanostructures are manufactured devices composed of two or more constituent materials with characteristic size scales close to but smaller than the optical wavelength (e.g. 50–500 nm). The interaction of an optical wave with such a nanostructure is in most cases qualitatively different than with larger structures. As a result, optical nanostructures enable the study of new and interesting near-field optical physics, and may facilitate novel photonic devices and highly integrated systems. However, the complexity of these interactions means that traditional analytic or approximate solutions are not applicable, and that new accurate numerical electromagnetic analysis tools must be developed. This dissertation presents several specific examples of new electromagnetic analysis tools and the application of these tools to study near-field optical effects in nanostructures and to design and characterize new photonic device structures.; The electromagnetic modeling tools presented in this dissertation are based on the well-established Rigorous Coupled-Wave Analysis technique, and include extensions to investigate ultrashort pulse propagation in nanostructures, as well as to analyze second-harmonic generation in the undepleted-pump approximation. These tools are applied to study the modulation of an ultrashort optical pulse in interacting with nanostructures, as well as to design a quasi-two-dimensional resonant filter based on periodic defects in photonic crystals. In addition, the transverse localization of the optical field in subwavelength periodic nanostructures is extensively studied, with applications to the design of a tunable resonant cavity based on near-field coupling and the enhancement of second-harmonic generation through field localization and engineered phase matching conditions. It is the overall goal of this work—by presenting several concrete examples of useful and novel photonic devices—to illustrate the potential of near-field phenomena in optical nanostructures to provide abundant opportunities for both the study of interesting near-field optical physics and the development of useful optical devices and technologies.; In the future, as the relevant device design and fabrication technologies develop, optical nanostructures hold great promise both as a platform for the miniaturization and large-scale integration of photonic devices and as a tool to investigate new near-field optical physics including nonlinear optical and quantum mechanical phenomena.