| While electronic device miniaturization is close to reaching its potential, photonic devices have unique properties that are yet to be exploited. The manipulation of light in integrated systems similar to that achieved for electrons in semiconductor integrated circuits on nanometer scales is the main topic of this dissertation.; Photonic crystals have emerged as the best potential candidate that can achieve the goal of compact miniaturized photonic chips. The photonic crystal devices exploit defects, in an otherwise periodic lattice designed to exhibit a wide photonic bandgap, to form microcavities or optical waveguides. This dissertation explores the applications of photonic crystal structures in electrically-injected microcavity light sources. The demonstrated single-cell microcavities with superior mechanical and thermal stability exhibit extremely low thresholds <50muA and high output powers ∼50nW, which makes them superior to the electrically injected microcavity light emitters reported so far.; The issues of in-plane integration of microcavity light emitters with photonic crystal-based waveguides are also investigated. Efficient mode-coupling scheme based on photonic crystal defect mode anti-crossings is identified and applied, for the first time, to electrically injected microcavity light sources. The mode-coupling efficiency is measured at 3%, which is comparable to the coupling efficiency of a semiconductor light-emitting diode to a single-mode fiber (4-6%), and it is therefore sufficient for applications of these structures in micro-photonic circuits.; Photonic crystals of air columns in a high refractive index slab are ideal candidates for realizing microfluidic detection as they allow fluids to penetrate the air columns and by changing the refractive index shift the resonant cavity or waveguide defect-modes. This is exploited in two micro-sensing schemes.; The first one involves a branched two-channel photonic crystal based waveguide. The scheme is used successfully to distinguish between isopropanol and xylene (Deltan∼0.13), as the light is guided preferentially through a particular branch when a specific fluid is applied. Introduction of analyte-sensitive polymer membranes onto PC-based microcavities used in the second scheme adds selectivity to highly sensitive detection systems. PC-based microcavity sensors for cation Ca2+ and anion ClO4- detection with sensitivites comparable to the existing state-of-the-art ion-selective sensors (∼10-4M) are demonstrated. |
