| Optical microcavities, which confine light to small dimensions by total internal reflection (TIR), possess unique characteristics that depend on its morphology. The following dissertation presents experimental results from two-dimensional optical microcavities of various cross-sectional shapes. This includes a novel design, specifically a spiral-shaped InGaN multiple-quantum well microcavity, which is the first known microdisk device to produce unidirectional lasing emission from a single output beam when selectively optically-excited with a ring-shaped beam. The spiral microcavities also perform successfully under pulsed as well as continuous-wave current-injection conditions. Furthermore, the output intensity of the spiral microlaser is shown to increase with the addition of semicircle-based microdisks, which serve as optical amplifiers. Square-shaped dye-doped polymer micro-pillars are also examined which could be useful as add/drop filters for wavelength-division-multiplexing. Lasing emission is detected from the square corners due to completely TIR-confined modes which correspond to ray orbits with an incident angle theta inc at or near 45°. Additionally, surprising strong emission from the sidewalls is observed, which is associated with modes that are only partially TIR-confined but still have a high enough reflection coefficient to be sustained. |
