Fabrication of two-dimensional photonic crystal single-defect cavities and their characterization by elastic scattering

The subject of this thesis is fabrication process development and characterization of two-dimensional photonic crystal single defect cavities. These devices are potential candidates to become one of the building blocks of photonic integrated circuits, which are expected to be valuable in optical telecommunications.; Photonic crystal cavities were designed based on results from the computer simulations, which were obtained from various sources. To make the cavities, a fabrication process, which involved sub-micron patterning and etching techniques, was developed. High quality structures were obtained after the optimization of the different parameters of the process.; Photoluminescence spectral measurements were used to observe the signature of the cavity mode in the structure. The theory of spontaneous emission in inhomogeneous media is presented to explain the experimental observations. This theory is applied to the photoluminescence exhibited by the semiconductor materials. From the photoluminescence spectral measurements, the cavity tuning and quality factor Q can be estimated. Absorption and Radiation loss mechanisms present in the cavities were separated by performing a curve fit of the loss rate, 1/Q, versus the wavelength-dependent absorption coefficient of the material used. By extrapolating this curve to zero absorption, the radiation loss rate 1/Q_rad of the cavity is obtained.; An alternative characterization method based on elastic scattering of light was implemented. This method consists of the measurement of the spectrum of the light scattered from the cavity when a tunable light source is focused onto it. The wavelength dependence of the scattered light intensity can be used to estimate the cavity quality factor, Q, in a way similar to the photoluminescence spectrum measurements. This experimental method is useful to determine the maximum possible Q that occurs when the cavity does not absorb light at the cavity resonance wavelength.