Techniques based on optical, x ray, and electron microscopy measurements are applied to characterized a wide variety of semiconductor multilayer structures. Bragg mirrors serve as valuable test structures for evaluating the epitaxial uniformity of crystal growth systems. Careful characterization of half-wave space single quantum wells provides a method for determining their complex refractive indices using reflectance spectroscopy. Comparison of cross-sectional microphotoluminescence to surface-normal photoluminescence, combined with these characterization techniques, allows studies of spontaneous emission in microcavities and elucidates the difficulties with using surface-normal photoluminescence to determine the alloy composition of the mirror layers. The application of these characterization methods to visible- wavelength AlGaAs mirrors, 485-720 nm, enables the development of these mirrors for uses such as optically tailored substrates and visible surface-emitter or detector arrays.