Optical microcavity arrangements and approaches facilitate a variety of applications. According to an example embodiment of the present invention, an optical microcavity arrangement includes a microcrystal structure having a plurality of optical cavities therein to facilitate the control of light. Emitters such as colloidal quantum dots are optically coupled to the optical cavities by attaching or otherwise arranging a material, which includes the emitters, to the optical microcavity arrangement. In many applications, the emitters couple photons of a wavelength in a range of wavelengths selectively passed by the optical cavities, and are amenable to operation at relatively high temperatures (e.g., at about room temperature or higher), which is useful for a variety of applications.