A demonstration apparatus for optical pumping of rubidium

Optical pumping refers to the use of light in order to elevate ("pump") the spin (intrinsic angular momentum) of an atom or molecule. This process is of interest from a pedagogical and experimental perspective because it encapsulates fundamental properties of atomic physics and quantum mechanics. Funded in part by the Office of Undergraduate Research at the University of Utah, an apparatus has been constructed for the optical pumping of rubidium atoms by resonance with a semiconductor laser. Intended specially for demonstration use in the classroom, the device is noteworthy for its compact dimensions, portability, simplicity of operation, and substantial economy relative to commercially marketed apparatus. The present work treats the theory of optical pumping, construction and architecture of the apparatus, and interpretation of selected optical-pumping phenomena demonstrated by the device.