Optical Pumping

Optical pumping uses light to affect the internal degrees of freedom of a sample of atoms in a vapor. These internal degrees of freedom are angular momentum states of the atomic ground state, which are populated when light is absorbed and emitted. This experiment reveals many phenomena of quantum mechanics including angular momentum selection rules, the density matrix, and resonance. Optical pumping is important to a wide variety of applications from the laser, to precise measurements of atomic hyperfine level splittings and atomic clocks, sensitive measurements of weak magnetic fields, and recently to enhance NMR and MRI. This experiment provides an array of measurement opportunities including measurement of optical depth, atomic electron polarization and relaxation rates, radio frequency electron paramagnetic resonance (EPR), fine structure splittings, nuclear moments, the isotopic composition of rubidium, and the investigation of resonance line shapes and their relation to exponential decay. A solid state laser diode is used in the experiment. A similar laser is used for the Doppler Free Spectroscopy experiment. The laser is described in a separate Chapter.